PLC, Drive and HMI talking

[sirius0 1]

In the past I am sure I have changed the IP addresess on both HMI and PLC and they have continued to work and talk to one another. But I don't get how this really works or how it is set up. For instance if the HMI sends a message to the PLC how does it know which one?Where in the PLC and HMI are these settings? I can find the IP settings for the device in the ethernet card but not the IP the device would want to talk to. Also I need to know how to do this with a VSD. I have machines that have been relocated and neeed new IPs to conform with the local IT so I have to change them all at once. Thank you.

[Mark- 17]

Hello, It would really help if you supplied the name of the HMI.

[sirius0 1]

Panel View Plus 700 compactlogix L32E powerflex 40 DSI with 22-comm-e DSI to ethernet interface.

[NatiJacket 0]

There are two seperate parts here, how you change the IP addresses of the devices (which you seem to have figured out) and how to configure the device to communicate by pointing them to the right IPs. There are a couple ways to do the latter depending on device: 1. If you are using FactoryTalk View ME or SE, communications are configured in the program. If you change the IP address of the controller you would have to go into the FTView and point the HMI back towards the controller. 2. The IP address could also be configured in RSLogix 5000, either in a MSG instruction directly or through the communication tree (I think this is true for the HMI, not 100% sure) When you add a drive to the communcation tree in RSLogix 5000 you can set the IP address of the drive there. Edited 11 May 2012 by NatiJacket

[sirius0 1]

Thank you, very useful comments and clues.

[sirius0 1]

Well I have been migrating PLC, VSD, and HMI to new IPs and getting them to talk to oneanother a few times now. QED!! Thank you all for your help.