1756 Analog INPUT modules

Hi,

I have a PLC rack with 5 analog Input modules where I get the max value on Inputs which are not used. the attached picture shows card #8 where the Input's 3-7 are not connected to anything but show the max engineering unit.
My guess is that the backplane or one of the modules has a power short. Any other suggestions? Help?

I don't have direct experience with this card, but it looks like the unused inputs have floated up to their max value. Try connecting a resistor to ground for each input and see if that doesn't cure the problem. 1K to 10K should work, wattage not important.

The module is just signalling a "wire-off" condition by setting the channel data to the "over-range" value.

Page 66 of the manual explains this, although confusing. The IF16 goes up-scale (+10.25 in the default configuration) for wire-off if using Float Data, and Down-Scale (-32,768) in Integer mode

Ah OK. Makes Sence. Thanks!