Difference between revisions of "826"

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[[File:826 photo.jpg|thumb|Model 826 board]]
 
[[File:826 photo.jpg|thumb|Model 826 board]]
  
−
Sensoray's [http://www.sensoray.com/products/826.htm model 826] is a versatile analog and digital I/O system on a PCI Express board. It has 48 digital I/Os with edge detection, sixteen 16-bit analog inputs, eight 16-bit analog outputs, six 32-bit counter channels, a watchdog timer with fail-safe controller, and a flexible signal router. The board's high performance, compact size, and abundant resources make it ideally suited for a wide range of measurement and control applications.
+
This is the top-level wiki page for Sensoray's [http://www.sensoray.com/products/826.htm model 826], a versatile analog and digital I/O system on a PCI Express board. The board has 48 digital I/Os with edge detection, sixteen 16-bit analog inputs, eight 16-bit analog outputs, six 32-bit counter channels with quadrature clock decoders, three-stage watchdog timer with fail-safe controller, and a flexible signal router.
  
−
==Counters==
+
;Related pages
 +
Each board subsystem has a dedicated wiki page:
 +
* [[826 ADC|ADC]] - analog input system
 +
* [[826 DAC|DACs]] - analog output system
 +
* [[826 DIOs|DIOs]] - general-purpose digital I/Os
 +
* [[826 counters|Counters]] - counter/timers, including appnotes for interfacing incremental encoders
 +
* [[826 watchdog|Watchdog]] - watchdog timer and fail-safe controller
  
−
===Snapshot counts upon match===
+
;Please note:
 +
* Code and circuit examples are intended to function as described, but this is not guaranteed. If you discover an error, please [http://www.sensoray.com/support/message.htm?s=Web%20feedback inform the webmaster].
 +
* In code examples, error checking has been simplified or omitted for clarity. It is recommended to always perform error checking in your production software.
 +
* C language examples depend on header file <code>826api.h</code>, which should be included at the top of your source code like this:
 +
#include "826api.h"
  
−
When a snapshot is caused by counts equal to a compare register, the snapshot counts will always be equal to the compare register value.
+
==Timestamp generator==
  
−
===How to use interrupts===
+
The timestamp generator is a free-running 32-bit counter that serves as a time reference. The counter increments once per microsecond and overflows (to zero, without notification) every 2<sup>32</sup> &micro;s (approximately 71.6 minutes). It is a binary counter and consequently does not keep track of the date or time-of-day. At any moment, the current count may be sampled; such a sample is called a ''timestamp''.
  
−
:''I want to use interrupts to perform actions after a time delay. I see that counters have an "Interrupt System (IRQ)" signal but have no idea how to access it.''
+
A timestamp is automatically appended to every counter snapshot and to every ADC sample so that application programs can know (to within 1 &micro;s) when each sample was acquired. Also, application programs can read the timestamp generator at any time to get a timestamp.
  
−
Every hardware IRQ is associated with a blocking API function. In the case of counter IRQs the function is <code>S826_CounterSnapshotRead()</code>. A counter IRQ is automatically generated when a counter snapshot is captured. The API has been designed to handle interrupts for you so that you need not be concerned with the complexities of interrupt handlers -- simply call the API function and IRQs will automatically be generated and handled.
+
===Usage===
  
−
A simple way to implement a delayed interrupt is to configure the counter to count down, preload the counter with the desired time delay, and have it capture a snapshot (and thus generate an IRQ) when it reaches zero counts. To wait for the interrupt, call <code>S826_CounterSnapshotRead()</code> with a non-zero <code>tmax</code> value (maximum wait time, which must be longer than the delay time). The function will return upon interrupt and you can then perform the desired actions. For example:
+
Timestamps are particularly useful for precisely measuring the elapsed time between hardware events. Calculation of elapsed time is easy (a single subtraction) as long as the time interval doesn't exceed 71.6 minutes. It can be used in a variety of ways, including [[826 counters#Measuring speed|measuring speed]] and [[826 counters#Serial data capture|capturing serial data]].
  
−
#include "826api.h"
+
If desired, an application program can directly read the current time as shown below:
−
+
−
// Wait 0.5 seconds while other threads are allowed to run ------------------
+
−
+
−
// Configure the delay timer:
+
−
S826_CounterModeWrite(0, 0, 0x01400020);      // Configure counter0: 1 MHz down counter, auto preload @startup.
+
−
S826_CounterPreloadWrite(0, 0, 0, 500000);    // Delay time in microseconds (0.5 seconds).
+
−
S826_CounterSnapshotConfigWrite(0, 0,        // Configure snapshots:
+
−
    S826_SSRMASK_ZERO                        //  capture snapshot when counts==0
+
−
    | (S826_SSRMASK_ZERO << 16),              //  disable subsequent snapshots when counts==0
+
−
    S826_BITSET);                            //  don't alter any other snapshot enables
+
−
+
−
// Now do the delay:
+
−
S826_CounterStateWrite(0, 0, 1);              // Start the delay timer running.
+
−
S826_CounterSnapshotRead(0, 0,                // Block while waiting for timer:
+
−
    NULL, NULL, NULL,                          //  ignore snapshot counts, timestamp and reason
+
−
    S826_WAIT_INFINITE);                      //  disable function timeout
+
−
+
−
printf("Delay time has elapsed!");            // TODO: INSERT YOUR DESIRED ACTIONS HERE
+
  
−
Note that your program cannot do anything else while it waits for <code>S826_CounterSnapshotRead()</code> to return. To get around this you can call the function in a separate thread so that while the thread is waiting for the interrupt, other threads can do productive work.
+
// Read the timestamp generator's current count.  
 +
uint CurrentTimestamp(uint board)
 +
{
 +
  uint t;
 +
  S826_TimestampRead(board, &t);
 +
  return t;
 +
}
  
−
===Periodic timer===
+
The following example shows a simple application of direct timestamp reads:
  
−
:''How can I use a counter to call a function periodically?''
+
// Example: Use board0 to measure system Sleep() time.
 +
uint t1, t0 = CurrentTimestamp(0);  // Get start time.
 +
Sleep(25);                          // Sleep approximately 25 ms.
 +
t1 = CurrentTimestamp(0);            // Get end time.
 +
printf("Slept %d &micro;s", t1 - t0);      // Display actual sleep time.
  
−
Configure the counter so that it repeatedly counts down to zero and then preloads. The preload value determines the time period. A snapshot is captured every time zero counts is reached, which causes <code>S826_CounterSnapshotRead()</code> to return, whereupon you can call your periodic function.
+
==Board ID==
  
−
#include "826api.h"
+
The "BOARD NUM" switches (at top edge of board near mounting bracket) assign the board ID used by software. The ID is binary coded on the four switches and can be programmed to any value from 0 (default) to 15. A board's ID determines the corresponding ''bit'' that will be set to '1' in the value returned by <code>S826_SystemOpen</code>. If you have a single 826 board, the return value will be <code>(2^ID)</code>. If you have multiple boards, the return value is the sum of <code>(2^ID)</code> for each board. You can enter the return value [http://www.sensoray.com/support/826_boardID.htm here] to quickly determine its meaning.
−
+
−
// Call PeriodicFunction() 10 times per second
+
−
+
−
S826_CounterModeWrite(0, 0, 0x01C02020);      // Counter0: 1 MHz down counter; preload @startup and counts==0.
+
−
S826_CounterPreloadWrite(0, 0, 0, 100000);    // Period in microseconds (0.1 seconds).
+
−
S826_CounterSnapshotConfigWrite(0, 0,        // Configure snapshots:
+
−
    S826_SSRMASK_ZERO,                        //  capture snapshot when counts==0
+
−
    S826_BITWRITE);                          //  disable all other snapshot triggers
+
−
S826_CounterStateWrite(0, 0, 1);              // Start the periodic timer running.
+
−
+
−
while (1) {                                  // Repeat forever:
+
−
  S826_CounterSnapshotRead(0, 0,              //   Block while waiting for elapsed period:
+
−
      NULL, NULL, NULL,                      //   ignore snapshot values
+
−
      S826_WAIT_INFINITE);                    //   disable function timeout
+
−
  PeriodicFunction();                        //  Execute the periodic function.
+
−
}
+
  
−
===Programming incremental encoders===
+
;Examples
 +
* You have one board with ID set to 0, so the value returned by <code>S826_SystemOpen</code> will be <code>(2^0) = 1</code>.
 +
* You have two boards with IDs set to 1 and 4, so the value returned by <code>S826_SystemOpen</code> will be <code>(2^1)+(2^4) = 2+16 = 18</code>.
  
−
====Basic operation====
+
This code snippet will tell you the meaning of the value returned by <code>S826_SystemOpen</code>:
  
−
:''Which functions should I use for incremental encoders?''
+
int id, flags = S826_SystemOpen();
 +
if (flags < 0)
 +
  printf("S826_SystemOpen returned error code %d", flags);
 +
else if (flags == 0)
 +
  printf("No boards were detected");
 +
else {
 +
  printf("Boards were detected with these IDs:");
 +
  for (id = 0; id < 16; id++) {
 +
    if (flags & (1 << id))
 +
      printf(" %d", id);
 +
  }
 +
}
  
−
The flexible counter architecture allows for many options, but basic operation works as follows:
+
==Hardware version==
  
−
First configure and enable the counter channel:
+
===Reading the PWB revision===
  
−
  #include "826api.h"
+
The circuit board revision (PWB rev) is visible on the solder-side of the 826 board (opposite the mounting bracket, on the bottom corner). <code>S826_VersionRead</code> returns the PWB rev as a numeric value with decimal range [0:31], which corresponds to a text string in the standard ASME version letter sequence. The following code shows how to convert this 32-bit value to the alphabetic revision code seen on the board:
 +
 
 +
// Read and display version info from board 0
 +
 +
// Extract major_version, minor_version and build_number from a 32-bit version number:
 +
  #define VER_FIELDS(N) ((N) >> 24) & 0xFF, ((N) >> 16) & 0xFF, (N) & 0xFFFF
 +
 +
const char *revchar[] = {  // ASME revision sequence
 +
  "A",  "B",  "C",  "D",  "E",  "F",  "G",  "H",
 +
  "J",  "K",  "L",  "M",  "N",  "P",  "R",  "T",
 +
  "U",  "V",  "W",  "Y",  "AA", "AB", "AC", "AD",
 +
  "AE", "AF", "AG", "AH", "AJ", "AK", "AL", "AM"
 +
};
 
   
 
   
−
  S826_CounterModeWrite(0, 0, 0x00000070);  // Configure counter 0 as incremental encoder interface.
+
  uint api, drv, bd, fpga;
−
  S826_CounterStateWrite(0, 0, 1);         // Start tracking encoder counts.
+
int errcode = S826_VersionRead(0, &api, &drv, &bd, &fpga);  // Read version info.
 +
  if (errcode == S826_ERR_OK) {                              // If no errors then display info:
 +
  printf("API version    = %d.%d.%d\n", VER_FIELDS(api));  //  API major.minor.build
 +
  printf("Driver version = %d.%d.%d\n", VER_FIELDS(drv));   //   DRVR major.minor.build
 +
  printf("FPGA version  = %d.%d.%d\n", VER_FIELDS(fpga));  //  FPGA major.minor.build
 +
  printf("PWB revision  = Rev %s\n",  revchar[bd & 31]);  //  PWB rev as seen on circuit board
 +
}
 +
else
 +
  printf(" S826_VersionRead returned error code %d", errcode);
  
−
To read the instantaneous encoder counts without invoking a snapshot:
+
===Rev C changes===
  
