01-23-2009 05:39 AM
I am trying to measure the speed of a spinning shaft using a Keyence laser tacho and a counter input on my PCI-6601.
I am unable to attach my vi but I have attached a png of the relevant code section.
- Shaft is spinning at ~6000rom
- Counter is set to Frequency measurement ona rising edge. There are 9 rising edges per revolution of the shaft.
- If I set the vi to capture a small number of samples it works fine.
- If I set the vi to measure more samples error -200141 occurs 'Data was overwritten before it could be read by the system'
- The number of samples I can obtain without a problem varies. 200 seems pretty reliable. Sometimes I can get 1200, sometimes 600, sometimes 150.
- I would like to be able to obtain ~2000 samples.
- If I try to obtain samples continuously I run up against the same problem.
If anybody can help out with this issue it would be much appreciated. It is something I keep coming up against but so far have been unable to rectify. I'm sure I'm missing something but I have no idea what.
Thank you very much,
Solved! Go to Solution.
01-23-2009 06:36 AM
Can you try the VI mentioned in this post.
Else, try placing a start task VI with 'Commit' as the input and try to stop and clear the task.
01-23-2009 08:15 AM
Thank you very much for the reply. Sorry to be a pest but would it please be possible to save the vi as a version 8.2 file or png? Our company is yet to roll out the 8.6 upgrade.
01-23-2009 08:45 AM
Moving to the large-range measurement type as suggested in the post you link seems to have solved the problem - excellent news!
Thank you very much for the help,
01-23-2009 09:42 AM
01-26-2009 03:38 AM
I'm having the same problem as described in your first post.
I am using Labview 8.0 and the supplied example for low frequency one counter.
If I try using the count edge example it counts the edges nicely.
My signal is a sine wave that goes from ~0.2 to ~4 volts.
Would you mind elaborating on your problem or solution. I'm a beginner.
My goal is to measure shaft RPM with a magnetic speed sensor. The current hardware would supply signals up to 2,000 hz, but i could vary that by making a custom steel wheel with less teeth.