Using NI cDAQ for Monarch Optical sensor

[JR3]

Hi,

We recently purchased a cDAQ 9172.  We are planning to use a Monarch remote optical sensor for it to measure RPM. We already have the NI 9205 for other application.  Can I use NI 9205 to measure it or do I need to buy a different module like the NI 9401? I'm just a beginner in using Labview so I don't know if this is possible.

The specs for the Monarch optical sensor;

http://www.monarchinstrument.com/pdfs/manuals/1071-4854-115%20ROS%20Eng.pdf

Thanks a lot

[AdnanZ]

You could use the analog input module to figure out the frequency but you will need to do a FFT analysis on the signal coming in. Or, you can use a digital module to do counter measurement to figure out the frequency of the signal, which can then be converted to RPM. Since you're using a cDAQ chassis, you can put the digital input module in either slot 5 or 6 of the chassis to use one of the two counters provided in there. 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

[JR3]

Thanks Adnan Z,

We are only using one optical sensor for RPM so we are contemplating on buying another module for it. For the FFT analysis, would it will be still accurate? I'm just using DAQ Assistant to get the analog voltage.  Do the site have some tutorials for it cause I'm kind of lost on how to do this?

Thanks

[AdnanZ]

It will be accurate. That is the algorithm to use when you want to figure out the freuquency of an analog signal. You should do a quick search for FFT on NIs website and in the Example Finder.