BS2 RPM Reading

ZouLou

Hi everyone, I am new here and pretty new to the basic stamp. I am working on a school project. I am wanted to measure the shaft rpm on a small scale wind turbine. I have a incremental capacitive encoder (CUI AMT103). I have been searching the internet and the forum but have found little information that I found helpful on this specific topic. I apologize if this question has been pounded to death before. I am a regular on a few forums and that can get annoying. Thank you very much for helping a new guy. Any information or help is extremely appreciated.

-Kyle

stamptrol

HI Kyle,

You can probably use either the COUNT or PULSIN instruction to check how fast the encoder is spinning. See the Helpfile in the programming software.

You'll want to select a relatively low pulse per revolution number, depending on the shaft speed you're measuring.

Cheers,

ZouLou

Thank you very much for the reply. The max RPM is going to about 600 RPM. What is a safe sample speed per minute or per second for a Basic Stamp?

erco

600 RPM is pretty slow, just 10 revs/sec. You could have hundreds of pulses per rev at that speed, if you like. You can adjust your COUNT/sampling interval to give the resolution you need.

erco

Per the manual, COUNT is good up to ~125 kHz on a vanilla BS2, assuming a 50% duty cycle. So feel free to have up to 12,500 PPR. Enjoy!