Mitsubishi Electric MELSEC-Q-MR-JE-C Reference Manual page 41

Function overview
Item Description
Applicable hardware and Applicable CPU
software
Applicable engineering tool
Language Structured Text
Number of basic steps 986 steps
Function description This FB controls the velocity of the specified axis to the commanded velocity.
This FB is executed when Execute turns ON, and Busy turns ON when the processing is normally started.
When the mode of the axis changes to the velocity control mode, Active turns ON. When the velocity of the axis has
reached the commanded velocity, InVelocity turns ON.
Once InVelocity turns ON when the velocity of the axis has reached the commanded velocity, InVelocity remains ON until
Execute turns OFF or the control is aborted.
The actual rotation direction depends on the sign specified with the commanded velocity (Velocity) and the setting of the
rotation direction (Direction).
The axis status transits to ContinuousMotion.
Abort the execution of the FB and switch the control by executing another MC_MoveVelocity or MC_TorqueControl.
To stop the operation, use MC_Halt. When the control is aborted, CommandAborted turns ON.
When Execute turns OFF, CommandAborted turns OFF.
When an error has occurred in the FB, this FB turns ON Error and stores an error code in ErrorID.
For details of error codes, refer to  Page 61 Troubleshooting.
Restrictions and precautions
FB operation type Pulsed execution (multiple scan execution type)
• Before executing this FB, set the torque limit value (PositiveTorqueLimit, NegativeTorqueLimit) of the AXIS_REF
structure.
• When the positioning control FB is in execution (AxisStatus is DiscreteMotion), execute this FB with the axis stopped.
• When the mode is switched from the velocity control mode to the torque control mode, the servo motor speed may
momentarily fluctuate. Thus, it is recommended switching the mode from the velocity control mode to the torque control
mode after the servo motor is stopped.
QnUDVCPU
GX Works2
3 FB LIBRARY
3.2 Details of the FB Library
3
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