Mitsubishi Electronics QD75P Torque width variations, deviations in the torque, Limit switch

APPENDICES

MELSEC-Q

STROKE LIMIT

This is the range in which a positioning operation is possible, or the range in which the machine can be moved without damage occurring.

(Movement outside this range is possible in the manual operation.) For operations using a worm gear, the stroke limit is determined by the length of the screw. For operations using a fixed-feed, it is determined by the max. dimension to be cut.

The upper and lower limits are set in the parameters, but a separate limit switch should be established and an emergency stop circuit outside the PLC should be created. Refer to the term "LIMIT SWITCH".

		Limit switch
		for emergency
Lower limit	Upper limit	stop
0	3m (9.84feet)

Positioning possible in a 3m (9.84feet) range

TORQUE CONTROL

In this function, a limit is established for the resistance torque applied to the motor used for positioning. The power is turned OFF if torque exceeding that value is applied to the motor. When excessive torque is applied to a motor, it causes the current to suddenly increase. Motor burning and other stress on the motor occurs, and the life of the motor is shortened.

This function utilizes the sudden increase in the torque when the machine OPR to issue a command to stop the motor.

TORQUE LOOP MODE

Also called the current loop mode. Refer to "POSITIONING LOOP MODE".

TORQUE RIPPLE

Torque width variations, deviations in the torque.

SUDDEN STOP

A stop carried out in a shorter time than the deceleration time designated in the parameters.

Full speed

Sudden stop

Time

Deceleration time

TEACHING

When the positioning address is uncertain, or gauging is required, this function is used by the user to search for and teach the position to the machine.

For example, complex addresses such as drawings can be taught by tracing a model, and the positioning operation can be reproduced.

TRACKING FUNCTION

In this function, positioning is carried out at a speed relative to a moving target object by inputting the movement amount from an external encoder and adding it to the servo command value.

Appendix - 90