How to read encoder RPM

[indicator]

I need to be able to read the RPM of an encoder.  I am using a 4096 step per revolution encoder with a UMI-7764 connected to a PCI-7344.  Looking to measure speeds up to 500 RPM.  I have seen a few other places where people have asked to do this but have found other solutions.  Due to a large installed base of multiple systems (around 40), I cant change the the hardware configuration.

Specifics:

Encoder 4096 counts per revolution wired to encoder input (A,A-,B,B-)

Max speed 500 RPM

NI Motion card PCI-7344 /w UMI-7764

LV 8.5 and 10

I made a few attempts to measure number of counts in a unit of time but nothing remotely accurate or stable resulted.

Thank you

Any help is greatly appreciated.

[NateBraska]

Hi Indicator,

This will likely involve you using the Read Position.flx VI (more info about it in the Context Help or the the Online Manual). I think your idea of measuring the difference in counts versus the change in time would be the way to go. Do you have any screenshots you would be able to share on your initial implementation?

You mentioned other places where people have asked about this, what other methods did they use?

Best Regards,

Nathan B

Applications Engineer

National Instruments