4-20mA Sensor Transmitters for PLC Monitoring
Connect industry-standard sensors to PLC, RTU, and monitoring systems using ROI loop-powered 4-20mA sensor transmitters. The ROI Series provides a simple interface for adding sensor measurements to industrial, HVAC, refrigeration, environmental, and remote monitoring systems.
Connect sensors to standard 4-20mA monitoring systems
The ROI Series is a versatile family of loop-powered 4-20mA sensor transmitters designed to interface industry-standard sensors with modern measurement and control systems.
When spare PLC 4-20mA inputs are available, an ROI transmitter provides a straightforward way to add sensor measurement using the standard industrial 4-20mA signal.
- 4-20mA loop powered — standard two-wire industrial measurement signal
- Industry-standard sensors — interface supported sensors with PLC and monitoring equipment
- Scalable signal range — signal range can be scaled to alternate spans within the sensor range
- Flexible mounting — 35 mm DIN rail or surface-mountable snap-on base
4-20mA Transmitter Capabilities
- Loop-powered 4-20mA signal output
- Wide 4-20mA loop supply range
- 35 mm DIN-rail mounting
- Surface-mountable snap-on base
- Euro-style electrical connectors
- 30-12 AWG wire connections
- Part-number-dependent factory-set input range
- Thermistor input
4-20mA Sensor Transmitter Specifications
Loop-Powered 4-20mA Signal Output
The ROI sensor transmitter provides a loop-powered 4-20mA output using a two-wire connection. The transmitter output connects in series with the loop supply and measurement device.
- Signal output: 4-20mA loop powered
- Two-wire 4-20mA connection
- Wide 4-20mA loop supply range
- Suitable for remote monitoring applications
Measure Industry-Standard Sensors
ROI 4-20mA sensor transmitters provide an interface between supported sensor inputs and standard industrial 4-20mA measurement systems.
- Input type: thermistor
- Input range: part-number dependent and factory set
- Signal range scalable to alternate spans within sensor range
DIN-Rail or Surface Mounting
The transmitter uses a mounting base that can be installed on standard 35 mm DIN rail or used as a surface-mountable snap-on base.
- 35 mm DIN-rail mounting
- Surface-mountable snap-on base
- Euro-style electrical connectors
- 30-12 AWG wire connections
Use Existing 4-20mA Inputs for Sensor Measurement
ROI 4-20mA sensor transmitters allow supported sensors to connect to equipment that already accepts the industry-standard 4-20mA measurement signal.
This provides a practical approach for adding sensor measurements to systems with available PLC, RTU, PC analog-to-digital, or other compatible measurement inputs.
Sensor Measurement Path
- Connect the sensor — connect the supported sensor to the appropriate ROI transmitter.
- Transmit the measurement — the transmitter provides a standard loop-powered 4-20mA signal representing the sensor measurement.
- Read the signal — connect the current loop to a PLC, RTU, PC A-D system, or compatible measurement device.
4-20mA Sensor Monitoring Applications
HVAC and Refrigeration
Add sensor measurements to HVAC systems, refrigeration equipment, chillers, and other temperature-monitoring applications using standard 4-20mA inputs.
Environmental Monitoring
Connect remote sensors to industrial monitoring equipment using the widely used 4-20mA current-loop measurement signal.
PLC Sensor Monitoring
Use available PLC 4-20mA analog inputs to add sensor measurements without requiring a separate sensor-specific measurement system.
Connect to Industrial Measurement Equipment
The standard 4-20mA output allows ROI sensor transmitters to interface with compatible PLC, RTU, PC analog-to-digital, and other industrial measurement systems.
Voltage-input measurement systems may also be used with an appropriate loop termination resistor to convert the loop current into a measurable voltage.
Compatible Measurement Approaches
- PLC 4-20mA analog inputs
- RTU current inputs
- PC analog-to-digital measurement systems
- 20mA measurement systems
- 5 V measurement systems with loop termination resistor
- 10 V measurement systems with loop termination resistor
Related Sensor Solutions
Sensor Signal Conditioning
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Sensor Data Acquisition
Connect sensor measurements with software and data-acquisition systems for monitoring and application-specific solutions.
Need a 4-20mA Sensor Transmitter?
Tell Robert Owen what sensor you need to measure and what equipment will receive the signal. We can help determine the appropriate sensor interface, signal conditioning, and measurement approach for your application.
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