PLC RTD temperature measurement

Simple PLC RTD temperature measurement

4-20mA PLC PT100 RTD temperature measurement

The Robert Owen Inc. ROI-XMA 4-20mA sensor transmitter allows 4-20mA PLC inputs to be used for RTD temperature measurement. 

Robert Owen Inc. temperature transmitters offer temperature ranges as wide as -200 to 500 Deg C or as small as 0 to 32 Deg C, depending on the make and model. The ROI-XMA RTD 4-20mA Temperature Transmitter works with standard PT100 platinum 100-ohm RTDs and converts the resistance to 4-20mA current loop format, making the measurement suitable for long distance transmission.

With ROI-XMA; you can use either PT100 or PT1000 RTDs with standard industrial PLC’s and industrial I/O. ROI-XMA series of loop powered RTD transmitters, convert an RTDs temperature related resistance change into a standard 4-20mA instrumentation signal.

Input RTD temperature sensor data, into your PLC; using standard 4-20mA, 0-20mA, 0-5Vdc, or 0-10Vdc input A-D channels. No need to replace working sensors, you can signal condition your sensors to make them compatible with most modern industrial control systems.

RTDs are inexpensive and are not polarity dependent. So easy to connect and replace them if damaged. Because RTDs are resistive devices, you can easily verify if it’s working with a standard ohm meter and the heat change by holding it, which is a great feature.

Because they are based on current, you can connect 4-20mA transmitters over long distances to a PLC. Using a standard 24Vdc power source and a 22Awg cable can connect a 4-20mA transmitter over 1,000 feet away. It’s surprising how rapidly the length of a cable increases, when you try to run it neat and out of the way.

ROI-XMAs Feature:

  • Pluggable sensor Euro connectors
  • Snap on mounting base for DIN rail or surface mounting.
  • Loop powered sensor transmitter, signal conditioner format

They are so useful for interfacing existing systems. Such as HVAC and refrigeration systems with built in RTD temperature sensors. For example, makes them compatible with modern industrial control systems. Accessories such as signal isolators and trend recorders are available.


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