Hi,I'm trying to set up change detection for an 8 bits digital input port. When I configure all the port lines (one channel per line) and activate an input of the port, I get the following result:- The DAQmxReadDigitalLines call wakes and the right line is detected (set to 1);- The DAQmxReadDigitalLines call wakes a second time and I get an array of zeros;- The DAQmxReadDigitalLines call wakes twice again and I get the same results than the two first calls;This happens every time I activate an input but the result does not come necessarily in the same order.All the lines of the port are configured for raising and falling event.Any idea of what the problem could be ?

Digital I/O

Change detection using PCI-6514 and Ni-DAQmx

Hello Daniel,

finally I've succeeded in using filter on the input of 2 ports and with signal event:

DAQmxCreateTask("TaskSurveillance",&taskHandleSurveillance);
DAQmxCreateDIChan(taskHandleSurveillance,"Dev1/port1/line0:7, Dev1/port2/line0:7","SurvPort",DAQmx_Val_ChanPerLine);
DAQmxCfgChangeDetectionTiming(taskHandleSurveillance,"Dev1/port1/line0:7, Dev1/port2/line0:7","Dev1/port1/line0:7, Dev1/port2/line0:7",DAQmx_Val_FiniteSamps,1);
DAQmxRegisterSignalEvent(taskHandleSurveillance,DAQmx_Val_ChangeDetectionEvent,0 ,DeviceChangeDetectionCallback,NULL);
DAQmxSetDIDigFltrEnable(taskHandleSurveillance, "Dev1/port1/line0:7, Dev1/port2/line0:7", 0);
DAQmxSetDIDigFltrMinPulseWidth(taskHandleSurveillance, "Dev1/port1/line0:7, Dev1/port2/line0:7", 0.01);
DAQmxSetDIDigFltrEnable(taskHandleSurveillance, "Dev1/port1/line0:7, Dev1/port2/line0:7", 1);

Pulse width of 0.01 sec is fine to avoid noise on input.

Best regards,

PEY

Message Edité par pey le 09-18-2006 04:23 AM

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Digital I/O

Change detection using PCI-6514 and Ni-DAQmx

Re: Change detection using PCI-6514 and Ni-DAQmx