Hello, i have a project im working on (Not a CNC machine, but i believe a Mesa card is good capable hardware for this application) where im trying to determine the rate of acceleration of an externally driven spindle using an encoder. 

There doesn't seem to be any built in components for this that i can find.

The use case, is to feed the rate of acceleration into a PID loop to control the output of a stepper/servo that regulates the spindles speed.

Is there a relatively easy way to measure/determine rate of acceleration accurately?