Applies To:
  • CitectSCADA 2.x 3.x 4.x

I am using Citects DDEDRV driver to communicate to an Excel spreadsheet. I have created some variable tags which address Excel cells. However, the values returned in Citect do not correspond to the values in Excel. One tag is obtaining its value from an incorrect Excel cell whilst another tag is flashing random values. 

The DDEDRV driver accesses a table of driver variable tags called VARIABLE.DBF. Records in a Dbase file marked for deletion do not get physically deleted until the database is packed. As a result, a Citect variable tag may reference the wrong address if deleted records exist in the table. The solution is to pack your database after any amendments.