Tach formula

[jstalman 0]

Hey guys, I have a project where I have a prox counting the teeth of a 64 tooth gear to determine speed. What would be the most accurate way to calculate the rpm? I am using a contrologix l36-erm processor and have a 1769-HSC card installed. My prox is rated for 2khz switching speed. Thanks for any help in advance.

[rex5192 0]

[rex5192 0]

[JRoss 84]

That card has built-in rate calculation that you can use as a base for figuring RPM. Check out the section in the manual titled "Cyclic Rate Calculation Method". It's page 32 in the one I have from a couple of years ago. You can use that to get number of pulses per second, then go from there.

[jstalman 0]

Thanks I'll have to look up the manual.