Applies To:
  • CitectSCADA 5.01

How come (when in Demo Mode / No Key), I can only write to one point when I am using the CTAPI or OPC? 

When Citect starts up it does the following:
  • Connect to Citect Servers that it needs (if networking is enabled)
  • Checks for a Citect Point Licence (either on the local printer port or "floating" on any of the network Citect computers)
  • If NO licence is found and Networking is Enabled - Shutdown
  • If NO licence is found and Networking is Disabled - Go into Demo Mode ...
  • If "Fixed" points are Not defined, Demo Mode is approximately 8 hours with only ONE Dynamic point allowed.
  • If "Fixed" points Are defined, Demo Mode is approximately 15 minutes with Unlimited Dynamic points allowed.
  • If Licence is found - run

The problem described is due to the fact than NO "Fixed" points are defined in the Citect Project and the Demo mode is starting with only ONE Dynamic point allowed. The reason that NO "Fixed" points were counted is because only Disk or Memory PLCs were used - Tags used in these I/O Devices are not counted by Citect at compile time. However when these tags are written to via ODBC, OPC, the API, or DDE, they are counted as "Dynamic" points, and the ONE point limit is stopping further external writes from occurring.

The solution is as follows

  1. Define an "External I/O Device" (e.g., Modicon 584 via Modbus),
  2. Create a Tag that comes from this I/O Device (e.g., Type = Digital, Address = 10001)
  3. Create a new page with a symbol based on this Tag.

Now, when Citect is compiled it will see ONE fixed point (even though the device does not even exist and is not an issue).

When Citect is run it will now start up in the Unlimited "Dynamic" point Demo mode. It will take approximately 30 seconds for Citect to decide that the "Bogus" PLC doesn't exist but then everything should work as expected.