Applies To:
  • CitectSCADA 1.00 1.01 1.10 1.11 1.20 2.00 2.01
Summary:
If Citect is communicating to one port of the Hitachi PLC and The PLC programming software is communicating to another port then if you try to do a "save to PLC" it will fail.  

Solution:
When Citect is communicating with the PLC it takes a read token (or read occupation) from the CPU. When the programming software is requested to do a "save to PLC" it also needs this token but it will fail because Citect already has this token. the solution is to do a "Force free occupation" under "communication" in the programming software, then do the "Save to PLC". This will put Citect off line after about 30 seconds and then it will re-initialise and go back on line again. This is limitation of the Hitachi PLC. 
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