Applies To:
  • CitectSCADA x.x
Summary:
The Citect runtime seems to be displaying the wrong variable tags or no value at all sometimes. Or, a 3rd-party OPC client is failing to read certain variables from Citect's OPC server. 

Solution:
Some drivers access a table of 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. Also, if variables are defined in an include project, they won't be listed in the main project's VARIABLE.DBF. As a result, those variables can't be accessed by this type of driver.

The following drivers require the database to be packed and the variables to be defined in the main project:

DDEDRV The DDE driver

 

OPTOMIST The Opto22 Mistic driver

SIXNET The SIXNET driver to SIXNET's Control Room for Windows software

STEEPLE The driver to the Steeplechase SoftPLC

The following drivers require the database to be packed:

DDEDRV    The DDE driver
OPC             The OPC client driver
OPTOMIST The Opto22 Mistic driver
SIXNET       The SIXNET driver to SIXNET's Control Room for Windows software
STEEPLE   The driver to the Steeplechase SoftPLC

See also knowledge base articles Q1997 and Q4075.

 
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