9401 timeout when using c api

[ft1337]

Hello everybody,

I want to measure a frequency using the c api.

So I took the C example "DigFreq-LowFreq1Ctr.c" and ran it.

The interesing lines are:

DAQmxErrChk (DAQmxCreateTask("",&taskHandle));
DAQmxErrChk (DAQmxCreateCIFreqChan(taskHandle,"Dev1/ctr0","",1.192093,10000000.000000,DAQmx_Val_Hz,DAQmx_Val_Rising,DAQmx_Val_LowFreq1Ctr,0.001,4,""));

DAQmxErrChk (DAQmxStartTask(taskHandle));

DAQmxErrChk (DAQmxReadCounterScalarF64(taskHandle,10.0,&data[0],0));

I always get a timeout when trying to acquire the frequency value:

-200474. Specified operation did not complete, because the specified timeout expired.

I'm using a NI 9401 on slot 4 of a cDAQ-9174 (4 slot USB compact DAQ).

The example to count edges works fine for me so I'm wondering what I'm doing wrong.

Do I have to route a clock source to the counter first or did I forget something else here?

Thank you in advance.

King regards,

Fred

[Christian-P]

Hi Fred,

please have a look at this Knowledge Base:

http://digital.ni.com/public.nsf/allkb/4E017925BDF2DC2D862572E6007C9594

Any input frequency below 100Hz yields error -200474, so you have to delete this error programmatically.

The introduced approach in LabVIEW can also be implemented in C.

Best regards

Christian