−
uint counts;
+
Sensoray has developed Revision C of the 826 circuit board. This change was necessary due to the impending EOL (end-of-life) of a critical component. Specifically, the critical component (PCI Express interface chip) and FPGA were removed and replaced by a new FPGA, which absorbed the functions of the two removed components.
−
S826_CounterRead(0, 0, &counts);          // Read current encoder counts.
+
−
printf("Encoder counts = %d\n", counts);  // Display encoder counts.
+
  
−
In some cases, when reading the instantaneous counts you may need to know when the counts were sampled. For example, two ordered pairs of (counts, time) are needed for speed measurement (dc/dt). You could rely on the determinism of your software and operating system to sample the counts at precise times, but there's an easier and much more accurate way: trigger a snapshot (via software command) and then read the counts and exact sample time (accurate to within one microsecond):
+
<u>'''Applications and developers are not affected by this change'''</u>
  
−
uint counts;      // encoder counts when the snapshot was captured
+
The Rev C board is fully compatible with Rev B boards and applications:
−
uint timestamp;  // time the snapshot was captured
+
* Mechanical attributes are unchanged, including board dimensions and placements of connectors, switches, indicator LEDs, and hold-down bracket.
−
+
* Connector pinouts, electrical and timing specifications are unchanged.
−
S826_CounterSnapshot(0, 0);              // Trigger snapshot on counter 0.
+
* Rev C is 100% software compatible with Rev B on all software layers: application, API and driver (including user-developed drivers and APIs for RTOS, etc.).
−
S826_CounterSnapshotRead(0, 0,           // Read the snapshot:
+
−
    &counts, &timestamp, NULL,            //  receive the snapshot info here
+
−
    0);                                  //  no need to wait for snapshot; it's already been captured
+
−
printf("Counts = %d at time = %d\n", counts, timestamp);
+
  
−
The encoder counts can be changed to an arbitrary value at any time. This is typically done when the encoder is at a known reference position (e.g., at startup or whenever mechanical registration is required), but not at other times as it would disrupt position tracking. To change the counts, write the new counts value to the Preload0 register and then call <code>S826_CounterPreload()</code> to force a preload:
+
Rev B and Rev C boards can be used interchangeably in new and existing applications. From an application's perspective, the only detectable differences between Rev B and Rev C boards are the version numbers returned by the API function S826_VersionRead():
 +
* S826_VersionRead() will report the PWB version as Rev B or Rev C as appropriate for the board's hardware version.
 +
* S826_VersionRead() will report FPGA version 0.0.70 or higher for Rev C boards, or version 0.0.69 or lower for Rev B boards.
  
−
S826_CounterPreloadWrite(0, 0, 0, 12345); // Write desired counts value (12345) to Preload0 register.
+
==Connector pinouts==
−
S826_CounterPreload(0, 0, 0, 0);          // Jam Preload0 value into counter.
+
  
−
====Using interrupts====
+
The following drawings show the pinouts of the board's header connectors as viewed from the top (component) side of the circuit board:
  
−
This code snippet employs hardware interrupts to block the calling thread until the encoder counts equals a particular value. Other threads are allowed to run while the calling thread waits for the counter to reach the target value. A snapshot is captured when the target count is reached. The snapshot generates an interrupt request, which in turn causes <code>S826_CounterSnapshotRead()</code> to return. The example ignores the snapshot counts (which will always equal the target value), the timestamp, and the reason code (which will always indicate a Match0 event).
+
<gallery heights=350px widths=180px perrow=3>
 +
File:826 pinout J1.gif
 +
File:826 pinout J2.gif
 +
File:826 pinout J3.gif
 +
File:826 pinout J4.gif
 +
File:826 pinout J5.gif
 +
File:826 pinout P2.gif
 +
</gallery>
  
−
S826_CounterCompareWrite(0, 0, 0,        // Set Compare0 register to target value:
+
==Software==
−
    5000);                                //  5000 counts (for this example)
+
−
S826_CounterSnapshotConfigWrite(0, 0,    // Enable snapshots:
+
−
    S826_SSRMASK_MATCH0,                  //  when counts==Compare0
+
−
    S826_BITWRITE);                      //  disable all other snapshot triggers
+
−
S826_CounterSnapshotRead(0, 0,            // Wait for counter to reach target counts:
+
−
    NULL, NULL, NULL,                    //  ignore snapshot counts, timestamp and reason
+
−
    S826_WAIT_INFINITE);                  //  disable function timeout
+
−
printf("Counter reached target counts");
+
  
−
In some cases you may want to wait for more than one counter event at the same time. This example shows how to wait for the encoder counts to reach an upper or lower limit (whichever occurs first). Furthermore, it will only wait for a limited amount of time. To set this up, the count limits are programmed into Compare registers and then snapshots are enabled for matches to both Compare registers. To set a limit on how long to wait, a time limit value is specified by <code>tmax</code> when calling <code>S826_CounterSnapshotRead</code>. Since a snapshot can be caused by different events, we must know what triggered a snapshot in order to decide how to handle it; this is indicated by the snapshot's reason flags.
+
===C examples===
  
−
uint counts;      // encoder counts when the snapshot was captured
+
A variety of [http://www.sensoray.com/downloads/s826_example.c C programming examples] have been collected together in a common source file to illustrate how to program resources on the 826.
−
uint timestamp;  // time the snapshot was captured
+
−
uint reason;      // event(s) that caused the snapshot
+
−
uint errcode;    // API error code
+
−
+
−
S826_CounterCompareWrite(0, 0, 0, 3000);  // Set Compare0 register to low limit (3000 counts)
+
−
S826_CounterCompareWrite(0, 0, 1, 4000);  // Set Compare1 register to high limit (4000 counts)
+
−
S826_CounterSnapshotConfigWrite(0, 0,    // Enable snapshots:
+
−
    S826_SSRMASK_MATCH0                  //  when counts==low limit
+
−
    | S826_SSRMASK_MATCH1,                //  or when counts==high limit
+
−
    S826_BITWRITE);                      //  disable all other snapshot triggers
+
−
errcode = S826_CounterSnapshotRead(0, 0,  // Wait for a snapshot:
+
−
    &counts, &timestamp, &reason,        //  receive the snapshot info here
+
−
    10000000);                            //  timeout if wait exceeds 10 seconds (10000000 us)
+
−
+
−
switch (errcode) {                        // Decode and handle the snapshot:
+
−
  case S826_ERR_NOTREADY:
+
−
    printf("Timeout -- counter didn't hit limits within 10 seconds; current counts = %d", counts);
+
−
    break;
+
−
  case S826_ERR_OK:
+
−
    if (reason & S826_SSRMASK_MATCH0)
+
−
      printf("Counter reached upper limit at timestamp %d", timestamp);
+
−
    if (reason & S826_SSRMASK_MATCH1)
+
−
      printf("Counter reached lower limit at timestamp %d", timestamp);
+
−
}
+
  
−
====Output pulse every N encoder pulses====
+
===VB.NET demo===
  
−
:''Can the 826 generate an output pulse every N shaft encoder pulses?''
+
To help you jump-start your project, we offer the [[826 demo (VB.NET)|VB.NET demo for model 826]]. This demo program provides a pre-built Windows executable with a GUI for nearly every hardware resource on the board. All source files are provided, along with a VisualStudio project.
  
−
A short (20 ns) pulse can be generated with one counter ("counterA") and one general-purpose I/O (DIO). A longer output pulse can be generated with two counters ("counterA" and "counterB") and one DIO.
+
===Programming in C#===
  
−
First, initialize the 826:
+
Each 826 SDK includes a C# demo application. These demos show how to call API functions from C#, and can serve as a useful starting point for a custom application.
−
* Configure counterA as an incremental encoder interface.
+
−
* Configure counterA to capture snapshots upon Compare register matches.
+
−
* Configure counterA's ExtOut mode (OM=1) to output a pulse upon Compare register match.
+
−
* Case 1: Short output pulse:
+
−
** Program the signal router to output counterA's ExtOut signal on the DIO. The pulse duration will be 20 ns and consequently an external pull-up must be added to the DIO to speed up the rising edge of the output pulse (see [[826#Using external pull-up resistors|Using external pull-up resistors]] for details).
+
−
* Case 2: Output pulse with programmable duration:
+
−
** Configure counterB as a pulse generator, using counterA's ExtOut as a preload trigger. Program the preload counts to the desired pulse width.
+
−
** Program the signal router to output counterB's ExtOut signal on the DIO.
+
  
−
After initializing, program counterA's Compare register with the encoder counts that are to trigger the next output pulse, then wait for a snapshot. When the counts matches the Compare register, a snapshot will be captured and the output pulse will automatically be generated. Upon receiving the snapshot, the application must write into the Compare register the counts corresponding to the next output pulse, before the counter reaches that value.
+
====Linux demo====
  
−
===Unexpected snapshots===
+
In the Linux SDK, a C# GUI demo is available which uses Linux mono. To get the required libraries on Ubuntu, type:
 +
"sudo apt-get install mono-complete"
 +
For a C# development environment, type:
 +
"sudo apt-get install monodevelop"
  
−
:''Why do I occasionally get two snapshots (upon counts match) from my incremental encoder when only one is expected?''
+
====Pointer arguments====
  
−
Assuming your encoder has not changed direction, the unexpected snapshots are probably being triggered by noise or slow edges on the encoder clock signals. This is possible even when the snapshot timestamps are identical, because encoder clocks are sampled every 20 nanoseconds whereas timestamp counts are incremented only once per microsecond.
+
Many of the API functions have pointer arguments. This is no problem for C#, which allows you to pass function arguments by reference. To see how this is done, consider the <code>S826_AdcEnableRead</code> function:
  
−
If this is what is happening, unexpected snapshots can be prevented by calling <code>S826_CounterFilterWrite()</code> to establish a clock filter. A small filter value is usually sufficient -- just enough to clean up clock edges, but not so long that valid encoder counts will be missed. For example, this will set the clock filter to 100 ns (index input will not be filtered):
+
The C prototype is:
  
−
  #define FILT_NS    100                // Filter time in ns -- change as desired to multiple of 20.
+
  int S826_AdcEnableRead(unsigned int board, unsigned int *enable);
−
#define FILT_RES  20                // Filter resolution in nanoseconds.
+
−
#define FILT_CLK  (1 << 30)          // Bit flag to enable clock filtering.
+
−
S826_CounterFilterWrite(0, 0,        // Activate clock filter on counter 0.
+
−
    FILT_CLK + FILT_NS / FILT_RES);
+
  
−
Another way to handle this is to configure the Match snapshot trigger to become automatically disabled when it fires. Note that if you use this method, you will need to re-enable the Match trigger to capture snapshots of subsequent matches.
+
So in C# you should declare the function this way:
  
−
  S826_CounterSnapshotConfigWrite(0, 5, // Configure snapshots on counter 5:
+
  [DllImport("s826.dll", CallingConvention = CallingConvention.StdCall)]
−
    S826_SSRMASK_MATCH0                //  enable snapshot upon Match0 (counts==Compare0 register)
+
static extern Int32 S826_AdcEnableRead(UInt32 board, ref UInt32 enable);  
−
    | (S826_SSRMASK_MATCH0 << 16),     //  disable subsequent Match0 snapshots upon Match0
+
Now you can call the function this way:
−
    S826_BITWRITE);                   //  disable all other snapshot triggers
+
  
−
===ExtOut timing===
+
Uint32 isEnabled;
 +
Int32 errcode = S826_AdcEnableRead(0, ref isEnabled);
  
−
:''What is the delay from input clock to ExtOut?''
+
===Labview===
  
−
The input clock is sampled every 20 ns, so a clock edge is recognized 0 to 20 ns after the edge. The counts change 20 ns after the edge is recognized. ExtOut changes 20 ns after the counter transitions to zero (or match value). So, the delay from input clock edge to ExtOut edge is 40 to 60 ns.
+
Before running an 826 virtual instrument (VI) under Labview, make sure you install the latest versions of the 826 DLL (s826.dll) and device driver (both are contained in the 826 SDK, which you can obtain from the ''Downloads'' tab of the [http://www.sensoray.com/products/826.htm 826 product page]).
  
