Applies To:
  • CitectSCADA 3.x 4.x

The TITCPIP Protocol driver does not support addressing LONG or REAL data types on inconsistent address boundaries. For example a Project should not contain variable tags for a LONG at V1 and a LONG at V5. Even though the data in these tags does not overlap the protocol may generate occasional errors when attempting to reconcile the conflicting address boundaries in a blocked request.

In this case the driver error reported will be 0000012.

An example of the error shown in the syslog.dat is:

READ 0008 P1 IO1 V1925 30
Generic 000008 Driver 00000012 (0x0000000c)


CIT has confirmed this to be a problem in Citect for Windows version 3.XX and 4.XX. We are researching this problem and will post new information here as it becomes available.

New projects should avoid using tags of the LONG and REAL data type on a conflicting address boundary. Normally this condition is flagged as an error by the Citect compiler. Existing projects may use the protocol parameter MaxPending = 1 as a workaround to prevent the error.

For example in the Citect INI file.