CI Semi Period, Error -200141

[Duco]

I try to measure the semi-period of the signal in attach with a CI semi period counter in Labview 7.0.
I am using the example VI Meas Buffered Semi-period Continuous with a acquisition card PCI-MIO-16E-4.

I can measure the semi-period of a signal of 50KHz with a duty cycle of 25% but when I try to measure the signal in attach, signal that the frequency is lower, I obtain this message.

Error -200141 occurred at DAQmx Read (Counter 1D DBL 1Chan NSamp).vi

Possible reason(s):

Data was overwritten before it could be read by the system.

If using interrupt data transfer, try using DMA. Otherwise, divide input signal before measuring.

What can I do ??


Marc Ducommun
University of applied sciences
Switzerland

[Russell_G.]

Marc

Do you get this error when measuring the lower frequency signal? Or do you only get this error when switching from one signal to another?

How are you switching from one signal to another?

Switching from one signal to another usually causes high frequency noise which can cause this problem.

For example, if your program is running fine with a 50kHz signal, and then you flip a switch to measure a lower frequency signal, the switch could introduce high frequency which could overflow the counter.


Russell G.
Applications Engineering
National Instruments

[Duco]

Russel,

I get this error only when I try to measure the lower frequency signal, the signal in attached. But I'm not switching from one signal to another. I never changed the signal when my programm is running.

Marc Ducommun
University of applied sciences
Switzerland

[Russell_G.]

Marc

Have you tried running the �Meas Buffered Semi-Period-Finite.vi� example? If you run that, do you get the correct semi-period readings for your signal? If not, then you�re signal may be noisy which could cause the error that you are getting.

Try running a few of the other �finite� example programs to make sure that your lower frequency signal is being read correctly.

Russell G.
Applications Engineer
National Instruments

[Duco]

Russell

OK,
Thanks for your help...

Marc Ducommun
University of applied sciences
Switzerland