Input module green lights in ControlLogix are not switching on

[sban346]

have used Studio 5000 to program Logix 5571. Initially the PLC was working fine. I am in Remote Run mode. When I download the program and enable the forces on the input, the tag values are getting changed, however, in the input module, the green lights in points from 0 to 15 are not ON. However when the program runs, the output tags are written properly and the green lights indicating the 16 points in the Output module is getting switched on.

These are the module properties of the IO tree:

1756-IG16 16 Point 0V-5.5VDC TTL Input

Slot:2

Electronic Keying:Compatible Mode

Connectionata

Input Dataata

Internal State:Run Mode

Enable Change of State: All checked

I am not sure what is the issue. The OK green light indicator of the input module is ON. It is only the 0 - 15 input points not getting turned on, when I enable the forces.

Please suggest.

 

[ndzied1]

I’m not positive but I think the LEDs are hard wired to the Inputs. When you force the inputs, you are forcing values in tbt memory of the PLC.

 

[Bit_Bucket_07]

I’m not positive but I think the LEDs are hard wired to the Inputs. When you force the inputs, you are forcing values in tbt memory of the PLC.

Yes. This is perfectly normal, and applies to pretty much every PLC that I've ever worked with.