Output Forces in ControlLogix

I have a ControlLogix processor, V13 firmware.

I am able to force the inputs with no problem. The outputs will not force, either from the ladder or the data table.

Anybody seen this before??

thanks,

alan

You have to realize how forcing works in Allen-Bradley PLCs. When you force the output, you affect the "physical" output only. So if you force an output wired to a light, the light will energize. This has NO effect on your ladder logic. You will not "see" any change in the logic window.

Other than that, there is no difference in forcing inputs versus outputs.

Keep in mind also, that you can only force real outputs or aliases to real outputs. If it is internal, it won't work.

Also... make sure that you are looking at the output tag. For example:

Local:2:I.Data.5
Local:2:O.Data.5

Both examples are valid addresses for an output module in slot #2 of the local chassis. The first is simply reading what the output was told to do, whereas the second is telling the output what to do.

OG