Digital input to rpm

[Hooovahh]

Well if you aren't getting the right data then there is no hope to getting your correct rpm.  I'd open a test panel performing a continuous, or finite read just to get some high speed data and see that it does change not just all 0 or all 1.  If that doesn't work I'd assume there is a problem with your setup.  You'll likely want to check it with a scope, and check your pin out.

[ashnu]

I have connected the digital out from picoturn to P0.0 and D.GND of BNC 2110. In DAQ assistant I selected Line input --> port0/line0. Then I selected N-Samples with 1000 number of samples and 10kHz sample rate. The external source is PXI_CLK10 with timeout=1s. I followed the BNC and PXI-6251 manual for all these. I would like to know if there is any correction needed in this settings. 

And in test panel for digital input, when I run it just one LED turns on and off when the turbine is running. 

I connected this picoturn to voltmeter and saw that the frequency increases as I run the turbine. Therefore, the device is working fine, the connection is proper but still why am I not getting a combination of 0s and 1s in a set of specified sample (at the DAQ assistant output)? 

I am getting an array of [0 0 0 0 0 ...0] of 1000X1 and then [1 1 1 1 1......1] of 1000X1.

Thanks

Ashnu

[JÞB]

1000 samples at 10kHz = 0.1 seconds

A picoturn outputs a %50 duty cycle TTL singnal that changes state each time something passes in front of it.

You will need to set your sample size and rate depending on what frequency you are expecting to measure.  What frequency are you seeing?

[JÞB]

Oddly, There is a serial port on that device and a LV Wrapper for the Driver DLL.  A little RS-232 would give you the exact answer

[ashnu]

Hey Jeff·Þ·Bohrer,

I am expecting a frequency of 40Hz at low rpm (say 500). Thanks you soo much for the idea of RS-232, you really made a very through inspection of the problem. Your input helped me a lot. The problem got solved. Thanks a lot 🙂

Thanks to everyone for all your inputs and interest 🙂