PLC -5/30 IP Address Change

[rajj03]

Morning All,

So I have a PLC-5/30 with a 1785-ENET module that I am needing to change the IP address on. I know very little about PLC's but have been tasked with this as no else here at my job has any experience. I looked up how to change it and seems there are a few more steps than just changing it in RSLinx. I want to avoid doing something incorrectly and shutting this thing down so would someone mind jotting down some instructions on how to do this? Thanks!

 

[mylespetro]

I've never specifically done it to a PLC-5, but typically you would need to change it in the PLC program and then download it to the processor. You should be positive that there are no other PLCs or HMIs communicating with the controller using the original IP address before doing so.

 

[Operaghost]

It's been ages, but I don't think you can change it online. Open the file Offline in RSLogix 5 and on the tree on the left side of the screen double-click the Channel Configuration. Click on the tab for Channel 3A. From there you can set the IP address.

Once done you will have to shut down (switch to PROGRAM mode) the PLC in order to download the changes to the controller. Make sure it is safe before shutting down.

If you are communicating to the PLC using the ethernet connection, then during the download the address will change, and you will get disconnected. That is OK. You must go into RSLinx and reconfigure the Ethernet driver. Modify the IP address setting in RSLinx. Keep in mind that here in RSLinx you are simply telling your computer what address you expect the PLC to be using. RSLinx settings do not change the controller's address. It's like setting up a new contact on your phone. You enter in what you believe is the correct phone number for the other person, but what you are doing doesn't change the number on their phone.

OG

 

[Ken Roach]

Some context: in PLC-5E, SLC-5/05, and MicroLogix 1100/1400 controllers, the IP address is part of the user application program. That's why you have to change it in RSLogix. The controller's operating system determines whether or not it can be done online.

In all ControlLogix family controllers the IP address is stored in nonvolatile memory in the Ethernet module itself. In some controllers the Ethernet module is physically separate, and in some it's just logically/virtually separate.

If you were familiar with ControlLogix, you might expect to right-click on the 1785-ENET module and enter an IP address, because it's physically a "sidecar" module to the PLC-5/30 controller. But because it's the old PLC-5 architecture and operating system, that module functions as "Channel 3A" and gets all of its configuration from the PLC-5 program.