HEIDENHAIN TNC 335 Technical Manual - Manual (Page 325)

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TNC 360 16 Commissioning and Start-up Procedure 8/95
– 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 of the tachometer signal can be recorded by an
oscillograph. 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.
U [V]
t [ms]
U
max
T
Tacho-signal
1 Overshoot
Given step
function
Correct
The following pictures show incorrectly adjusted tacho-signals:
U [V]
t [ms]
U
max
Several overshoots
Incorrect!
Incorrect
The P component of the subordinate control loop is too high, or the I component too low.