The Control Loop - HEIDENHAIN iTNC 530 Technical Manual

6.8 The Control Loop

iTNC 530
February 2002
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:
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Transparent structure of the individual control loops.
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Disturbances can be compensated through the subsequent controllers. This
relieves the prior controller.
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The respective outer control loop protects the inner control loop by limiting
the command variable.
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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 422 through
PWM signals (PWM = pulse width modulation).
The iTNC 530 controls machines with up to 9 axes and a spindle or up to 8
axes and 2 spindles. Spindle speeds up to 40 000 rpm for motors with two
pole pairs are possible.
The Control Loop 6 – 109