Applies To:
  • CitectSCADA 1.00 1.01 1.10 1.11 1.20 2.00 2.01
Summary:
Under some conditions you may find that a client Citect cannot communication to a server. If you restart the server the client will be able to communicate to the server. It his caused when the server can no longer create any new sessions for new clients. You will find that the server will continue to communicate to other clients, however if you restart those clients they will also not be able to communicate to the server.

Under these conditions the Clients will display the hardware error 'No server could be found'.

 

Solution:
This can be caused by several problems:

1). There is a known bug in the Windows for Workgroups 3.11 driver for the 3 Com Etherlink III network card when used with Novell ODI drivers. See Q1046 for details. A later driver is available from Microsoft to fix this problem.

2). Old drivers can cause this problem especially when Windows for Workgroups 3.11 is used in conjunction with Novell Netware. Make sure you always have the latest drivers from Novell and Microsoft for your particular network interface card.

3). This may occur if the server runs out of NetBIOS control Blocks. If the sever is running out of NCB's you will get the hardware error 'Out of buffers' on the server (this error message was include in version 2.10 and later) and the task 'netb.start.rec' will start running in the Citect Kernel (see Page Tasks). If you are using a real mode protocol driver then increase the available NetBIOS Control Blocks. Most protected mode protocol drivers don't allow you to change the number of NCB's as they are allocated directly from available memory. If you are using a protected mode driver make sure you have enough free physical memory.

 
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