Analog sensor signal conditioning
Convert thermistor and potentiometer sensors into the 4-20mA signal your PLC already reads. Two wires in, two wires out, and a spare analog input becomes a temperature or position measurement.
Use the spare analog input you already have
Signal conditioners are a simple solution when your PLC has a spare 4-20mA, 5 V or 10 V analog channel. The conditioner’s output matches that input, so the channel can measure a sensor it could not read directly.
ROI-XMA transmitters read industry-standard NTC thermistors and potentiometers. Existing sensors connect to modern control systems without replacing them, saving time and money.
- PLC compatible 4-20mA output, loop powered
- Two-wire input and output for simple wiring
- Snap-on base for 35 mm DIN rail or surface mounting
- Wide loop supply from 7.5 to 36 V DC
General specifications
- Output
- 4-20mA, loop powered, 2-wire
- Supply
- 7.5 to 36 V DC
- Thermistor input
- 10K ohm NTC @ 25 °C
- Response
- 10 ms
- Connections
- 30–12 AWG wire
- Mounting
- 35 mm DIN rail or surface, snap-on base
- Dimensions
- 4.510 × 1.258 × 3.948 in (L × W × H above rail)
The mated connector adds 3/8 in to the height. A loop termination resistor is required when used with a voltage ADC.
Two sensor types, one simple approach
Temperature: NTC thermistors
Measure 10K NTC thermistor temperature sensors on a spare PLC analog channel. Thermistors suit limited temperature ranges, where they can achieve higher precision than other temperature sensors.
Thermistor transmitter ranges →Position: potentiometers
Measure potentiometer position sensors on a spare PLC analog channel, for valve position, level floats, linear and rotary travel.
Potentiometer transmitters →NTC thermistor 4-20mA transmitters
Standard 10K NTC versions are listed below. Versions can be built for thermistors from 1K to 100K ohm at 25 °C, and the output can be scaled to a custom span within the sensor range.
| Range | Sensor | Output | Details |
|---|---|---|---|
| −10 to 50 °C | 10K NTC | 4-20mA | View transmitter |
| 0 to 50 °C | 10K NTC | 4-20mA | View transmitter |
| −10 to 75 °C | 10K NTC | 4-20mA | View transmitter |
| 0 to 75 °C | 10K NTC | 4-20mA | View transmitter |
Simple to wire
There are only two wires to connect for the input and two for the output. The 4-20mA output is wired in series with the loop supply and the measuring device, and the transmitter draws its power from the loop.
To read the signal on a 5 V or 10 V voltage input, add a loop termination resistor across the input.
Where it is used
- HVAC systems
- Refrigeration and chillers
- Computer room monitoring
- Environmental monitoring
- Dryers and other industrial applications
Add a sensor to a PLC
- Choose the transmitter for your sensor and range.
- Wire the sensor to the two input terminals.
- Wire the loop in series with the supply and a spare PLC analog input.
- Scale the 4–20 mA signal to engineering units in the PLC.
Related solutions
Multi-Channel Distributed Temperature Measurement
Many thermistor transmitters, ROI-IOM nodes and one RS-485 cable to a PC or PLC.
Learn more →4-20mA to Modbus RS-485 enclosure
Read up to four transmitters on a PC, ready-wired in an enclosure.
Learn more →Need to condition a sensor signal?
Tell us the sensor, the range and what it connects to. Custom ranges and other thermistor values are available.