800XA 6.0 and 5.0 System parallel operation
Is it possible to have AC800M OPC talking to 800XA 5.0 SP2 and 800xa 6.0.3 system parallel during a upgrade process.
New 800xa 6.0 system
BU level Lib is modified ( LIBRARY Blocks are changed, new variable and module name)
New Domain 800xa 6.0
New Service account in 800xa 6.0
I'm no authority on the matter (like Hans N here on AKS) but as far as MMS I can tell you that I have MMSReadCyclic reading Access Variables going 24/7 between some 15 different AC 800M controllers on version 2.0 up to 6.0.3 (through most versions in between). No issues seen so far.
In case the MMS blocks are encapsulated in some library, etc., ask the author of the library.
Short answer ... NO !
Long answer .... If you connect one OPC server control panel from each version of the system to each AC800M, then yes you can read/write data from either system. BUT the OPC servers will not be syncronised. They will probably not be the same and you're on your own if you try and download changed code to the controller. This is completely unsupported and things could very easily break catastrophically. Don't do it!!!
The upgrade path that actually works ...
Use Soft Controllers in the newer version of the 800xA system to perform the upgrade. Mark the controllers as "Simulated" and copy the ColdRetain and Retain data files from the version 5 system to the version 6 system before you actually upgrade the AC800M code. Follow the upgrade procedures CAREFULLY - especially the parts about cold retain file handling.
When you first load the upgraded code into the SoftControllers, the cold retain values from the original version 5 system will be loaded into the softcontroller ( assuming that the variable names and paths are the same).
When you then go offline from the softcontrollers you'll get updated coldretain files in the Engineering Station. These cold retain files can then be loaded into the real version 6 system when you upgrade.