Thanks for your comments .. this appears to be a limitation of the
Measurement VIs in LabVIEW. I don't see this limitation mentioned in
the docs or on the website so I don't see a workaround. However,
instead of using this VI, I input the signal into the counter input of
the DAQ card, which works
I think what it happening is that you are not giving the Pulse
Measurement VI enough of the cycle. It needs to have at least one
complete cycle of the waveform. If you wire the error output to an
indicator, it may be returning an error that is something like this:
-20308
ma_ptmFetch.vi when
Yes, that is the error that is occuring .. I do not know how to get
longer sample .. how do I get the measurement VI to wait and gather
more samples?... it seems to be timing out if it doesn't get a
complete cycle in a certain length of time .. so I can't measure slow
waveforms.
dave
I see your problem. You are getting data in through something like a
DAQ or VISA call and you just aren't getting enough points to make the
measurements with this VI. You can either collect several of these
together and then make the pulse measurement, you can tell the input
to take longer
You have not mentioned the hardware that you are using to generate and
measure pulse. If the hardware you are using is FP-CTR-500/502, I
have a suggestion. The terminal count value that is being used has a
direct effect on the value of the frequency generated. If the value
is set in the range
actually the hardware is unimportant, I am currently testing and using
a square wave function generator (0-5v signal) .. although I use the
built-in waveform synthesis to generate either square or sine waves
and get the same problem.. The problem seems tied to all the timing
measurement VI's ..
In using the Pulse Measurement (built-in) VI more I see it cannot
measure pulse periods when the frequency is below about 15 hz .. at
least on my system. I am simply bringing in a simulated sine waveform
and leaving all the defaults on the pulse measurement VI.. is there a
way to extend the range
