8/16-channel smart sensor interface | Model 418/419

Model 418 8/16-channel smart sensor interface
  • Measures thermocouples, RTDs, strain gages, thermistors, 4-20 mA, voltage and resistance
  • 8 high-accuracy differential input channels
  • Integral sensor excitation
  • Exclusive pulsed excitation minimizes sensor self-heating
  • Configurable sensor type per channel
  • Fully electronic calibration

Model 418/419 is a legacy product and is not recommended for new designs. Legacy products are available but may have lead times up to 12 weeks and minimum order requirements. Use our Product Finder to find a comparable product or contact our Design Support Team.


Sensoray models 418 and 419 offer an easy and cost-effective way to acquire sensor data for any ISA bus system. They feature 16-bit resolution from 8 or 16 channels, each individually programmable for different sensor types.

An on-board microcomputer continually scans the active sensor channels. Each channel is amplified, digitized, filtered, linearized, converted to engineering units, and stored in on-board memory, all independent of host CPU activity. Analog to digital conversion is performed in under 22 milliseconds, providing 45 channels per second scan rate.

A pulsed constant-voltage source is provided for strain and pressure sensors, and a pulsed constant-current source is provided for resistive sensors, thus minimizing sensor self-heating. Lead loss errors from RTD's, thermistors, and resistors are eliminated with the use of a four-wire circuit.

The boards plug directly into standard ISA bus slots. Sensor field wiring is accomplished with a 37-conductor flat cable and remotely mountable screw-termination board, either model 7409TB or model 7409TDIN with DIN rail mounting hardware.

Model 418 / 419 application



Precision reference standards are periodically sampled and used to eliminate gain and offset errors from sensor measurements. Signal conditioning is provided for thermistors, RTD's, thermocouples, strain and pressure, resistance and voltage inputs.

Calibration data is stored in EEPROM so the adapter board may be easily interchanged. Calibration is fully electronic — physical trimpots have been eliminated, along with the need for board access during recalibration.


Input resistance100 MΩ
Maximum input voltage63 VAC rms
CMMR95 db/min
Maximum command mode±5 V
A/D converter16-bit integrating
Conversion time22 ms/channel
A/D scan rate45 samples/second
Operating temperature-25 to 70 °C
PC/104 interface2 I/O ports
Input power5 V (at 100 mA)
12 V (at 45 mA)
Sensor Types
ThermocouplesJ, K, T, S, E, B, N, C, R
Platinum RTD100 Ω, types 385 and 392
Nickel RTD120, 200, 1000 Ω
Copper10 Ω
Thermistors10000 Ω, YSI type 44006 or 44031
Strain gauges120 to 4000 Ω
Sensor Resolution Range
Thermocouples 0.1 °C -270 to 1760 °C
Thermistors 0.01 °C -55 to 145 °C
Resistors 0.02 Ω
0.125 Ω
31 Ω
0 to 400 Ω
0 to 3 kΩ
0 to 600 kΩ
RTDs 0.05 °C
0.0125 °C
-200 to 800 °C
0 to 400 °C
Strain/pressure 5 µV ±100 mV
DC voltage 5 µV
20 µV
200 µV
±100 mV
±500 mV
±5 V


File Version Type Size
Model 418/419 Instruction Manual1.0.0PDF167 KB


File Version Type Size
Smart A/D Software Development Kit1.0.2ZIP243 KB
Other Operating Systems
Need a software development kit for another operating system? We can port our SDK to
your OS or provide the information you need to do it yourself. Contact Sales for details.

Pricing & Ordering

Model Description Qty 1 Qty 2-9 Order Qty.
4188-channel smart sensor interfaceCallCall 
41916-channel smart sensor interfaceCallCall 
Termination boards
7409TBBreakout board, 40-pin, with temperature sensor$72$65
7409TCBreakout board, 40-pin, with temperature sensor and prototyping area$113$103
7409TDINBreakout Board, 40-pin, with temperature sensor and prototype area, DIN mountable$151$135
7409CCable, flat, 40 conductor, 18 inches$21$20
7409C1Cable, flat, 40 conductor, 1 meter$31$28

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