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A bit about my redundancy setup - the PLCs I’m communicating to have redundant modbus communication cards. Each comms card has its own IP address, but in the back end the 2 cards are reading and writing to the same PLC memory points.

Some other SCADA systems I’ve used have support for this built in - when setting up the comms driver, you can tick the box for redundancy, and add the second IP address. The SCADA system then gracefully fails over between the primary and secondary channels based on channel health. At a tag level, this is transparent.

Given this isn’t supported out of the box in Ignition, I’m trying to manually create it. I have simply setup 2 modbus drivers, and then at a UDT level I’m parametrising which driver to use. Lastly, I’m having a gateway script monitor the health of the modbus drivers and adjust the UDTs to change between the 2 drivers as required. This should affect hundreds of tags at once.