Why is Automatic Serial Polling Unexpectedly Enabled in NI-VISA? Primary Software: Driver Software>>NI-VISAPrimary Software Version: 4.2 Primary Software Fixed Version: 4.2 Secondary Software: Driver Software>>NI-488.2
Problem: I usually operate with automatic serial polling disabled. However, after I run a program that uses NI-VISA, I notice that automatic serial polling is now enabled. My program never made any calls to enable automatic serial polling. Why is this happening?  Solution: NI-VISA enables automatic serial polling when enabling service request events for GPIB Instruments. Disabling service request events does not disable the automatic serial polling because there may be other instruments with the service request event. Disabling automatic serial polling would stop all other open NI-VISA handles from catching the service request events. One workaround is to make a NI-488.2 call to disable automatic serial polling on a board level handle just before your application exits. An example of how to do this is below. // Open a handle to the board board = ibfind (GPIB0); // Disable Automatic Serial Polling ibconfig ( board, ibcAUTOPOLL, 0 ); // Close the handle to the board. ibonl (board, 0); Related Links: Attachments:
Report Date: 12/17/2007 Last Updated: 12/18/2007 Document ID: 4GGHBCQA |
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