PLC5 Input Module

Hi there,

Could someone explain how does de Input and Output Modules works.
I am using a 1771 IAD 120 AC/DC Input Module with a PLC5 Allen Bradley.

I am new with this. Does the Input Module has to be grounded or it is already grounded with the Backplane or trough de PLC? The last terminal of the Module is called "L2 Low return" I dont know what this means.

I wired a simple button with 120 VAC. One wire to the 120VAC supply and the other wire to the Input Module but I think the ground wire is missing, Is it?

You need to wire it up to your Neutral/Common (not the same thing as your ground).

Page 7 of this:

http://literature.rockwellautomation.com/idc/groups/literature/documents/in/1771-in023_-en-p.pdf

will show you how to wire it up.

If you don't know what "L2" means I would recommend you get some help. 120VAC will kill you.

Having said that, as rootboy said connect "L2" (terminal E) to the neutral side of your AC power source.
It may or maynot be grounded.