Servo Positioning Of The Nc-Axes; The Position Control Loop Of An Nc-Machine - HEIDENHAIN TNC 415 Technical Manual

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3 Servo positioning of the NC-axes

This section describes all the control functions which are important for the control and monitoring of
the NC-axes .
Further parameters for the NC-axes can be found under "Machine axes".
The control of the main spindle (S-axis) is described under "Main spindle".

3.1 The position control loop of an NC-machine

In CNC machines the servo control is normally implemented as a cascade control (see following
block diagram).
The motor speed control and the current control (both in the drive amplifier) are integrated into the
servo position control (CNC-control). The servo controlled system consists of the motor and machine
slide.
CNC Control
Nom.
Position
Nom. Servo
controller
rpm
pos. lag
Block diagram of the position control loop, here as a cascade control
01.98 TNC 407/TNC 415/TNC 425
Servo amplifier
Nom.
Speed Current
regulator
controller
cur.
3 Servo positioning of the NC-axes
Machine
Drive Tacho
Linear/
angle
encoder
4-65