Features
- Measures thermocouple, RTD, strain gage, voltage, 4-20 mA, thermistor, and resistance
- 8 or 16 sensor channels with differential inputs
- Provides excitation to passive sensors
- Pulsed sensor excitation minimizes sensor self-heating
- Cold-junction compensation for thermocouples
- Each channel configurable for any supported sensor type
- Fully electronic calibration
The SENSORAY Models 7418/19 offer a cost-effective way to acquire sensor data for any STD bus system. They features 16-bit resolution from 8 or 16 channels, each individually programmable for a different sensor type. Analog-to-digital conversion is performed in under 22 milliseconds, providing 45 channels per second scan rate.
The 7418/19 adapter boards plug directly into any STD bus computer. Linearization, calibration, and sensitivity are software programmable, eliminating trim potentiometers and the need for board access. Sensor field wiring is accomplished with a 40-conductor flat cable and remotely mountable screw- termination board, either model 7409TB or model 7409TDIN with DIN rail mounting hardware.
Calibration
Models 7418/19 automatically self-calibrate by measuring internal precision references. Reference data is stored in EEPROM so the adapter board may be easily interchanged. Signal conditioning is provided for thermistors, RTD’s, thermocouples, strain and pressure, resistance and voltage inputs. Standard correction for nonlinear sensors is built in. Custom compensation can be downloaded.
Excitation
A pulsed constant-voltage source is provided for strain and pressure sensors. A pulsed constant-current source is provided for resistive sensors. Lead loss errors from RTD’s, thermistors, and resistors are eliminated with the use of a four-wire circuit.
An on-board microprocessor continually scans the active sensor channels. Each channel is amplified, digitized, filtered, converted to engineering units, and stored in on-board memory. This process is independent of host CPU activity.
Specifications
| Input resistance |
100 MΩ |
| Maximum input voltage |
63 VAC rms |
| CMMR |
95 db/min |
| Maximum command mode |
±5 V |
| A/D converter |
16-bit integrating |
| Conversion time |
22 ms/channel |
| A/D scan rate |
45 samples/second |
| Operating temperature |
-25 to 70 °C |
| Interface |
STD 80 |
| Input power |
5 V (at 100 mA)
12 V (at 45 mA) |
| Dimensions |
(W x H): 4.40 x 6.90 inches |
| Sensor Types |
|---|
| Thermocouples |
J, K, T, S, E, B, N, C, R |
| Platinum RTD |
100 Ω, types 385 and 392 |
| Nickel RTD |
120, 200, 1000 Ω |
| Copper |
10 Ω |
| Thermistors |
10000 Ω, YSI types 44006 or 44031 |
| Strain gauges |
120 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 |