Applies To:
  • CitectSCADA 5.xx

When a Citect Memory or a Disk PLC is used with tags with very high addresses for some protocols, the tags do not work at runtime.  For example the Memory PLC and disk PLC will not correctly read or write to Modbus address 465000 at runtime. 

The problem occurs at runtime with tags that are compiled to large address values. The Memory PLC and Disk device have been enhanced to work with large addresses.  This disk driver will write out its file in a new format which will not be compatible with the old Disk driver format. The new driver will however be able to read the old driver format.

CIT has confirmed this to be a problem in Citect for Windows versions 3.xx, 4.xx and 5.xx.  This problem has been fixed in version 5.30 Service Pack A.