Applies To:
  • CitectSCADA 1.00 1.01 1.10 1.11 1.20 2.00 2.01

Citect for DOS client support from Citect for Windows has the following problem with DECNET 4.1 and Windows for Workgroups 3.11. The Citect for Windows computer will stop transmitting datagrams with an "out of ncb" error (0x22). This may also cause the computer to crash back to the C: prompt or GPF. When Citect for Windows is shutdown, the computer will either crash to C prompt, freeze, or produce an EMM trap. 

A solution to this problem is to put the following option in the CITECT.INI file:


This limits the number of receives buffers to 1 and seems to solve the problem.

This problem was found on a DECNET (4.1) network wth WFW 3.11 and a load of around 150 packets per second. It is unknown if this problem only occurs under these conditions.

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