
17.PMC CONTROL FUNCTION B-63943EN-1/02
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value of the error counter exceeds the value set in parameter
No. 1885. At the time of switching back to position control,
follow-up operation is performed.
If the error counter is not updated (with bit 1 (TRE) of
parameter No. 1805 set to 1), no errors are accumulated, so
that no servo alarm is issued. However, when the maximum
allowable speed is exceeded, the alarm (SV0422) is issued.
When this setting is selected, a reference position return
operation is required to switch back to position control.
Except when bit 4 (TQF) of parameter No. 1803 is set to 0,
and bit 1 (TRE) of parameter No. 1805 is se to 1, the CNC
always exercises position control even in the torque control
mode. So, no reference position return operation needs to be
performed even at the time of switching from torque control to
position control.
c. Movement direction and speed in the torque control mode
In the torque control mode, the output of torque specified by
the axis control data signals EID0g to EID31g is attempted.
However, when there is no torque generation target or the
output has not reached the specified torque data yet, a
movement is made in the same direction as in the case of
position control according to the +/- sign of torque data.
When the move speed exceeds the specified value, the
alarm (SV0422) is issued.
d. Timing of switching to torque control
Switching to the torque control mode from another mode
occurs when the position deviation is decreased to within the
in-position width.
e. In the torque control mode, the torque control mode signal
TRQMx is set to 1. (For details of this signal, see "Signal
detail".)
(2) Switching from torque control to position control
(Torque control mode cancellation)
When any of the following conditions occurs, the torque
control mode ends:
1) When the reset signal ECLRg is set to 1
2) When a servo alarm is issued
3) When an OT alarm is issued with an axis placed under
torque control
4) At the time of emergency stop
5) When servo-off occurs due to the servo-off signal
ESOFg
a. Timing of torque control cancellation
The cancellation of torque control based on PMC axis
control depends on whether to perform follow-up operation
as determined by bit 4 (TQF) of parameter No. 1803.
If follow-up operation is performed (with bit 4 (TQF) of
parameter No. 1803 set to 1), the torque control mode signal
TRQMx is set to 0 to return to position control immediately
when a cancellation condition occurs. The execution then