HEIDENHAIN iTNC 530 Service Manual page 112

Detail 6, 10 or 12 digital speed controllers for the axes and spindle(s) are integrated in the iTNC 530:
speed controller
The actual speed values are measured directly at the motors with HEIDENHAIN rotary encoders.
The position controller provides the nominal speed value. The speed controller is driven by the
difference between nominal and actual speed values. It provides the nominal current value as
output.
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