Add a Modbus Slave on AC450 with CI534V02?
I have an Advant system with CI534V02 Modbus MVI boards installed in AC450. In this case the AC450 is configured as master on the Modbus.
Is it not possible to add a new Modbus slave node without restarting the controller? There does not seem to be any note about this in the manuals. I can create a new node (MVINODE) without any system messages being posted, but it seems that the controller does not recognize this new slave and makes no attempt to communicate with it (I am expecting the CI534 to at least send a function code 08 poll to this slave).
The Modbus is working fine with the existing slaves on each port, only the added slaves are not working. Cycling :IMPL and/or :SERVICE on the MVI object does not bring these slaves to life.
Am I trying to do something that cannot be done? Is there any documentation about this limitation? Any tips would be much appreciated. Doing a cold start on my controller is really not an option.
Well, the documentation says you only need to cold start the controller if you change the Network and/or node number of the MVI, (ie the AC450 Master) so you should be able to add another modbus slave Without restarting. Its much more likely that you have made some other error in your configuration.
The AC450 probably wont send a poll command until you have all of the MS elements set up properly. Make sure you have worked through EVERYTHING in the manual, then go home, have a beer/wine/tea/coffee etc, get some sleep and come back tomorow and check it all AGAIN - which is when I usually find a couple of errors. Remember you need to make some adjustments to the existing database for the PLC status words as well as build all the send and receive commands for the new RTU. Check also if you are using a PC program to control the link as you will need to patch that as well.