Hi,
I'm a noob after some help if possible.
I have been using a Click PLC with a 0-20mA analog input module, quite happily, for some time now. I have been using 2 and 3 wire transmitters with no issue. The problem I am now experiencing is with a 4 wire transmitter that is powered from a supply separate to the PLC. I measure a steady 4mA, in the transmitter loop output, with a multi-meter but when I connect the loop output to the PLC (between channel input and 0V) the PLC reads over-scale i.e. status monitor shows maxed out at 20mA.
This has me confused - does anyone have any advice they can offer?
Is this anything to do with input impedance and could I need an additional resistor?
I would be greatly appreciative of any assistance.
Cheers,
I'm a noob after some help if possible.
I have been using a Click PLC with a 0-20mA analog input module, quite happily, for some time now. I have been using 2 and 3 wire transmitters with no issue. The problem I am now experiencing is with a 4 wire transmitter that is powered from a supply separate to the PLC. I measure a steady 4mA, in the transmitter loop output, with a multi-meter but when I connect the loop output to the PLC (between channel input and 0V) the PLC reads over-scale i.e. status monitor shows maxed out at 20mA.
This has me confused - does anyone have any advice they can offer?
Is this anything to do with input impedance and could I need an additional resistor?
I would be greatly appreciative of any assistance.
Cheers,