Resolution question

[pstockley]

Assuming a servo has a 2500 count quadrature encoder does this mean the servo has a resolution of 1/10,000 of a revolution?

Also I am considering connecting some AC servos directly to my ballscrews. I hear that AC servos can exhibit cogging at low speed. Is this true? If so, how slow can they run smoothly?

[Al_The_Man]

Some tend to use the term quadrature for the 4x encoder count, actually the term quadrature refers to the type of decoding, ie. two chanels phase shifted 90deg, hence the term quadrature. The two phase signals can then be decoded by counting x1 the resolution or both leading edges (x2) or both leading and trailing edges (x4) . These magnifications increase the base resolution by the multiplier.
DC brushless exhibit some cogging at low speed, AC sinusoidal virtually none.
Al.