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Error -200141 with Low Frequency Counter Measurements

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Hello there,


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.


The problem:

- 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,




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Message 1 of 6

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.


"A VI inside a Class is worth hundreds in the bush"
യവന്‍ പുലിയാണു കേട്ടാ!!!
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Message 2 of 6

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.


Thanks again,




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Message 3 of 6

Hi again,


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,




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Message 4 of 6
Accepted by topic author MartinMcD
8.2 version

"A VI inside a Class is worth hundreds in the bush"
യവന്‍ പുലിയാണു കേട്ടാ!!!
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Message 5 of 6

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.



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Message 6 of 6