How to connect a sensor with 4-20mA output to a Datalogger/PLC

Sensors with output in 4-20mA are widespread in the world.
The reason is because the output in ‘current loop’ (in practice with output 4..20mA) is the most robust and reliable kind of analogical output.

In fact when precision of signal is needed, and/or distances among sensor and Datalogger are bigger than 18m, and/or there are E.M.C. disturbances, a sensor with out in current loop is an obliged choice. Of course, on the other side it’s needed a datalogger/PLC with input channel in 4..20mA. Last but not least: in most cases are enough 2 wires to supply and get data from the sensor.


Frequently the sensor is not of the same manufacturer of the datalogger and you can experience troubles or doubt in WIRING the sensor correctly with the datalogger because they are less intuitive to understand and to do. Also with SETUP of value’s range you can experience some troubles.
Then, let’s solve easily all these troubles.


Possible case of WIRING


Possible case of SETUP

When a sensor is connected to a datalogger with an input in electrical current, it is necessary to enter the calibration data. The purpose of this page is to help the operator enter the correct data required in any possible situation.

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