−
====Using external pull-up resistors====
+
Each VI is a basically a wrapper for a DLL function and consequently the VIs are dependent on the DLL, which in turn depends on the driver. Board hardware and firmware version numbers will be automatically read from the 826 board by software when all dependencies are satisfied -- it is not necessary to manually enter any board selection information except the board number, which is specified by the board's switch settings (factory default is board number 0).
  
−
* ''My PWM stops working when it outputs high frequencies. Why does this happen and how can I prevent it?''
+
The VIs are not independently documented, but since each VI wraps a DLL function, the DLL documentation effectively explains the function of each associated VI. The DLL documentation can be found in the 826 product manual (download from the [http://www.sensoray.com/products/826.htm 826 product page] ''Documentation'' tab).
  
−
The PWM signal (from the counter's ExtOut) is output by a DIO channel, which drives the signal to 0 V in the ''on'' state and is high-impedance in the ''off'' state. In the ''off'' state, the channel's internal 10K ohm resistor pulls up the signal to +5 V. This resistance (combined with circuit capacitance) slows down the signal's rise time, which delays its transition to logic '1'. As the ''off'' time decreases, the delay time (which is constant) becomes a higher percentage of the ''off'' time. When the ''off'' time becomes too short (i.e., when delay equals or exceeds ''off'' time), the PWM output will seem to "stop" because there is not enough time for the signal to reach logic '1'. This situation can arise when the PWM is operating at high frequencies or generating short positive pulses.
+
The VIs may be installed under Labview's instrument library (e.g., "instr.lib\Sensoray 826") or elsewhere if desired. Refer to Labview documentation for information about paths and other relevant topics.
  
−
This phenomenon can be prevented by speeding up the signal rise time. This is done by adding an external pull-up resistor (and minimizing external capacitance) on the signal net. The following table shows nominal rise times for unloaded DIO pins. Lower resistance values may be needed to compensate external circuit capacitance, but do not use an external pull-up resistor having less than 220 ohms (to prevent excessive DIO output current).
+
===Matlab===
  
−
{| class="wikitable"
+
To use an 826 with Matlab you must first install the latest 64-bit versions of the 826 API (s826.dll) and device driver; these are both part of the 826 SDK, which you can obtain from the ''Downloads'' tab of the [http://www.sensoray.com/products/826.htm 826 product page]. You may then use Matlab's <code>loadlibrary()</code> function to enable access to the API, and <code>calllib()</code> to call API functions. The API functions are described in the 826 product manual, which can be found on the [http://www.sensoray.com/products/826.htm 826 product page] ''Documentation'' tab. The following example illustrates how this works.
−
! style="text-align:left;"| External pull-up
+
−
! style="text-align:left;"| DIO rise time
+
−
|-
+
−
|None
+
−
|200 ns
+
−
|-
+
−
|1.2K ohm
+
−
|20 ns
+
−
|-
+
−
|680 ohm
+
−
|10 ns
+
−
|}
+
  
−
===How to configure a counter for PWM operation===
+
Note: Matlab cannot execute <code>loadlibrary()</code> unless a compatible C compiler is installed on your computer. If Matlab complains about an "Error using loadlibrary" because "No supported compiler was found" then you must download and install one of the Matlab-compatible compilers (e.g., MinGW-w64) to resolve this issue. Please consult Mathworks for a list of compatible compilers.
  
−
This example shows how to configure counter channel 0 to operate as a PWM generator with the output appearing on DIO channel 0. Note that you ''must'' call <code>S826_SafeWrenWrite()</code> before calling <code>S826_DioOutputSourceWrite()</code>; if you neglect to do this then the PWM signal will not appear on DIO 0.
+
% Simple Matlab example: turn on general-purpose digital I/O 2 ***************************
−
 
+
−
  #include "826api.h"
+
% Change these values as required:
 +
hdrPath = 'C:\Sensoray\826api.h';          % Path to API header
 +
dllPath = 'C:\Windows\System32\s826.dll';   % Path to API executable
 +
  board = 0;                                  % Use 826 board #0 (i.e., board w/ID switches set to 0)
 
   
 
   
−
  uint data[2]= {1, 0}; // DIO 0
+
  loadlibrary(dllPath, hdrPath, 'alias', 's826');     % Load the API.
−
  S826_SafeWrenWrite(0, 2);                   // Enable writes to DIO signal router.
+
  boardflags = calllib('s826', 'S826_SystemOpen');   % Open API and detect all boards.
−
  S826_DioOutputSourceWrite(0, data);         // Route counter0 output to DIO 0.
+
  if (boardflags < 0)                                % If API failed to open
−
  S826_CounterModeWrite(0, 0, 0x01682020);   // Configure counter0 for PWM, with auto-preload when starting.
+
    disp("S826_SystemOpen error");                 %  Report error.
−
S826_CounterPreloadWrite(0, 0, 0, 900);    // On time in us (0.9 ms).
+
  else                                                % Else
−
S826_CounterPreloadWrite(0, 0, 1, 500);    // Off time in us (0.5 ms).
+
    if (boardflags ~= bitshift(1, board))          %  If board #0 was not detected
−
S826_CounterStateWrite(0, 0, 1);           // Start the PWM generator.
+
        disp("Failed to detect 826 board");         %    Report error (check board's switch settings).
 +
    else                                            %  Else ...
 +
        buf = libpointer('uint32Ptr', [6 0]);       %     Allocate buffer for DIO state data.
 +
        errcode = calllib('s826', ...              %    Turn on DIO1 and DIO2.
 +
            'S826_DioOutputWrite', board, buf, 0);
 +
        clear buf;                                  %     Free buffer.
 +
        if (errcode ~= S826_ERR_OK)
 +
            disp('DIO write problem')              %    Report error if DIO write failed.
 +
        end
 +
    end
 +
    errcode = calllib('s826', 'S826_SystemClose'); %  Close API.
 +
end
 +
unloadlibrary s826;                                % Unload the API.
  
−
===Fail-safe PWM generator===
+
====Matlab SDK====
  
−
''I'm using a PWM output to control a motor. Is there a way to automatically shut off the motor if my program crashes?''
+
Sensoray offers an open-source software development kit for Matlab programmers, which you can obtain from the ''Downloads'' tab of the [http://www.sensoray.com/products/826.htm 826 product page]. The Matlab SDK includes two files:
 +
* <code>s826.m</code> is a class that defines useful constants and provides wrappers for all 826 API functions. Include this file in any project that interacts with model 826 boards.
 +
* <code>s826_demo.m</code> is a short program that demonstrates how to use the s826 class.
  
−
Yes, you can use the watchdog timer and fail-safe controller to force the PWM output to a constant state. To do this, configure the watchdog to activate safemode when it times out, as shown in this simplified block diagram:
+
===ROS (Robot Operating System)===
  
−
[[File:826PwmWatchdog.gif|550px|center|alt=Fail-safe PWM generator]]
+
Sensoray SDKs do not include a ROS package, but the Linux SDK has everything needed to create one. The simplest way to use ROS with model 826 is to install the Linux 826 device driver and API (shared library), and then call the API functions as shown in the following example. Note that this example is coded in C++, but you can easily call the API functions from Python or any other language.
  
−
Before enabling the PWM generator or watchdog, program the desired PWM failsafe level into the DIO channel's <code>SafeData</code> register; this specifies the signal that will be sent to your motor controller when your program crashes (which will shut off the motor). Note that the DIO output is active-low. The <code>SafeEnable</code> register is set to '1' by default, thus enabling fail-safe operation on the DIO channel. Next, program the watchdog interval and start the watchdog running. Finally, start the PWM running.
+
///////////////////////////////////////////////////////////////////////////////////////////////////////////
−
 
+
// Simple ROS (Robot Operating System) example for Sensoray 826 PCI Express analog/digital IO board.
−
After enabling the watchdog, your program must periodically kick it to prevent it from timing out, by calling <code>S826_WatchdogKick()</code>. When your program is running normally, the PWM signal will appear on the DIO pin. If your program crashes (or fails to kick the watchdog in a timely manner), the watchdog will time-out and activate the fail-safe controller. This will switch the DIO pin to the level specified by the <code>SafeData</code> register, which in turn will halt the motor.
+
// Function: Publishes 16 analog inputs 10 times per second
−
 
+
  ///////////////////////////////////////////////////////////////////////////////////////////////////////////
−
  #include "826api.h"
+
 
   
 
   
−
  #define CRASH_DET_SECONDS 0.5  // Halt motor if program fails to kick watchdog within this time.
+
  #define X826(func)   if ((errcode = (func)) != S826_ERR_OK) { printf("\nERROR: %d\n", errcode); return; }    // Call function and process error
−
#define MOTOR_HALT_LEVEL  0   // DIO pin level ('0'=5V, '1'=0V) that will halt motor.
+
 
   
 
   
−
  uint wdtime[5] = {(uint)(50000000 * (CRASH_DET_SECONDS)), 1, 1, 0, 0}; // watchdog interval
+
  int PublishAINChannels()
−
uint dio_routing[2]= {1, 0};                                           // map counter0 to DIO 0
+
{
−
uint safe_data[2]= {MOTOR_HALT_LEVEL, 0};                             // fail-safe level
+
    int adcbuf[16];    // adc data buffer
 +
    uint slotlist;     // timeslot flags
 +
    uint slot;         // timeslot index (and ain channel number)
 +
    uint board = 0;     // board ID
 +
    int errcode;
 
   
 
   
−
// Create a fail-safe PWM generator using counter0 and DIO 0.
+
    // Initialize data array for publisher
−
S826_SafeWrenWrite(0, 2);                   // Enable writes to watchdog, router and SafeData.
+
    std_msgs::Int16MultiArray data_array;
−
S826_DioSafeWrite(0, safe_data, 2);        // Specify DIO state to use when program crashes.
+
    data_array.layout.dim.push_back(std_msgs::MultiArrayDimension());
−
S826_DioOutputSourceWrite(0, dio_routing);  // Route counter0 output to DIO 0.
+
    data_array.layout.dim[0].label = "board-" + to_string(board) + " AIN";
−
S826_CounterModeWrite(0, 0, 0x01682020);   // Config counter0 for PWM; preload when starting.
+
    data_array.layout.dim[0].size = 16;
−
S826_CounterPreloadWrite(0, 0, 0, 900);     // PWM on time in us (0.9 ms).
+
    data_array.layout.dim[0].stride = 1;
−
S826_CounterPreloadWrite(0, 0, 1, 500);     // PWM off time in us (0.5 ms).
+
    data_array.layout.data_offset = 0;
−
S826_WatchdogConfigWrite(0, 0x10, wdtime); // Set wdog interval; trig safemode upon timeout.
+
   
 +
    // Configure adc and start it running.
 +
    for (slot = 0; slot < 16, slot++ )                         // Configure slots: chan = slot number, settle time = 20 us, range = +/-10 V
 +
        X826(S826_AdcSlotConfigWrite(board, slot, slot, 20, S826_ADC_GAIN_1));
 +
    X826(S826_AdcSlotlistWrite(board, 0xFFFF, S826_BITWRITE)); // Enable all slots.
 +
    X826(S826_AdcTrigModeWrite(board, 0));                     // Select continuous trigger mode.
 +
    X826(S826_AdcEnableWrite(board, 1));                       // Start conversions.
 
