Change Logix5000 Module IP in Run mode/ Dynamically

Hi,

I wonder if someone has done this already?

We are trying to change the IP address of a Generic Ethernet-Module dynamically using code in Run mode. We have two different data sources and the remote system (Gods Knows what it is) will tell us where to get data from by sending us the Source IP address. The Logix PLC (1756-L71) will set the new IP address for the generic Ethernet-Module and start receiving same data from different physical source.

The idea is Duty/Standby system...if one system is down the PLC will then receive data from standby system. The other option may be to configure Generic Ethernet Module for both data sources and use which ever is valid.

BUT

This will leave one module in connection fault all the time and will require extra work around to display correct status on SCADA for correct module and keep the name of module same etc.

I've done things like this with robot end-effectors and exchangeable tooling.

As far as I know, you can't programmatically change the IP address of an I/O object in the I/O tree of ControlLogix.

For a system like the one you describe where there are only a few options, the straightforward solution is to put all the possible objects into the I/O tree.

You can either simply ignore the faulted I/O connections from the ones that aren't connected, or you can use SSV instructions to programmatically Inhibit or un-Inhibit them.

Thanks Ken,

I was thinking the same i.e. to inhibit the module not required. I was just looking for neater solution.

What if the remote system uses DHCP so the IP address is not fixed? which is not my problem but just curious.

Could you help me find the Instance, Class, attribute etc for CIP Messages for Generic Ethernet Module? such as to read the IP configured for the modules in the IO tree?

I mean is there any document where I can find this?

I would recommend you to inhibit module that is not in use.
When you have a faulted connection, controller constantly trying to reestablish it, using an unconnected buffers.
There is a limit on these. More I/O you have faulted, more buffers will be used.
The same buffers used to send messages so you may see MSG instructions faulted time to time. There are other reasons not to load unconnected buffers.

Could you help me find the Instance, Class, attribute etc for CIP Messages for Generic Ethernet Module? such as to read the IP configured for the modules in the IO tree?
I mean is there any document where I can find this?

Click to expand...

Starting with V24, you can read configured project Module path using GSV instruction.
From there you can extract IP address.

Reading the actual IP address from a remote module is possible but this is catch 22, because you need to specify IP address in the MSG instruction.
You probably need to configure DHCP persistence or static addresses instead.