
4. SERVO FUNCTION DETAILS B-65150E/04
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(iii) Torque command when overshoot compensation is used
Function bit
OVSC = 1 (Overshoot compensation is valid)
Parameter
PK3V: around 30000 to 25000 (Incomplete integral coefficient)
(Example)
when PK3V=32000 time constant approx. 42 msec
when PK3V=30000 time constant approx. 11 msec
when PK3V=25000 time constant approx. 4 msec
Fig. 4.7 (f) Torque command (when overshoot is used)
If this overshoot compensation function is used, it is possible
to prevent overshoot so that the relationship between
machine static and non–static friction and TCMD2 satisfies
<1>, however the torque TCMD during machine stop is
TCMD2 = 0
the servo rigidity during machine stop is insufficient and it is
possible that there will be some unsteadiness at ±1 pulse
during machine stop.
There is an additional function to prevent this unsteadiness
in the improved type overshoot prevention function and the
status of the torque command at that time is shown in (iv).
TCMD1
TCMD2
Torque command (TCMD)
Static friction
Time
Non-static friction
This time constant
is fixed at the
PK3V value.