EMC - Tuning Stepper rates?

I have EMC running on a Linux machine and I
am successfully moving my x axis stepper.

But the step rate is too high for the motor. In emc.ini,
I see I can set things like the default velocity, max velocity but
I don't see anything about limiting the step rate (like
MAX_STEPS_PER_SECOND = 50)

Does anyone know of a good tutorial on tuning these parameters
for particular stepping motors?

Thanks,
Art