Siemens SIMATIC S5 Manual page 269

Planning
The transmission ratio r on the spindIe and the step number S of the motor must be selected so
that their quotient produces the required resolution.
The maximum pulse frequency f~ti is obtained as follows:
----------------------
k ~ 60 [p m/pul]
From the characteristics of the motors, you must now select a type capable of the required load
torque at the calculated frequency fnl~ without loss of steps. You must also select a suitable
power unit for the motor.
7 - 2
s=