What ground connections are required when wiring a voltage input?
AS/ AS-P Power Supply
Universal Input Modules.
0-10V, 0-5V sensors
The required connections are different for isolated and non isolated voltage inputs.
Consideration of the system grounding is also required.
If your input sensor is isolated it can be directly connected to the UI and RET terminals of the Universal Input module.
An isolated sensor will have 4 terminals (2 power terminals G0 and G, 2 output terminals M and X) the power ground G0 is not directly connected to the output ground M terminal.
However for non isolated sensors (usually 3 terminal devices) the signal terminal X will be wired to the UI input, but the sensors signal common G0 should be wired directly to the Signal Ground for the installation, not to the RET terminal of the IO Module.
On every Input modules ensure that one RET terminal from the IO Module is wired directly to the Signal Ground.
Full details of the required wiring and an example wiring drawing showing isolated and non-isolated voltage inputs can be found in "Wiring" section of the Hardware Reference Guide available on the Download Center.