X90: Analog input 4..20 mA

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1

Hi all,

I have issues using the Analog Inputs of a X90 controller, in current input mode.
I have tried in 0…20mA and 4…20mA with no success.

  • I’ve checked the external sensor and works Ok.
  • I’ve checked the input, changing to voltage input and connecting a voltage source and works Ok.

I’ve checked on channel 17 and channel 20.

I’m sure I’m missing something. Under 0…20mA or 4…20mA input mode, I expect to measure a voltage at the analog inputs pins, that should be used to supply the external sensor, but I’m measuring nothing. I’m connecting directly the analog input pin to the “+” pin of the sensor, and AGND pin to the “-” pin of the sensor (and to the GND of the controller power supply)

I’m sure I’m doing something wrong.

Thanks!!!

X90CP172_48_00 + X90AT910.04-00 + X90DI110.10-00

2

Hello Eduardo,

Welcome to the B&R Community!

Under 0…20mA or 4…20mA input mode, I expect to measure a voltage at the analog inputs pins, that should be used to supply the external sensor, but I’m measuring nothing.

The X90 analog input channels do not supply voltage to the external sensor. You can check this against the input circuit diagram and example wiring for the X90CP172 (AS Help link below).
B&R Online Help - X90 Input Circuit Diagram (br-automation.com)

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1 Like
3

Thanks!! I knew I was doing something wrong.

So, for using a self-supplied 4…20mA sensor, will this setup work?

Thanks!!

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4

Yes, that is the correct way to wire an inline power source and sensor with current output.