Omron CJ1W-NC271 - 12-2009, Operation Manual

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Torque Control
Section 10-6
Changes in Torque when
Switching Control Modes When switching to another control mode during torque control, position con-
trol with the torque limit enabled, or speed control, the torque in the control
mode to be switched to must be considered. For example, if DECELERATION
STOP is executed with the torque limit disabled during speed control with the
torque limit enabled, position control will be used without the output torque
limit during the time deceleration stop is executed.
When switching from the control mode that requires a constant torque limit,
such as for pushing or pulling a load, make sure that the torque limit is also
enabled for the next operating command to be executed to prevent a sudden
change in output torque.
Note In speed control mode, axis stop operations due to errors are executed after
switching to position control. The torque limit for these stop operations
depends on the setting of the Current Limit Designation Bit at when the error
occurred. When executing speed control with the torque limit enabled using
the option command value, if the Current Limit Designation Bit is not set to
ON, the axis stop operation due to error will be executed with the torque limit
disabled. To enable the torque limit for axis stop operations due to errors, turn
ON the Current Limit Designation Bit and set Servo Parameters
No.1 Torque
Limit (Pn013) or No.2 Torque Limit (Pn522) when using G5-series Servo
Drives, Servo Parameters No.1 Torque Limit (Pn05E) or No.2 Torque Limit
(Pn05F) when using G-series Servo Drives, and Forward Rotation External
Current Limit (Pn404) or Reverse Rotation External Current Limit (Pn405)
when using W-series Servo Drives.
10-6 Torque Control
10-6-1 Overview
In torque control, the PCU controls the output torque of the Servomotor by
directly executing torque commands in a torque (current) loop without using
the Servo Drive's position loop or speed loop.
Torque control can be used when a G5-series Servo Drive, a G-series Servo
Drive or a W-series Servo Drive is connected. The SMARTSTEP Junior Servo
Drives do not support torque control.
10-6-2 Starting Torque Control
Torque control is performed according to the target torque set in the torque
command value in the Axis Operating Output Memory Areas and started
when the TORQUE CONTROL Bit turns ON. When starting torque control,
make sure that the TORQUE CONTROL Bit remains ON until the Receiving
Command Flag or Busy Flag in the Axis Operating Input Memory Area turns
ON.
If the SERVO UNLOCK, DEVIATION COUNTER RESET, EMERGENCY
STOP, OR DECELERATION STOP command bit is turned ON, the TORQUE
CONTROL command will be ignored. Be sure that all of these command bits
are OFF before executing torque control.
The torque command value is set in units of 0.001% as a percentage of the
Servomotor's momentary maximum torque. The torque command value is
specified in the range
−
199.999% to 199.999%, and the rotation direction is
determined by the sign (positive or negative) of the torque command value.
The actual Servomotor torque control range and minimum control unit depend
on the Servo Drive specifications.