Another solution is to create 2 opc tags and a reference tag for each data you read in the plc. You monitor the primary and standby cpu and you write a parameter in each udt that drive the reference tag, for example the parameter is the folder in the path of the opc tag.
This solution is quite robust with a quick failover and all the data switch together.
Creatings tag take more times but when you have have some scripts to generate them that is not a problem.
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