RPM measure

[pollon]

Hi i have to measure the RPM of a DC fan using a optical sensor that generates a 0-5V... Can anybody give me a hand? I use a NI 9401

Thanks Pollon

[Wayne.C]

Are you using this module on a cDAQ chassis or a CRIO?

[pollon]

On a cdaq

[pollon]

Hi i'm trying to read with signal express a 5V ttl signal generated by a function generator, but what i see on the screen is very disturbed signal. Could you please tell me why?

[AndreaN]

Hello Pollon,

since you're using a Compact DAQ chassis, you can put the NI 9401 module in either slot 5 or 6 of the chassis 9172 to use one of the two counters.

You can do then a simple counter frequency measurement to get the frequency of the TTL signal.

Take a look at this link to learn more about frequency measurements with cDAQ:

Frequency Measurements: How-To Guide

Hope this can help.

Regards,

Andrea N.