Is a higher resolution encoder better?
Maybe. There are several factors in choosing an encoder: pulse rate and resolution. With the currently available PC-based CNC controllers, you are limited to a clock rate of 25khz to 45khz (Mach2). With a 250cpr encoder, you will need to generate 1,000 pulses (with quadrature) to make one full revolution. Therefore, with a 25khz clock rate, your maximum rotational speed would be 1,500rpm. With a 45khz clock rate, your maximum rotational speed would be 2,700rpm. If you go to a 500cpr encoder, your resolution will be better, but your maximum rpm will be 1/2 what you’d get with a 250cpr encoder. For example: If you have a motor geared 2:1 with a 0.200″ leadscrew, assuming your motor has enough rpm, with a 250cpr encoder and a 25khz clock rate, your resolution would be 0.0001″ and your maximum rapid speed would be 150ipm. That same motor, with a 500cpr encoder would get you 0.00005″ resolution, but your rapid speed would drop to 75ipm. At 45khz clock rate, you’d have 270ipm and 135ipm resp
