How do I know if I have a series A, B, or C for my micrologix 1200 part number 1762-L40BXB. When I go to create a new project with RSLogix 500 it gives me 3 choices.

There's a sticker on the right side of the controller that lists the Catalog Number, Series Letter, and Revision Letter.

The MicroLogix 1200 I have on my desk, for example, reads 1762-L24BWA Series A Rev B.

I know I've had programs fail to run when I don't get the Series letter correct for a MicroLogix 1500, which uses a modular base unit. But I don't recall this being important on a MicroLogix 1200.

Thanks, I was hoping I could tell before the unit came so I can start my program (which by the way I will need help on!) Is it possible to change the series later if you select the wrong one?

Series C introduced floating point memory.

If you select the wrong processor in your project you can always change it. For safety you might want to select an A, then you will not have any non-compatible code.

Try to connect to the processor regardless of whether you have a program stored in it or not. Since you don't have a copy of a program, you will be able to select "Online now". This is going to give you a couple errors, followed by a blank program. The program is configured to exactly the right specs for the processor you have.

This method works with PLC-5, SLC, and all ______Logix families. It probably works with PLC-1,2,3, but I've never actually worked with any of them.

If you are purchasing a new one then it should be a series C, they have been out for a long time

Thank you