Mitsubishi Electronics QD75P, QD75D user manual Speed Control

APPENDICES

MELSEC-Q

SPEED CONTROL

Speed control is mainly carried out with the servomotor. It is an application for grindstone rotation, welding speed, feedrate, etc. Speed control differs from position control in that the current position (address) is not controlled. Drive units may differ, even when the same motor is used.

SPEED INTEGRAL COMPENSATION

This is one item in the parameters of the servo amplifier, and is used to raise the frequency response during speed control to improve transient characteristics.

When adjusting the speed loop gain, raising this value is effective if the overshooting during acceleration/deceleration remains large.

This compensation is set in ms units.

SPEED-POSITION SWITCHING CONTROL

With this control, positioning is carried out to the end point of the movement amount while changing the speed at the speed switching point during positioning control.

SPEED-POSITION SWITCHING CONTROL MODE

This is one method used for positioning. It is an application for operations such as high- speed movement to a point unrelated to positioning, then set dimension movement from the switching signal activation point.

Start	Switching signal
High speed	Incremental positioning

SPEED LIMIT VALUE

This is the max. speed for positioning. Even if other data is mistakenly set to a higher speed than this, the positioning will be carried out at this speed limit value when it is set in the parameters. The acceleration time becomes the time to accelerate from a stopped state to the speed limit value, and the deceleration time becomes the time to decelerate from the speed limit value to a stopped state.

SPEED LOOP GAIN

This is one item in the parameters of the servo amplifier, and expresses the speed of the control response during speed control. When the load inertia moment ratio increases, the control system speed response decreases and the operation may become unstable. If this happens, the operation can be improved by raising this setting value.

The overshoot will become larger if the speed loop gain is raised too far, and motor vibration noise will occur during operation and when stopped.

SPEED LOOP MODE

This is one servo control mode used in positioning. It is a mode for carrying out speed control. Refer to "POSITION LOOP MODE".

START COMPLETE

This signal gives an immediate response notifying the user that the QD75 that was started is now in a normal state and can start positioning.

STARTING AXIS

One of the QD75 axis system axes (axis 1, axis 2, axis 3, or axis 4) or the reference axis for the interpolation operation is designated as the starting axis.

STATUS

Data showing the state of the machine. Collectively refers to signals that turn ON when the battery voltage drops, during OPR requests, during dwell time, etc.

STEP FUNCTION

When the operation is designed so that several positioning data Nos. are consecutively run, this function can be used to carry out a test operation for 1 data item at a time.

Appendix - 88