Tuning Of The Drive Amplifier - HEIDENHAIN TNC 415 Technical Manual

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Tuning of the drive amplifier:

As far as the control is concerned, the actual servo-loop consists of the drive amplifier, motor
and axis slide (see section "Servo positioning"). The servo-loop must be tuned before the position
control loop in the control can be optimized.
To achieve this, a battery supply is used to apply a (9 V) step function to the nominal value input
of the drive amplifier. The step response can be recorded by an oscilloscope via the tachometer
signal. The axis should be loaded with the permissible workpiece weight during the acquisition of
the step response. The subordinate control loop (current control, spindle speed control) must be
so optimized that the step response shows an overshoot. The following picture shows the ideal
response of the tacho-signal.
Given step
function
U [V]
U
max
T
The following pictures show incorrectly adjusted tacho-signals:
U [V]
U
max
The P-component of the subordinate control loop is too high, or the I-component too low.
U [V]
U
max
The P-component of the subordinate control loop is too low, or the I-component too high..
01.98 TNC 407/TNC 415/TNC 425
1 Overshoot
Tacho-signal
Several overshoots
Incorrect!
Too flat
Incorrect!
t [ms]
16 Commissioning and start-up procedure
t [ms]
t [ms]
4-259