   
 
   
−
  // Start the PWM generator running.
+
    ROS_INFO("\tPublishing AIN Channels");
−
  S826_WatchdogEnableWrite(0, 1);             // Start watchdog. PROGRAM MUST KICK IT FROM NOW ON!
+
   
−
  S826_CounterStateWrite(0, 0, 1);           // Start the PWM generator.
+
    ros::Rate loop_rate(10);
 +
 +
    while (ros::ok())
 +
    {
 +
        // Wait for next publish time. This is at top of loop so first ADC burst will complete before we try to read the data.
 +
        // Otherwise we might get bogus data the first time through the loop.
 +
        loop_rate.sleep();
 +
   
 +
        // Fetch ADC data
 +
        data_array.data.clear();
 +
        slotlist = 0xFFFF; // from all 16 slots
 +
        errcode = S826_AdcRead(board, adcbuf, NULL, &slotlist, 0);
 +
 +
        // Handle errors
 +
        if ((errcode != S826_ERR_OK) && (errcode != S826_ERR_MISSEDTRIG)) {  // this app doesn't care about adc missed triggers
 +
            printf("\nERROR: %d\n", errcode);
 +
            break;
 +
        }
 +
   
 +
        // Publish ADC data
 +
        for (slot = 0; slot < 16; slot++) {
 +
            // Publishing raw data (16-bit signed int). Convert to +/-10V by multiplying by 10/32768.
 +
            // example: cout << (double)(data_array.data[i] * 10) / 32768 << endl;
 +
            data_array.data.push_back((short)(adcbuf[slot] & 0xFFFF));
 +
        }
 +
        analog_input_pub.publish(data_array);
 +
    }
 +
 +
    S826_AdcEnableWrite(board, 0);         // Halt conversions.
 +
    return errcode;
 +
}
  
−
===Phase-locked PWM outputs===
+
===Resources for custom driver development===
  
−
Some applications require multiple, phase-locked PWM outputs. Although the 826's counter channels do not directly support phase locking, it is possible to simulate phase-locked PWM outputs by using counters configured as hardware-triggered one-shots. This technique can be used in a variety of ways.
+
[[File:826 software stack.png|thumb|300px|826 software stack. The generic API is portable &mdash; to port, simply adapt the Linux driver and HAL for your OS/RTOS.]]
 +
:''I want to develop my own device driver for the 826. Does Sensoray offer any resources for custom driver development?''
  
−
====Example: quadrature generator====
+
Yes, we provide these resources free of charge:
  
−
A quadrature generator can be implemented with three counter channels and two DIOs as shown below. Except for DIO load connections, no external wiring is required (counter and DIO interconnects are established by the board's programmable signal router).
+
* '''Linux Software Development Kit (SDK)''' - Includes source code for the 826 driver, hardware abstraction layer (HAL) and API middleware, comprising a complete 826 software stack for Linux. The generic API is operating system independent and thread-safe, which makes this SDK a great starting point for porting to any operating system. The stack has been carefully designed for reliable operation in and for easy porting to real-time operating systems. The SDK can be found on the Downloads tab of the [http://www.sensoray.com/products/826.htm 826 product page].
 +
* '''Model 826 Technical Manual''' - This comprehensive manual explains the API and 826 hardware in detail (download from the Documentation tab of the [http://www.sensoray.com/products/826.htm 826 product page]).
 +
* '''Register Map''' - A map of the board's hardware registers is available [http://www.sensoray.com/downloads/man_826_register_map.pdf here]. The registers are accessed through PCI BAR 2. Registers appear in both banked and flat address spaces. The banked space is only required for rev 0 boards; you should use the flat space exclusively if you have a later rev, as this will yield superior performance.
  
−
[[File:826 quadrature gen.gif|500px|center|alt=Quadrature generator]]
+
===Software updates===
  
−
The counter channels are configured as follows:
+
1. Windows 3.3.4
 +
* C# demo application added to SDK. Error checking for invalid modes to S826_CounterModeWrite.
 +
2. Linux 3.3.5
 +
* C# GUI demo available, using Linux mono.
  
−
*CH0 - PWM with output on DIO1.
+
===Windows===
−
*CH1 - 1-shot with IndexSource=ExtOut0, preload upon Index. This delays Phase2 wrt Phase1.
+
−
*CH2 - 1-shot with IndexSource=ExtOut1, preload upon Index, output on DIO2. This generates the Phase2 output pulse.
+
  
−
====Example: 3-phase controller====
+
====Custom installation and re-distribution====
  
−
A 3-phase PWM controller (shown below) can be created by extending the above example. This is implemented with five counter channels and three DIOs (channel numbers are arbitrarily assigned). Except for DIO load connections, no external wiring is required (counter and DIO interconnects are established by the board's programmable signal router).
+
Sensoray's installer uses the Nullsoft Scriptable Install System ([https://en.wikipedia.org/wiki/Nullsoft_Scriptable_Install_System NSIS]). It is created from a .NSI script. The core API is installed as follows in NSI script code:
  
 +
Section "Core API"
 +
SectionIn RO
 +
${If} ${RunningX64}
 +
  SetOutPath "$WINDIR\system32";
 +
  !insertmacro  DisableX64FSRedirection
 +
  File "..\mid-826\code\Release64\s826.dll";
 +
  !insertmacro  EnableX64FSRedirection
 +
  SetOutPath "$WINDIR\SysWOW64";
 +
  File "..\mid-826\code\Release\s826.dll";
 +
${Else}
 +
  SetOutPath "$WINDIR\system32";
 +
  File "..\mid-826\code\Release\s826.dll";
 +
${EndIf}
 +
SectionEnd
  
−
[[File:826 3Phase pwm.png|500px|center|alt=3-phase PWM generator]]
+
The drivers are installed via dpinst.exe in the NSI script as follows:
  
 +
Section "Drivers"
 +
SectionIn RO
 +
CreateDirectory "$INSTDIR\driver\x64";
 +
SetOutPath "$INSTDIR\driver\x64";
 +
File "..\cd\driver\x64\dpinst.exe";
 +
File "..\cd\driver\x64\s826.cat";
 +
File "..\cd\driver\x64\s826.inf";
 +
File "..\cd\driver\x64\s826.sys";
 +
File "..\cd\driver\x64\s826filter.cat";
 +
File "..\cd\driver\x64\s826filter.inf";
 +
File "..\cd\driver\x64\s826filter.sys";
 +
File "..\cd\driver\x64\WdfCoInstaller01009.dll";
 +
CreateDirectory "$INSTDIR\driver\x32";
 +
SetOutPath "$INSTDIR\driver\x32";
 +
File "..\cd\driver\x32\dpinst.exe";
 +
File "..\cd\driver\x32\s826.cat";
 +
File "..\cd\driver\x32\s826.inf";
 +
File "..\cd\driver\x32\s826.sys";
 +
File "..\cd\driver\x32\s826filter.cat";
 +
File "..\cd\driver\x32\s826filter.inf";
 +
File "..\cd\driver\x32\s826filter.sys";
 +
File "..\cd\driver\x32\WdfCoInstaller01009.dll";
 +
MessageBox MB_OK "Driver installation dialog will pop-up. Follow the prompts and click Finish when done"
 +
${If} ${RunningX64}
 +
  ExecWait '"$INSTDIR\driver\x64\dpinst.exe" /f'
 +
${Else}
 +
  ExecWait '"$INSTDIR\driver\x32\dpinst.exe" /f'
 +
${EndIf}
 +
NoInstallDriver:
 +
SectionEnd
  
−
In the above example, counter channels are configured as follows:
+
:''What other libraries does the installer install as part of the Core API?''
  
−
*CH0 - PWM with output on DIO1.
+
The 826 is compiled with Microsoft Visual Studio C++ 2008. The re-distributables for C++ must be installed. The installer installs this library silently running the command:
−
*CH1 - 1-shot with IndexSource=ExtOut0, preload upon Index. This delays Phase2 wrt Phase1.
+
"vcredist_x86.exe /q"
−
*CH3 - 1-shot with IndexSource=ExtOut1, preload upon Index. This delays Phase3 wrt Phase2.
+
−
*CH2 - 1-shot with IndexSource=ExtOut1, preload upon Index, output on DIO2. This generates the Phase2 output pulse.
+
−
*CH4 - 1-shot with IndexSource=ExtOut3, preload upon Index, output on DIO3. This generates the Phase3 output pulse.
+
  
−
===Serial data capture===
+
and the following additional command on 64-bit systems:
 +
"vcredist_x64.exe /q"
  
−
A counter channel can be used to capture serial data and timing information by leveraging its snapshot FIFO. This is especially useful for capturing data from irregularly-timed sources such as bar code wands. The basic idea is to apply the serial data signal to the counter's IX input and configure the counter to capture snapshots on IX signal edges. The computer can then simply allow the channel to acquire snapshots while it asynchronously reads and processes snapshots from the FIFO.
+
These re-distributables are available from Microsoft for [https://www.microsoft.com/en-us/download/details.aspx?id=2092 x64] and [https://www.microsoft.com/en-us/download/details.aspx?id=5582 x86].
  
−
In each snapshot, only the timestamp and reason flags are of interest (counts are ignored). The reason flag indicates whether a snapshot was triggered by rising or falling edge, and the timestamp indicates the time when the edge occurred. For example, in the serial data waveform shown below, the first rising edge (A) caused a snapshot to be captured when the timestamp generator value was 100, and the reason code indicates the snapshot was triggered by a rising edge.
+
:''Are any other libraries required?  I installed the libraries above, but the demo doesn't work with my custom installer?''
  
−
[[File:826 serial data capture.png|500px|center|alt=Serial data capture]]
+
The demo is written using .NET libraries (version 3.5). These are also available from Microsoft [https://www.microsoft.com/en-us/download/details.aspx?id=25150 here]. The executable can be silently installed using this command:
 +
"dotnetfx35setup.exe /qb"
  
−
Any two consecutive snapshots represent a matched pair of rising/falling or falling/rising edges, corresponding to an interval during which the serial data value was '1' or '0', respectively. For example, in the waveform shown above, snapshots A and B bracket a '1' interval. It is possible to determine the binary value of the serial data from the first reason code, and the duration of the data value from the difference between the timestamps.
+
:''Could I obtain the full 826 NSI script as a template for creating my own installer?''
  
−
To see how this works, consider the above serial data waveform. The counter automatically captures a snapshot for each of the edge events A, B, C and D. When the computer considers snapshots A and B, it determines that the serial data was '1' during interval A-B because A was triggered by a serial data rising edge. Furthermore, it knows that the serial data held at '1' for 300 microseconds (the difference between the A and B timestamps). Similary, it can determine that interval B-C was a logic '0' lasting 200 microseconds, and C-D was a 400 microsecond logic '1'.
+
Yes, the full script is available [http://www.sensoray.com/wiki/index.php?title=826_NSIS_Install_Script here].
  
−
For maximum efficiency, consider using a dedicated thread to read the FIFO. This tends to make the application event-driven and eliminates polling, because the thread can wait in <code>S826_CounterSnapshotRead()</code> for the next snapshot without wasting CPU time. Also, this decouples the timing of serial data acquisition from other tasks, thereby greatly simplifying overall software development and maintenance. If fast processing of the serial data is required, raise the thread priority to an appropriately high level.
+
====Silent install====
  
−
===Mode register decoder utility===
+
:''I want to run the installer silently. Do you have any way to do this?''
  
−
:''Is there an easy way to convert a mode register value to a human readable description of counter settings?''
+
There are many options.  For re-distribution, you may create your own installation package.  Also, starting with version 3.3.9, there are additional command line options to quiet the setup.exe installer from command line or batch file.  These options are described below. 
  
−
Yes: download Sensoray's [http://www.sensoray.com/downloads/util_826_DecodeCounterMode.zip counter mode decoder] utility program (Windows compatible). Run the program and enter the mode register value to see an English language description of the counter mode settings.
+
:''What are the options for silent install?''
  
