
B-63783EN-1/01 14.PMC CONTROL FUNCTION
- 1435 -
3) Reset signal RSTx is set to 1.
4) A servo alarm is issued.
5) An OT alarm is issued on an axis subjected to torque
control.
6) An emergency stop occurred.
7) A controlled-axis is detached by controlled axis detach
signal DTCHx or the setting parameter.
8) The servo motor is turned off by servo off signal *SVFx.
a. Timing for canceling torque control
Torque control in PMC axis control is canceled in different
ways depending on whether bit 3 (TQF) of parameter No.
1409 specifies follow-up. If follow-up is specified by
parameter setting, satisfying any cancellation condition
immediately sets the torque control mode signal TRQMx to
0, and position control mode is set again. Then, after the
positional deviation enters the in-position state, execution
terminates. If follow-up is not specified by parameter setting,
satisfying any cancellation condition sets the torque control
mode signal TRQMx to 0, after which follow-up starts.
When the positional deviation becomes equal to or less than
the cancellation limit set in parameter No. 7768, position
control is resumed. After the positional deviation enters the
in-position state, execution terminates.
b. Command after cancellation
After torque control mode is canceled, normal position
control is resumed. Since position management is performed
in torque control mode, the machine coordinates are not
shifted. Workpiece coordinates and machine coordinates,
however, shift. Therefore, the shift amount must be canceled
by, for example, workpiece coordinate system presetting.
CAUTION
1 When a movement is made along a torque-
controlled axis in torque control mode, set bit 3
(TQF) of parameter No. 1409 to 1 to perform
follow-up.
2 If torque control is canceled while a movement is
being made along a torque-controlled axis, a
mechanical shock is generated upon switching from
torque control to position control. As the speed of
the movement increases, the degree of the shock
becomes larger. Therefore, before canceling torque
control, decelerate the movement to the lowest
speed possible, or stop the movement.
3 In torque control mode, do not detach a controlled
axis by issuing controlled-axis detach signal DTCHx
or using the setting parameter.