tachometer and motor PID control on same chip ?

Hi thar

I'm making a PID controller speed regulator eventually to be used in a record player. Trouble is the output is jittery and unreliable. I have an alrite tachometer code, and I'm wondering if tachometer and PID on the same chip is maybe too much?

It's certainly doing my head in trying to make the PID work without disturbing the timing and whatnot of the tachometer

http://arduino.cc/forum/index.php?topic=50019 here be the tacho code, and the PID bit is just a P chucked in where RPM is evaluated. not shown cuz its darn messy.

what do you think? too much or am i just too nooby?

sounds like a reasonable project. what is rotating the platform and how are you controlling it?

all the other resistors and messy wires are for some switches a foot away

Hi, I recently asked about this topic and got little to no response other than to sod off and go Google it my self. If you have any information regarding this project and how it went please let me know.

Don't see why you need a processor for this - a bit of simple analog circuitry would be fine.

to help further I need to know..

  • what speed sensor are you using?
  • what are the motor characteristics..

I'm afraid your photo link didn't work.

by the way, when I studied control theory years ago, such a setup was called a 'velodyne'

regards

Allan

ps years ago in the vinyl days, nost turntables used a near-synchronous motor which locked to the mains frequency - perfectly adequate.