−
==ADC==
+
The basic silent install is invoked by running the following command from command line or batch script:
 +
"setup.exe /S"
  
−
===Calibration errors caused by missing shunt===
+
Please note that the /S is case sensitive and must be upper case.
  
−
On 826 SDKs earlier than version 3.2.0, analog calibration values will not be applied without J6 (labeled "Calibration Enable") installed. A missing shunt is intended to protect against accidental overwriting of calibration values, but in these SDKs it also prevents the reading of those values. This is resolved in SDK version 3.2.0 and above; in these versions the shunt functions as intended and must be installed only when calibrating the board (though leaving it installed all the time is okay).
+
:''I've pre-installed the drivers and don't want to re-install them during the installation? Is there a command for that?''
 +
"setup.exe /S /no_driver=1"
  
−
If board calibration is incorrect, make sure J6 is installed or upgrade to SDK version 3.2.0 or higher. The 826 SDK can be downloaded from the [http://www.sensoray.com/products/826.htm 826 product page].
+
:''Is there an additional command to not install the demo programs?''
 +
Yes, in version 3.3.9, the following command will install the required DLLs and system libraries, but no drivers or demo programs.
 +
"setup.exe /S /no_driver=1 /no_demos=1"
  
−
===Apparent nonlinearity===
+
:''I want to install the drivers silently, but there is always a pop-up to verify.''
  
−
[[File:AdgGroundReference.gif|thumb|300px|To prevent high CMV, connect isolated source to ADC ground.]]
+
Unfortunately, there is no way around this. Windows requires confirmation from the user for driver install, even if the driver is signed.
−
ADC linearity can be adversely affected by high common-mode voltage (CMV). This can happen when the ADC is used to measure an isolated voltage source such as a battery, thermocouple, or isolated power supply. Since the source is isolated, the CMV may float up or down until it exceeds the maximum allowed CMV of the ADC's input circuitry.
+
  
−
When measuring an isolated source, be sure to connect one side of the source to the ADC power supply ground as shown in the diagram to the right. This will prevent high CMV that might othewise result in apparent non-linearity or calibration errors.{{clear}}
+
:''I'm running the setup silently, but it pops up a dialog to confirm if I want to make changes to the PC (User Account Control). How do I prevent this?''
  
−
===ADC accuracy specification===
+
Windows controls this through User Access Control.  If running the setup from a standard windows console, the Windows User Account Control (UAC) will pop-up.  This cannot be by-passed by Sensoray because the installer installs files to system directories. 
  
−
Resolution and no missing codes are both 16 bits minimum.
+
One work-around is to launch the setup in an Windows Command Prompt Window started in administrator mode (right-click and select "Run As Administrator").  Another approach is to launch the setup as a user with administrator privileges.  User access control may also be disabled, but we do not recommend this for security reasons.
  
−
{| class="wikitable"
+
====Link error====
−
!rowspan="2" style="text-align:left;"| PARAMETER
+
−
!colspan="3"| VALUE
+
−
!rowspan="2" style="text-align:left;"| UNITS
+
−
|-
+
−
! MIN
+
−
! TYP
+
−
! MAX
+
−
|-
+
−
|Integral Nonlinearity Error
+
−
|
+
−
| &plusmn;0.75
+
−
| &plusmn;1.5
+
−
| LSB
+
−
|-
+
−
| Differential Nonlinearity Error
+
−
|
+
−
| &plusmn;0.5
+
−
| &plusmn;1.25
+
−
| LSB
+
−
|-
+
−
| Gain Error
+
−
|
+
−
| &plusmn;2
+
−
| &plusmn;40
+
−
| LSB
+
−
|-
+
−
| Gain Error Temperature Drift
+
−
|
+
−
| &plusmn;0.3
+
−
|
+
−
| ppm/&deg;C
+
−
|-
+
−
| Zero Error
+
−
|
+
−
|
+
−
| &plusmn;0.8
+
−
| mV
+
−
|-
+
−
| Zero Temperature Drift
+
−
|
+
−
| &plusmn;0.3
+
−
|
+
−
| ppm/&deg;C
+
  
−
|}
+
:''I'm using VisualStudio (VS) on a 64-bit machine to build a 32-bit application for the 826. VS reports that linking failed because it can't open s826.lib. What could be the problem?''
  
−
===Maximum input voltage===
+
You should use the 32-bit DLL (and its associated LIB) because you are building a 32-bit application (x86). Use the 64-bit version only when building 64-bit apps (x64). To avoid confusion, you can copy the 32-bit DLL and its associated LIB file from the install directory to your project directory, then point the linker to it there. Make sure to also point the debugger to the 32-bit DLL by setting its working directory.
  
−
The analog inputs accept common mode voltages up to &plusmn;12V with no resulting input current or damage. CMV up to &plusmn;25V is tolerated continuously, though this will cause currents to flow in the analog inputs. CMV greater than 25V may be tolerated for brief intervals, but this can cause significant currents to flow in the analog inputs and is not specified nor guaranteed to be safe.
+
Note: You will always use the 64-bit driver on a 64-bit OS regardless of 32/64-bit application type, but you don't need to select this as it is automatically installed by the SDK installer.
  
−
==DAC==
+
====Windows 10 IoT====
  
−
===Linux Demo Sine Wave Generator counter error (-15)===
+
Sensoray has created a Universal driver (UD) for the 826 under OneCoreUAP-based editions of Windows.  It is similar to the standard driver, but compiled as [https://docs.microsoft.com/en-us/windows-hardware/drivers/what-s-new-in-driver-development#universal-windows-drivers Universal].  This driver is in our SDK zip file under the "driver/sensoray_826_universal_driver" directory.  Installation may be dependent on the specific Windows version.  The inf is Windows Universal compatible.  Sensoray does not currently have a demonstration Universal Windows App for the 826, but the .NET demo app may be portable.
  
−
The Linux sine wave generator demo may experience a timeout and exit with an error code -15 (S826_ERR_FIFOOVERFLOW).  This occurs because the priority of the demo thread may be too low for the sample time.  Linux is not a RTOS and the process (or interrupt) may be delayed and not complete the DAC output in the specified time.
+
===Linux===
  
−
Older version of the demo will exit when S826_ERR_FIFOOVERFLOW occurs.  Later versions of the demo, however, will print an error code and continue outputting the sine wave.
+
====Linux versions====
  
−
In any case, if the DAC output sampling time requirements are very small and need to be precise, it is recommended to run the process at a higher priority.  You may also consider using a low-latency or rt kernel.
+
:''Do you recommend specific Linux distributions for use with the 826?''
  
−
To run the demo at a higher priority:
+
We no longer support the obsolete kernel 2.4, but otherwise have no specific recommendation as it depends on the application (e.g., it might be desirable to use a low-latency kernel). The 826 driver is compatible with kernel versions 2.6 and higher.
  
−
"nice -n 19 ./s826demo"
+
====Troubleshooting====
  
−
For Ubuntu low-latency kernel:
+
:''The board worked yesterday but it doesn't work today. I didn't change anything. What could be the problem?''
  
−
"sudo apt-get install linux-lowlatency linux-headers-lowlatency"
+
It's likely that the operating system upgraded the Linux kernel during an automatic update. See [[Linux Troubleshooting|this appnote]] for details.
  
−
For Ubuntu rt kernel:
+
====Build errors====
  
−
"sudo apt-get install linux-rt linux-headers-rt"
+
On some Linux distributions, "<code>sudo make install</code>" may issue messages like these:
  
−
In extreme high performance cases, you may consider using the raw DAC write command (S826_DacRawWrite) instead of S826_DacDataWrite. You must make sure to understand the DAC ranges before doing so. This should normally not be necessary as S826_DacDataWrite is only marginally slower.
+
* <code>modprobe: ERROR: could not insert 's826': Required key not available</code>
 +
* <code>SSL error:02001002:system library:fopen:No such file or directory: ../crypto/bio/bss_file.c</code>
  
−
===DAC accuracy specification===
+
In such cases, it's likely that the 826 driver successfully installed and you are simply seeing a warning. You can confirm this by trying "<code>sudo modprobe s826</code>" and the 826 demo application.
  
−
Resolution and monotonicity are both 16 bits minimum.
+
=====Different gcc version=====
−
{| class="wikitable"
+
−
!rowspan="2" style="text-align:left;"| PARAMETER
+
−
!rowspan="2" style="text-align:left;"| CONDITIONS
+
−
!colspan="3"| VALUE
+
−
!rowspan="2" style="text-align:left;"| UNITS
+
−
|-
+
−
! MIN
+
−
! TYP
+
−
! MAX
+
−
|-
+
−
|Integral Nonlinearity
+
−
|
+
−
|
+
−
|
+
−
|&plusmn;2
+
−
|LSB
+
−
|-
+
−
|Differential Nonlinearity
+
−
|
+
−
|
+
−
|
+
−
|&plusmn;1
+
−
|LSB
+
−
|-
+
−
|Gain Error
+
−
|
+
−
|
+
−
|&plusmn;4
+
−
|&plusmn;20
+
−
|LSB
+
−
|-
+
−
|Gain Temperature Coefficient
+
−
|
+
−
|
+
−
|&plusmn;2
+
−
|
+
−
| ppm/&deg;C
+
−
|-
+
−
|Unipolar Zero-Scale Error
+
−
|5V unipolar range, 25&deg;C<br>10V unipolar range, 25&deg;C<br>5V unipolar range<br>10V unipolar range
+
−
|
+
−
|&plusmn;80<br>&plusmn;100<br>&plusmn;140<br>&plusmn;150
+
−
|&plusmn;200<br>&plusmn;300<br>&plusmn;400<br>&plusmn;600
+
−
|&micro;V<br>&micro;V<br>&micro;V<br>&micro;V
+
−
|-
+
−
|V_offset Temperature Coefficient
+
−
|All unipolar ranges
+
−
|
+
−
|&plusmn;2
+
−
|
+
−
|&micro;V/&deg;C
+
−
|-
+
−
|Bipolar Zero Error
+
−
|All bipolar ranges
+
−
|
+
−
|&plusmn;2
+
−
|&plusmn;12
+
−
|LSB
+
−
|}
+
  
−
==DIOs==
+
''Why do I get the following error when building the demo?"
  
−
===Generating a burst of pulses===
+
relocation R_X86_64_32S against `.bss' can not be used when making a PIE object; recompile with -fPIE
  
−
:''How can I make a DIO go active for 10ms and then inactive for another 10ms, and repeat this five times?''
+
Answer: You have a newer version of gcc, so you must rebuild the middleware. To do this, switch to the SDK downloads directory and then:
 +
* call "make lib"
 +
* cd to middleware directory: "cd middleware"
 +
* "cp *.a ../demo/"
 +
* "cd .."
  
−
There are several ways to do this but the methods you can use depend on a number of factors. Here are two general strategies:
+
Now rebuild the demo with the new .a files:
 +
* "make -C demo s826demo"
  
−
1. If high precision is not needed you can call <code>S826_DioOutputWrite()</code> multiple times, with 10ms software delays between the calls. The precision of this method depends on your operating system and system load. The code for this method is simple and straightforward.
+
==Remote access==
  
−
2. If you need precise timing then you could use two counter channels. For example, using counter channels 0 and 1:
+
:''Is there any way to use an 826 with a laptop?''
  
