How to get analog Tacho signal in PCI 6250 NI card

[Suraaa]

Dear All,

Iam using Labview 8.6.1 and NI PCI 6250 card. In my application i need to get order power spectrum for particular speed and accelerometer signal. For that iam using labview example program Order power spectrum(Analog Tacho).VI. In my PCI6250 card i configured AI0 as Accelerometer signal and AI 1 as speed signal for analog tacho signal. In that example program i can get Amplitude of Acclerometer signal But i cant able to get Speed Profile. For Speed iam using encoder, from that encoder Digital pulse i connected to analog channel 1. Whether this connection is correct? Instead of giving digital pulse directly i tried analog signal based on 0-10v for 0-1500rpm. This configuration also is not working. Encoder PPR is 1000. Can any one help me to solve my problem.

Regards,

Vijay.

[preston_johnson · Accepted solution]

At 1800 RPM you are rotating at 30Hz.  for your encoder pulses are coming at 30,000 Hz.  You need to sample the analog encoder channel at 100,000 Samples per second or more.  Graph your analog inputs on a time waveform graph to see if you are getting a clean signal. 

With the analog tacho vi, you need to provide the number of pulses per revolution, so it can determine the correct speed. 

[Suraaa]

Thanks for your reply....

Now it is working....

Regards,

Vijay