Applies To:
  • CitectSCADA 5.xx, 6.00

Can I have tags defined in my CitectSCADA project that do not exist in my ABCLX device?

When I have defined tags in SCADA, other tags which are defined in SCADA and the PLC stop working.


No. Tags that are defined in CitectSCADA that do not exist in the PLC are considered to be bad tags. If your project has one bad tag, the optimised block that the bad tag exists in will cause all of the other tags in that optimised block to be treated as bad. Each optimised block contains up to 256 bytes of data, so if your optimised block was filled with REALs (i.e. tags of data type REAL) you would have up to 64 tags in the optimised block. If one of those was a bad tag, it would cause 64 of your tags to be considered bad (i.e. you will either have #COM or 0 displayed depending on your choice of ini parameter on how you wish to have your bad data displayed). The same example but with an optimised block filled with DIGITALs would mean that one bad tag could cause up to (256 x 8) 2048 tags to be considered bad.

Please note that optimised blocks are likely to contain multiple data types. The examples given in this KB have been simplified in order to convey the importance that all bad tags in your project should be eliminated.

Refer to Q3994 and Q4253 for help logging bad tags in the ABCLX driver.