−
* Counter 0: Configure as PWM generator with 10ms on/off times, with external enable. Connect its enable input to counter 1's output. The goal here is for counter 0 to enable counter 1 to output pulses; counter 0 will enable the PWM generator until 5 pulses have been generated.
+
Not directly, because laptops don't provide exposed PCI Express slots. However, it is possible to locate the 826 in a host computer that does have PCIe slots and, with appropriate software, remotely access its interfaces from a laptop (e.g., via Ethernet or USB).
−
* Counter 1: Configure as event down-counter, with preload (value=5) upon enable, with external clock, with output active when counts not zero. Connect its clock input (must be external connection) to counter 0's output. The goal here is for counter 1 to count PWM pulses until it counts from 5 down to 0; it will then set its output low, thus disabling the PWM generator.
+
  
−
===Example application: I<sup>2</sup>C Emulator===
+
When designing such a system, it's important to consider that neither Ethernet nor USB are capable of real-time communication with register-based measurement and control hardware. Consequently, depending on the application, this may require the host to offload time-critical I/O functions from the laptop, such as interrupt handling, counter FIFO processing, and low-level register I/O sequences, in order to achieve real-time performance.
  
−
:''Can I use DIOs to communicate with I<sup>2</sup>C devices?''
+
Functions that are not time-critical can be implemented in various ways. For example, the host computer could run a SNMP agent process that serves as a bridge between Ethernet and the 826. To do this, you will need to create a MIB and implement the associated functions in the agent.
  
−
Have a look at [http://www.sensoray.com/downloads/appnote_826_i2c_emulator.pdf Sensoray's I<sup>2</sup>C emulator], which uses two DIOs to bit-bang an I<sup>2</sup>C bus. This open source software implements a full-featured I<sup>2</sup>C master emulator with bus arbitration and bus-hang resolver. All 826-specific code resides in a hardware abstraction layer (HAL) &mdash; an architectural feature that should exist in all production-quality software.
+
==Environmental specifications==
  
−
==Software==
+
{| class="wikitable"
 +
! style="text-align:left;"| Parameter
 +
! style="text-align:left;"| Value
 +
|-
 +
|Pressure, operating
 +
|650 to 1010 hPa
 +
|-
 +
|Humidity, operating
 +
|20% to 80% RH, non-condensing
 +
|}
  
−
===Labview===
+
==Migrating from model 626==
  
−
Before running an 826 virtual instrument (VI) under Labview, make sure you install the latest versions of the 826 DLL (s826.dll) and device driver (both are contained in the 826 SDK, which you can obtain from the ''Downloads'' tab of the [http://www.sensoray.com/products/826.htm 826 product page]). Each VI is a basically a wrapper for a DLL function and consequently the VIs are dependent on the DLL, which in turn depends on the driver. Board hardware and firmware version numbers will be automatically read from the 826 board by software when all dependencies are satisfied -- it is not necessary to manually enter any board selection information except the board number, which is specified by the board's switch settings (factory default is board number 0).
+
For users who are upgrading PCI systems to PCIe, we recommend model 826 as a replacement for model 626.
  
−
The VIs are not independently documented, but since each VI wraps a DLL function, the DLL documentation effectively explains the function of each associated VI. The DLL documentation can be found in the 826 product manual (download from the [http://www.sensoray.com/products/826.htm 826 product page] ''Documentation'' tab).
+
===Porting guide===
  
−
===Software updates===
+
A migration aid is available to help C developers port applications to model 826. The aid consists of C code which provides, when feasible, equivalent 826 API calls for 626 API functions. In cases where equivalent functions are not available, compiler errors and runtime warnings are issued, and tips are given for resolving porting issues.
  
−
1. Windows 3.3.4
+
* [http://www.sensoray.com/downloads/port626.zip 626-to-826 migration aid]
−
* C# demo application added to SDK. Error checking for invalid modes to S826_CounterModeWrite.
+
−
2. Linux 3.3.5
+
−
* C# GUI demo available, using Linux mono. To get required libraries on Ubuntu, type:
+
−
"sudo apt-get install mono-complete"
+
−
For a C# development environment, type:
+
−
"sudo apt-get install monodevelop"
+
  
−
===Resources for custom driver development===
+
===Differences between models 626 and 826===
  
−
:''I want to develop my own driver for the 826. Does Sensoray offer any resources for custom driver development?''
+
The following table compares the interfaces on the two boards:
  
−
Yes, we provide these resources free of charge:
+
{| class="wikitable"
 +
! Interface
 +
! 626
 +
! 826
 +
|-
 +
| System bus
 +
| PCI
 +
| PCI Express
 +
|-
 +
| Counters
 +
| 6 channels (3 A/B pairs)<br>24-bit resolution<br>24-bit sampling latch
 +
| 6 channels (identical)<br>32-bit resolution<br>16-deep FIFO with timestamps
 +
|-
 +
| GPIOs
 +
| 48 channels<br>40 w/edge detection (1 Msps)<br>no debounce<br>not fail-safe
 +
| 48 channels<br>48 w/edge detection (50 Msps)<br>debounce filter<br>fail-safe outputs
 +
|-
 +
| Analog out
 +
| 4 channels<br>14-bit resolution<br>20 Ksps<br>not fail-safe
 +
| 8 channels<br>16-bit resolution<br>900 Ksps<br>fail-safe outputs
 +
|-
 +
| Analog in
 +
| 16 channels<br>16-bit resolution<br>15 Ksps
 +
| 16 channels<br>16-bit resolution<br>300 Ksps
 +
|-
 +
| Watchdog timer
 +
| Single stage<br>4 shunt-selectable intervals
 +
| 3 timer stages<br>software programmable intervals
 +
|-
 +
| Fail-safe controller
 +
| n/a
 +
| Integrated
 +
|-
 +
| Timestamp generator
 +
| n/a
 +
| 32 bits, 1 &micro;s resolution
 +
|}
  
−
* '''Linux Software Development Kit (SDK)''' - Includes source code for the 826 driver and middleware, comprising a complete 826 API for Linux. The middleware core is operating system independent, which makes this SDK a great starting point for porting. The SDK can be found on the Downloads tab of the [http://www.sensoray.com/products/826.htm 826 product page]. The SDK has been carefully designed for efficient and reliable operation in multi-threaded and multi-process applications, and consequently it can be easily ported to real-time operating systems.
+
===Connector pinout differences===
−
* '''Model 826 Technical Manual''' - This comprehensive manual explains the API and 826 hardware in detail (download from the Documentation tab of the [http://www.sensoray.com/products/826.htm 826 product page]).
+
−
* '''Register Map''' - A map of the board's hardware registers is available [http://www.sensoray.com/downloads/man_826_register_map.pdf here]. The registers are accessed through PCI BAR 2. Registers appear in both banked and flat address spaces. The banked space is only required for rev 0 boards; you should use the flat space exclusively if you have a later rev, as this will yield superior performance.
+
  
−
===Linux versions===
+
:''Do models 826 and 626 have the same connectors and pinouts?''
  
−
:''Do you recommend specific Linux distributions for use with the 826?''
+
Both boards have identical connector types, and all connector pinouts are identical except for analog connector J1. Model 826 has four additional analog outputs (channels 4-7) on pins 41, 43, 45 and 47. Model 626 uses these pins as remote sense inputs for analog output channels 0-3.
 +
[[File:826 vs 626 pinouts.gif|left|350px]]
 +
{{Clear}}
  
−
We no longer support the obsolete kernel 2.4, but otherwise have no specific recommendation as it depends on the application (e.g., it might be desirable to use a low-latency kernel). We normally test first on Ubuntu LTS, but have a script to test builds on kernel versions 2.6.x, 3.x, and 4.x.
+
===Software differences===
  
−
==Cables==
+
;Driver and API
 +
Models 826 and 626 use different device drivers and APIs. The driver and API for each model is exclusive to that model and is not compatible with the other model. The drivers and APIs are necessarily different due to the expanded capabilities of model 826 and to significant hardware architecture differences between the two models. In addition, the 826 API provides blocking functions to simplify development of both event-driven and polling applications.
 +
 
 +
;Application code
 +
Since the APIs are different, it is necessary to revise application code when upgrading to model 826. Numerous examples can be found in this wiki to help in that endeavor. Also, consider using our [http://www.sensoray.com/downloads/port626.zip 626-to-826 migration aid] for C developers who are moving 626 applications to model 826.
  
 
===Using 626 cables with the 826===
 
===Using 626 cables with the 826===
Line 528: Line 547:
  
 
The 7505TDIN and 7501C are both compatible with the 826. However, we recommend using an 826C2 cable instead of the 7501C because it has a low profile header at one end that results in a denser cable stackup. That said, the 7501C cable can be used if it doesn't cause mechanical interference in your system.
 
The 7505TDIN and 7501C are both compatible with the 826. However, we recommend using an 826C2 cable instead of the 7501C because it has a low profile header at one end that results in a denser cable stackup. That said, the 7501C cable can be used if it doesn't cause mechanical interference in your system.
−
 
−
==See also==
 
−
 
−
* [[GPIO interfacing]] - design tips for DIO circuits
 
−
 
  
  
  
−
[[Category:Products]]
+
[[Category:826| ]]

Latest revision as of 08:18, 15 February 2022

Model 826 board

This is the top-level wiki page for Sensoray's model 826, a versatile analog and digital I/O system on a PCI Express board. The board has 48 digital I/Os with edge detection, sixteen 16-bit analog inputs, eight 16-bit analog outputs, six 32-bit counter channels with quadrature clock decoders, three-stage watchdog timer with fail-safe controller, and a flexible signal router.

Related pages

Each board subsystem has a dedicated wiki page:

  • ADC - analog input system
  • DACs - analog output system
  • DIOs - general-purpose digital I/Os
  • Counters - counter/timers, including appnotes for interfacing incremental encoders
  • Watchdog - watchdog timer and fail-safe controller
Please note
  • Code and circuit examples are intended to function as described, but this is not guaranteed. If you discover an error, please inform the webmaster.
  • In code examples, error checking has been simplified or omitted for clarity. It is recommended to always perform error checking in your production software.
  • C language examples depend on header file 826api.h, which should be included at the top of your source code like this: 
#include "826api.h"

Contents

[edit] Timestamp generator

The timestamp generator is a free-running 32-bit counter that serves as a time reference. The counter increments once per microsecond and overflows (to zero, without notification) every 232 µs (approximately 71.6 minutes). It is a binary counter and consequently does not keep track of the date or time-of-day. At any moment, the current count may be sampled; such a sample is called a timestamp.

A timestamp is automatically appended to every counter snapshot and to every ADC sample so that application programs can know (to within 1 µs) when each sample was acquired. Also, application programs can read the timestamp generator at any time to get a timestamp.

[edit] Usage

Timestamps are particularly useful for precisely measuring the elapsed time between hardware events. Calculation of elapsed time is easy (a single subtraction) as long as the time interval doesn't exceed 71.6 minutes. It can be used in a variety of ways, including measuring speed and capturing serial data.

If desired, an application program can directly read the current time as shown below: 

// Read the timestamp generator's current count. 
uint CurrentTimestamp(uint board)
{ 
  uint t;
  S826_TimestampRead(board, &t);
  return t;
}

The following example shows a simple application of direct timestamp reads: 

// Example: Use board0 to measure system Sleep() time.
uint t1, t0 = CurrentTimestamp(0);   // Get start time.
Sleep(25);                           // Sleep approximately 25 ms.
t1 = CurrentTimestamp(0);            // Get end time.
printf("Slept %d µs", t1 - t0);      // Display actual sleep time.

[edit] Board ID

The "BOARD NUM" switches (at top edge of board near mounting bracket) assign the board ID used by software. The ID is binary coded on the four switches and can be programmed to any value from 0 (default) to 15. A board's ID determines the corresponding bit that will be set to '1' in the value returned by S826_SystemOpen. If you have a single 826 board, the return value will be (2^ID). If you have multiple boards, the return value is the sum of (2^ID) for each board. You can enter the return value here to quickly determine its meaning.

Examples
  • You have one board with ID set to 0, so the value returned by S826_SystemOpen will be (2^0) = 1.
  • You have two boards with IDs set to 1 and 4, so the value returned by S826_SystemOpen will be (2^1)+(2^4) = 2+16 = 18.

