DCAS Status Condition

NI-488.2

DCAS Status Condition

DCAS indicates whether the GPIB interface has detected a device clear command. DCAS is set when the GPIB interface detects that the Device Clear (DCL) command has been sent by another Controller, or when the GPIB interface as a Listener detects that the Selected Device Clear (SDC) command has been sent by another Controller.

If you use the ibwait or ibnotify function to wait for DCAS and the wait is completed, DCAS is cleared from Ibsta after the next NI-488.2 call. The same is true of reads and writes. If you call a read or write function, such as ibwrt or Send, and DCAS is set in Ibsta, the I/O operation is aborted. DCAS is cleared from Ibsta after the next NI-488.2 call.


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