Applies To:
  • CitectSCADA 2.x

We have encountered a problem with a Citect v2 workstation communicating on a network. After the machines have been running for about 20 minutes, without being touched, the v2 machine displays a dialog box with the message "File (ct_tran.c) Line (1913) Error Tran Buf Overflow". The machine must be restarted for it to work correctly again. 

This problem stems from Microsoft's implementation of NetBIOS. This only occurs with Windows for Workgroups and Windows 95. This problem does not exist with Windows NT. It has to do with using multiple receive NCBs when reading network information. Citect uses a default of 2 NCBs to read the NetBIOS information from the network. Sometimes when the Client is receiving a lot of network information these NCBs can be passed back to Citect in the wrong order. Citect picks this up and thus generates the above error. However at this stage Citect's networking is unstable and thus Citect may actually crash. The simple work around for this problem is to use only one NCB for receiving information. This is done by setting the following parameter in the Citect.ini file.


There may be a performance degrade but this has been measured to be nominally 5%, never more than 20% and sometimes no degrading effect at all.

See also Q2044.