Applies To:
  • CitectSCADA 1.00 1.01 1.10 1.11 1.20 2.00 2.01 3.00

When the Citect CCM driver is establishing communications with the PLC it sends a request to the Scratchpad, if the PLC responds then the driver will set the Unit status to Online. Unfortunately GE seem to have a problem with the new 925 CPU to CCM module communications. In this model, requesting a read from the CCM Scratchpad causes the CCM processor to hang up. This has been verified by two other diverse methods as to be the case. If any other command (such as read a register) is made, the CCM module responds and operates correctly (provided it has not been caused to hang up by a previous read Scratchpad command). A hang up in this case means that the CCM module refuses to respond to <ENQ> from the other unit 

We are researching this problem and will post new information here as it becomes available.