03-05-2008 06:03 PM
03-05-2008 08:13 PM
03-05-2008 08:27 PM
Hi Nick,
I found that Timing and Transition block in Signal Express after I posted the message. It seems to work if I decrease the continuous sampling rate to around 500Hz and have a buffer(samples to read) that is twice that, so around 1k or more in the DAQ Assistant block. if I don't do that, it will give an error, is that because the buffer must have at least one full period?
Previously I had been trying to use a Pulse Measurement block. I think that it must timeout after a certain time period or number of readings if it hasn't detected an edge and since my signal has a high period it kept giving an error.
Thanks for the help and quick reply!
Bill
03-06-2008 01:44 AM
03-06-2008 03:57 PM
It says:
Error -20308 occurred at (waveform index 0 of 1)
Possible reason(s):
Analysis: The waveform did not cross the mid reference level enough times to perform this measurement. Check the signal length, reference levels, and ref level units.
03-07-2008 01:12 AM
08-13-2008 12:10 AM - edited 08-13-2008 12:11 AM
08-13-2008 05:15 PM - edited 08-13-2008 05:15 PM
Hi Suneel,
Here is the block diagram along with the VI.
Regards,
Kent
Applications Engineer
07-06-2009 01:16 PM
Hi,
I am having a similar issue with PW Measurement, I need to read a Duty cycle in a percentage range from 0% to 100%. The problem I have is the same: that it has not crossed the reference enough times to measure, or the histogram cannot be used. This is obvious, yes, because there is no pulse, it is essentially all true or all false, but the pulse Measurement vi cannot handle this. Is there another way I could measure duty cycle, so that I can see if there is a low (0%) or High (100%), and everything in-between?
Thanks,
-Corbin
07-07-2009 10:07 AM
Corbin,
It is not possible to measure zero frequency. You would need to wait an infinite time. Before you finished you would need to update to LV12. Then your measurement would start over.
You must define the longest time you are willing to wait for a result and declare that any signal which has not had the necessary transitions within that time to be functionally equivalent to zero frequency.
Once you have determined the acceptable limits, then you can look at how to implement this with your hardware.
Lynn