The Control Loop - HEIDENHAIN iTNC 530 HSCI Technical Manual

6.8 The control loop

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Machine tools normally function on the principle of cascade control. Here the
position control loop is prior to the speed and current control loops.
Benefits of cascade control:
 Transparent structure of the individual control loops
Disturbances can be compensated through the subsequent controllers. This

relieves the prior controller.
The respective outer control loop protects the inner control loop by limiting

the command variable.
Individual commissioning of each control loop, starting with the innermost

loop.
The position, speed, and current controllers, and the power module are
integrated in the iTNC. The power module is driven by the CC 6xxx through
PWM signals (PWM = pulse width modulation).
The iTNC 530 controls machines with up to 18 axes and 2 spindles. Spindle
speeds up to 40 000 min
–1
for motors with two pole pairs are possible.
HEIDENHAIN Technical Manual iTNC 530 HSCI