This code snippet will tell you the meaning of the value returned by S826_SystemOpen: 

int id, flags = S826_SystemOpen();
if (flags < 0)
  printf("S826_SystemOpen returned error code %d", flags);
else if (flags == 0)
  printf("No boards were detected");
else {
  printf("Boards were detected with these IDs:");
  for (id = 0; id < 16; id++) {
    if (flags & (1 << id))
      printf(" %d", id);
  }
}

[edit] Hardware version

[edit] Reading the PWB revision

The circuit board revision (PWB rev) is visible on the solder-side of the 826 board (opposite the mounting bracket, on the bottom corner). S826_VersionRead returns the PWB rev as a numeric value with decimal range [0:31], which corresponds to a text string in the standard ASME version letter sequence. The following code shows how to convert this 32-bit value to the alphabetic revision code seen on the board: 

// Read and display version info from board 0

// Extract major_version, minor_version and build_number from a 32-bit version number:
#define VER_FIELDS(N) ((N) >> 24) & 0xFF, ((N) >> 16) & 0xFF, (N) & 0xFFFF

const char *revchar[] = {  // ASME revision sequence
  "A",  "B",  "C",  "D",  "E",  "F",  "G",  "H",
  "J",  "K",  "L",  "M",  "N",  "P",  "R",  "T",
  "U",  "V",  "W",  "Y",  "AA", "AB", "AC", "AD",
  "AE", "AF", "AG", "AH", "AJ", "AK", "AL", "AM"
};

uint api, drv, bd, fpga;
int errcode = S826_VersionRead(0, &api, &drv, &bd, &fpga);  // Read version info.
if (errcode == S826_ERR_OK) {                               // If no errors then display info:
  printf("API version    = %d.%d.%d\n", VER_FIELDS(api));   //   API major.minor.build
  printf("Driver version = %d.%d.%d\n", VER_FIELDS(drv));   //   DRVR major.minor.build
  printf("FPGA version   = %d.%d.%d\n", VER_FIELDS(fpga));  //   FPGA major.minor.build
  printf("PWB revision   = Rev %s\n",   revchar[bd & 31]);  //   PWB rev as seen on circuit board
}
else
  printf(" S826_VersionRead returned error code %d", errcode);

[edit] Rev C changes

Sensoray has developed Revision C of the 826 circuit board. This change was necessary due to the impending EOL (end-of-life) of a critical component. Specifically, the critical component (PCI Express interface chip) and FPGA were removed and replaced by a new FPGA, which absorbed the functions of the two removed components.

Applications and developers are not affected by this change

The Rev C board is fully compatible with Rev B boards and applications:

  • Mechanical attributes are unchanged, including board dimensions and placements of connectors, switches, indicator LEDs, and hold-down bracket.
  • Connector pinouts, electrical and timing specifications are unchanged.
  • Rev C is 100% software compatible with Rev B on all software layers: application, API and driver (including user-developed drivers and APIs for RTOS, etc.).

Rev B and Rev C boards can be used interchangeably in new and existing applications. From an application's perspective, the only detectable differences between Rev B and Rev C boards are the version numbers returned by the API function S826_VersionRead():

  • S826_VersionRead() will report the PWB version as Rev B or Rev C as appropriate for the board's hardware version.
  • S826_VersionRead() will report FPGA version 0.0.70 or higher for Rev C boards, or version 0.0.69 or lower for Rev B boards.

[edit] Connector pinouts

The following drawings show the pinouts of the board's header connectors as viewed from the top (component) side of the circuit board:

  • 826 pinout J1.gif
  • 826 pinout J2.gif
  • 826 pinout J3.gif
  • 826 pinout J4.gif
  • 826 pinout J5.gif
  • 826 pinout P2.gif

[edit] Software

[edit] C examples

A variety of C programming examples have been collected together in a common source file to illustrate how to program resources on the 826.

[edit] VB.NET demo

To help you jump-start your project, we offer the VB.NET demo for model 826. This demo program provides a pre-built Windows executable with a GUI for nearly every hardware resource on the board. All source files are provided, along with a VisualStudio project.

[edit] Programming in C#

Each 826 SDK includes a C# demo application. These demos show how to call API functions from C#, and can serve as a useful starting point for a custom application.

[edit] Linux demo

In the Linux SDK, a C# GUI demo is available which uses Linux mono. To get the required libraries on Ubuntu, type: 

"sudo apt-get install mono-complete"

For a C# development environment, type: 

"sudo apt-get install monodevelop"

[edit] Pointer arguments

Many of the API functions have pointer arguments. This is no problem for C#, which allows you to pass function arguments by reference. To see how this is done, consider the S826_AdcEnableRead function:

The C prototype is: 

int S826_AdcEnableRead(unsigned int board, unsigned int *enable);

So in C# you should declare the function this way: 

[DllImport("s826.dll", CallingConvention = CallingConvention.StdCall)]
static extern Int32 S826_AdcEnableRead(UInt32 board, ref UInt32 enable);

Now you can call the function this way: 

Uint32 isEnabled;
Int32 errcode = S826_AdcEnableRead(0, ref isEnabled);

[edit] Labview

Before running an 826 virtual instrument (VI) under Labview, make sure you install the latest versions of the 826 DLL (s826.dll) and device driver (both are contained in the 826 SDK, which you can obtain from the Downloads tab of the 826 product page).

Each VI is a basically a wrapper for a DLL function and consequently the VIs are dependent on the DLL, which in turn depends on the driver. Board hardware and firmware version numbers will be automatically read from the 826 board by software when all dependencies are satisfied -- it is not necessary to manually enter any board selection information except the board number, which is specified by the board's switch settings (factory default is board number 0).

The VIs are not independently documented, but since each VI wraps a DLL function, the DLL documentation effectively explains the function of each associated VI. The DLL documentation can be found in the 826 product manual (download from the 826 product page Documentation tab).

The VIs may be installed under Labview's instrument library (e.g., "instr.lib\Sensoray 826") or elsewhere if desired. Refer to Labview documentation for information about paths and other relevant topics.

[edit] Matlab

To use an 826 with Matlab you must first install the latest 64-bit versions of the 826 API (s826.dll) and device driver; these are both part of the 826 SDK, which you can obtain from the Downloads tab of the 826 product page. You may then use Matlab's loadlibrary() function to enable access to the API, and calllib() to call API functions. The API functions are described in the 826 product manual, which can be found on the 826 product page Documentation tab. The following example illustrates how this works.

Note: Matlab cannot execute loadlibrary() unless a compatible C compiler is installed on your computer. If Matlab complains about an "Error using loadlibrary" because "No supported compiler was found" then you must download and install one of the Matlab-compatible compilers (e.g., MinGW-w64) to resolve this issue. Please consult Mathworks for a list of compatible compilers. 

% Simple Matlab example: turn on general-purpose digital I/O 2 ***************************

% Change these values as required:
hdrPath = 'C:\Sensoray\826api.h';           % Path to API header
dllPath = 'C:\Windows\System32\s826.dll';   % Path to API executable
board = 0;                                  % Use 826 board #0 (i.e., board w/ID switches set to 0)

loadlibrary(dllPath, hdrPath, 'alias', 's826');     % Load the API.
boardflags = calllib('s826', 'S826_SystemOpen');    % Open API and detect all boards.
if (boardflags < 0)                                 % If API failed to open
    disp("S826_SystemOpen error");                  %   Report error.
else                                                % Else
    if (boardflags ~= bitshift(1, board))           %   If board #0 was not detected
        disp("Failed to detect 826 board");         %     Report error (check board's switch settings).
    else                                            %   Else ...
        buf = libpointer('uint32Ptr', [6 0]);       %     Allocate buffer for DIO state data.
        errcode = calllib('s826', ...               %     Turn on DIO1 and DIO2.
            'S826_DioOutputWrite', board, buf, 0);
        clear buf;                                  %     Free buffer.
        if (errcode ~= S826_ERR_OK)
            disp('DIO write problem')               %     Report error if DIO write failed.
        end
    end
    errcode = calllib('s826', 'S826_SystemClose');  %   Close API.
end
unloadlibrary s826;                                 % Unload the API.

[edit] Matlab SDK

Sensoray offers an open-source software development kit for Matlab programmers, which you can obtain from the Downloads tab of the 826 product page. The Matlab SDK includes two files:

  • s826.m is a class that defines useful constants and provides wrappers for all 826 API functions. Include this file in any project that interacts with model 826 boards.
  • s826_demo.m is a short program that demonstrates how to use the s826 class.

[edit] ROS (Robot Operating System)

Sensoray SDKs do not include a ROS package, but the Linux SDK has everything needed to create one. The simplest way to use ROS with model 826 is to install the Linux 826 device driver and API (shared library), and then call the API functions as shown in the following example. Note that this example is coded in C++, but you can easily call the API functions from Python or any other language. 

///////////////////////////////////////////////////////////////////////////////////////////////////////////
// Simple ROS (Robot Operating System) example for Sensoray 826 PCI Express analog/digital IO board.
// Function: Publishes 16 analog inputs 10 times per second
///////////////////////////////////////////////////////////////////////////////////////////////////////////

#define X826(func)    if ((errcode = (func)) != S826_ERR_OK) { printf("\nERROR: %d\n", errcode); return; }    // Call function and process error

int PublishAINChannels()
{
    int adcbuf[16];     // adc data buffer
    uint slotlist;      // timeslot flags
    uint slot;          // timeslot index (and ain channel number)
    uint board = 0;     // board ID
    int errcode;

    // Initialize data array for publisher
    std_msgs::Int16MultiArray data_array;
    data_array.layout.dim.push_back(std_msgs::MultiArrayDimension());
    data_array.layout.dim[0].label = "board-" + to_string(board) + " AIN";
    data_array.layout.dim[0].size = 16;
    data_array.layout.dim[0].stride = 1;
    data_array.layout.data_offset = 0;
   
    // Configure adc and start it running.
    for (slot = 0; slot < 16, slot++ )                          // Configure slots: chan = slot number, settle time = 20 us, range = +/-10 V
        X826(S826_AdcSlotConfigWrite(board, slot, slot, 20, S826_ADC_GAIN_1));
    X826(S826_AdcSlotlistWrite(board, 0xFFFF, S826_BITWRITE));  // Enable all slots.
    X826(S826_AdcTrigModeWrite(board, 0));                      // Select continuous trigger mode.
    X826(S826_AdcEnableWrite(board, 1));                        // Start conversions.

    ROS_INFO("\tPublishing AIN Channels");

    ros::Rate loop_rate(10);

    while (ros::ok())
    {
        // Wait for next publish time. This is at top of loop so first ADC burst will complete before we try to read the data.
        // Otherwise we might get bogus data the first time through the loop.
        loop_rate.sleep();

        // Fetch ADC data
        data_array.data.clear();
        slotlist = 0xFFFF; // from all 16 slots
        errcode = S826_AdcRead(board, adcbuf, NULL, &slotlist, 0);

        // Handle errors
        if ((errcode != S826_ERR_OK) && (errcode != S826_ERR_MISSEDTRIG)) {  // this app doesn't care about adc missed triggers
            printf("\nERROR: %d\n", errcode);
            break;
        }

        // Publish ADC data
        for (slot = 0; slot < 16; slot++) {
            // Publishing raw data (16-bit signed int). Convert to +/-10V by multiplying by 10/32768.
            // example: cout << (double)(data_array.data[i] * 10) / 32768 << endl;
            data_array.data.push_back((short)(adcbuf[slot] & 0xFFFF));
        }
        analog_input_pub.publish(data_array);
    }

    S826_AdcEnableWrite(board, 0);          // Halt conversions.
    return errcode;
}

[edit] Resources for custom driver development

826 software stack. The generic API is portable — to port, simply adapt the Linux driver and HAL for your OS/RTOS.
I want to develop my own device driver for the 826. Does Sensoray offer any resources for custom driver development?

Yes, we provide these resources free of charge:

  • Linux Software Development Kit (SDK) - Includes source code for the 826 driver, hardware abstraction layer (HAL) and API middleware, comprising a complete 826 software stack for Linux. The generic API is operating system independent and thread-safe, which makes this SDK a great starting point for porting to any operating system. The stack has been carefully designed for reliable operation in and for easy porting to real-time operating systems. The SDK can be found on the Downloads tab of the 826 product page.
  • Model 826 Technical Manual - This comprehensive manual explains the API and 826 hardware in detail (download from the Documentation tab of the 826 product page).
  • Register Map - A map of the board's hardware registers is available here. The registers are accessed through PCI BAR 2. Registers appear in both banked and flat address spaces. The banked space is only required for rev 0 boards; you should use the flat space exclusively if you have a later rev, as this will yield superior performance.

[edit] Software updates

1. Windows 3.3.4

  • C# demo application added to SDK. Error checking for invalid modes to S826_CounterModeWrite.

2. Linux 3.3.5

  • C# GUI demo available, using Linux mono.

[edit] Windows

[edit] Custom installation and re-distribution

Sensoray's installer uses the Nullsoft Scriptable Install System (NSIS). It is created from a .NSI script. The core API is installed as follows in NSI script code: 

Section "Core API"
SectionIn RO
${If} ${RunningX64}
 SetOutPath "$WINDIR\system32";
 !insertmacro  DisableX64FSRedirection
 File "..\mid-826\code\Release64\s826.dll";
 !insertmacro  EnableX64FSRedirection
 SetOutPath "$WINDIR\SysWOW64";
 File "..\mid-826\code\Release\s826.dll";
${Else}
 SetOutPath "$WINDIR\system32";
 File "..\mid-826\code\Release\s826.dll";
${EndIf}
SectionEnd

The drivers are installed via dpinst.exe in the NSI script as follows: 

Section "Drivers"
SectionIn RO
CreateDirectory "$INSTDIR\driver\x64";
SetOutPath "$INSTDIR\driver\x64";
File "..\cd\driver\x64\dpinst.exe";
File "..\cd\driver\x64\s826.cat";
File "..\cd\driver\x64\s826.inf";
File "..\cd\driver\x64\s826.sys";
File "..\cd\driver\x64\s826filter.cat";
File "..\cd\driver\x64\s826filter.inf";
File "..\cd\driver\x64\s826filter.sys";
File "..\cd\driver\x64\WdfCoInstaller01009.dll";
CreateDirectory "$INSTDIR\driver\x32";
SetOutPath "$INSTDIR\driver\x32";
File "..\cd\driver\x32\dpinst.exe";
File "..\cd\driver\x32\s826.cat";
File "..\cd\driver\x32\s826.inf";
File "..\cd\driver\x32\s826.sys";
File "..\cd\driver\x32\s826filter.cat";
File "..\cd\driver\x32\s826filter.inf";
File "..\cd\driver\x32\s826filter.sys";
File "..\cd\driver\x32\WdfCoInstaller01009.dll";
MessageBox MB_OK "Driver installation dialog will pop-up. Follow the prompts and click Finish when done"
${If} ${RunningX64}
 ExecWait '"$INSTDIR\driver\x64\dpinst.exe" /f'
${Else}
 ExecWait '"$INSTDIR\driver\x32\dpinst.exe" /f'
${EndIf}
NoInstallDriver:
SectionEnd
What other libraries does the installer install as part of the Core API?

The 826 is compiled with Microsoft Visual Studio C++ 2008. The re-distributables for C++ must be installed. The installer installs this library silently running the command: 

"vcredist_x86.exe /q"

and the following additional command on 64-bit systems: 

"vcredist_x64.exe /q"

These re-distributables are available from Microsoft for x64 and x86.

Are any other libraries required? I installed the libraries above, but the demo doesn't work with my custom installer?

The demo is written using .NET libraries (version 3.5). These are also available from Microsoft here. The executable can be silently installed using this command: 

"dotnetfx35setup.exe /qb"
Could I obtain the full 826 NSI script as a template for creating my own installer?

Yes, the full script is available here.

[edit] Silent install

I want to run the installer silently. Do you have any way to do this?

There are many options. For re-distribution, you may create your own installation package. Also, starting with version 3.3.9, there are additional command line options to quiet the setup.exe installer from command line or batch file. These options are described below.

What are the options for silent install?

The basic silent install is invoked by running the following command from command line or batch script: 

"setup.exe /S"

Please note that the /S is case sensitive and must be upper case.

I've pre-installed the drivers and don't want to re-install them during the installation? Is there a command for that? 
"setup.exe /S /no_driver=1"
Is there an additional command to not install the demo programs?

Yes, in version 3.3.9, the following command will install the required DLLs and system libraries, but no drivers or demo programs. 

"setup.exe /S /no_driver=1 /no_demos=1"
I want to install the drivers silently, but there is always a pop-up to verify.

Unfortunately, there is no way around this. Windows requires confirmation from the user for driver install, even if the driver is signed.

I'm running the setup silently, but it pops up a dialog to confirm if I want to make changes to the PC (User Account Control). How do I prevent this?

Windows controls this through User Access Control. If running the setup from a standard windows console, the Windows User Account Control (UAC) will pop-up. This cannot be by-passed by Sensoray because the installer installs files to system directories.

One work-around is to launch the setup in an Windows Command Prompt Window started in administrator mode (right-click and select "Run As Administrator"). Another approach is to launch the setup as a user with administrator privileges. User access control may also be disabled, but we do not recommend this for security reasons.

[edit] Link error

I'm using VisualStudio (VS) on a 64-bit machine to build a 32-bit application for the 826. VS reports that linking failed because it can't open s826.lib. What could be the problem?

You should use the 32-bit DLL (and its associated LIB) because you are building a 32-bit application (x86). Use the 64-bit version only when building 64-bit apps (x64). To avoid confusion, you can copy the 32-bit DLL and its associated LIB file from the install directory to your project directory, then point the linker to it there. Make sure to also point the debugger to the 32-bit DLL by setting its working directory.

Note: You will always use the 64-bit driver on a 64-bit OS regardless of 32/64-bit application type, but you don't need to select this as it is automatically installed by the SDK installer.

[edit] Windows 10 IoT

Sensoray has created a Universal driver (UD) for the 826 under OneCoreUAP-based editions of Windows. It is similar to the standard driver, but compiled as Universal. This driver is in our SDK zip file under the "driver/sensoray_826_universal_driver" directory. Installation may be dependent on the specific Windows version. The inf is Windows Universal compatible. Sensoray does not currently have a demonstration Universal Windows App for the 826, but the .NET demo app may be portable.

[edit] Linux

[edit] Linux versions

Do you recommend specific Linux distributions for use with the 826?

We no longer support the obsolete kernel 2.4, but otherwise have no specific recommendation as it depends on the application (e.g., it might be desirable to use a low-latency kernel). The 826 driver is compatible with kernel versions 2.6 and higher.

[edit] Troubleshooting

The board worked yesterday but it doesn't work today. I didn't change anything. What could be the problem?

It's likely that the operating system upgraded the Linux kernel during an automatic update. See this appnote for details.

[edit] Build errors

On some Linux distributions, "sudo make install" may issue messages like these:

  • modprobe: ERROR: could not insert 's826': Required key not available
  • SSL error:02001002:system library:fopen:No such file or directory: ../crypto/bio/bss_file.c

In such cases, it's likely that the 826 driver successfully installed and you are simply seeing a warning. You can confirm this by trying "sudo modprobe s826" and the 826 demo application.

[edit] Different gcc version

Why do I get the following error when building the demo?" 

relocation R_X86_64_32S against `.bss' can not be used when making a PIE object; recompile with -fPIE

Answer: You have a newer version of gcc, so you must rebuild the middleware. To do this, switch to the SDK downloads directory and then:

  • call "make lib"
  • cd to middleware directory: "cd middleware"
  • "cp *.a ../demo/"
  • "cd .."

Now rebuild the demo with the new .a files:

  • "make -C demo s826demo"

[edit] Remote access

Is there any way to use an 826 with a laptop?

Not directly, because laptops don't provide exposed PCI Express slots. However, it is possible to locate the 826 in a host computer that does have PCIe slots and, with appropriate software, remotely access its interfaces from a laptop (e.g., via Ethernet or USB).

When designing such a system, it's important to consider that neither Ethernet nor USB are capable of real-time communication with register-based measurement and control hardware. Consequently, depending on the application, this may require the host to offload time-critical I/O functions from the laptop, such as interrupt handling, counter FIFO processing, and low-level register I/O sequences, in order to achieve real-time performance.

Functions that are not time-critical can be implemented in various ways. For example, the host computer could run a SNMP agent process that serves as a bridge between Ethernet and the 826. To do this, you will need to create a MIB and implement the associated functions in the agent.

[edit] Environmental specifications

Parameter Value
Pressure, operating 650 to 1010 hPa
Humidity, operating 20% to 80% RH, non-condensing

[edit] Migrating from model 626

For users who are upgrading PCI systems to PCIe, we recommend model 826 as a replacement for model 626.

[edit] Porting guide

A migration aid is available to help C developers port applications to model 826. The aid consists of C code which provides, when feasible, equivalent 826 API calls for 626 API functions. In cases where equivalent functions are not available, compiler errors and runtime warnings are issued, and tips are given for resolving porting issues.

[edit] Differences between models 626 and 826

The following table compares the interfaces on the two boards:

Interface 626 826
System bus PCI PCI Express
Counters 6 channels (3 A/B pairs)
24-bit resolution
24-bit sampling latch 		6 channels (identical)
32-bit resolution
16-deep FIFO with timestamps
GPIOs 48 channels
40 w/edge detection (1 Msps)
no debounce
not fail-safe 		48 channels
48 w/edge detection (50 Msps)
debounce filter
fail-safe outputs
Analog out 4 channels
14-bit resolution
20 Ksps
not fail-safe 		8 channels
16-bit resolution
900 Ksps
fail-safe outputs
Analog in 16 channels
16-bit resolution
15 Ksps 		16 channels
16-bit resolution
300 Ksps
Watchdog timer Single stage
4 shunt-selectable intervals 		3 timer stages
software programmable intervals
Fail-safe controller n/a Integrated
Timestamp generator n/a 32 bits, 1 µs resolution

[edit] Connector pinout differences

Do models 826 and 626 have the same connectors and pinouts?

Both boards have identical connector types, and all connector pinouts are identical except for analog connector J1. Model 826 has four additional analog outputs (channels 4-7) on pins 41, 43, 45 and 47. Model 626 uses these pins as remote sense inputs for analog output channels 0-3.

826 vs 626 pinouts.gif

[edit] Software differences

Driver and API

Models 826 and 626 use different device drivers and APIs. The driver and API for each model is exclusive to that model and is not compatible with the other model. The drivers and APIs are necessarily different due to the expanded capabilities of model 826 and to significant hardware architecture differences between the two models. In addition, the 826 API provides blocking functions to simplify development of both event-driven and polling applications.

Application code

Since the APIs are different, it is necessary to revise application code when upgrading to model 826. Numerous examples can be found in this wiki to help in that endeavor. Also, consider using our 626-to-826 migration aid for C developers who are moving 626 applications to model 826.

[edit] Using 626 cables with the 826

I have a 7505TDIN breakout board and 7501C1 (50-pin cable) for the 626. Can I use these with the 826?

The 7505TDIN and 7501C are both compatible with the 826. However, we recommend using an 826C2 cable instead of the 7501C because it has a low profile header at one end that results in a denser cable stackup. That said, the 7501C cable can be used if it doesn't cause mechanical interference in your system.

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