Mitsubishi Electronics QD75P, QD75D user manual Hardware stroke limit function

12CONTROL SUB FUNCTIONS

12.4.4 Hardware stroke limit function

MELSEC-Q

!DANGER

When the hardware stroke limit is required to be wired, ensure to wire it in the negative logic using b-contact. If it is set in positive logic using a-contact, a serious accident may occur.

In the "hardware stroke limit function", limit switches are set at the upper/lower limit of the physical moveable range, and the control is stopped (by deceleration stop) by the input of a signal from the limit switch. Damage to the machine can be prevented by stopping the control before the upper/lower limit of the physical moveable range is reached.

Hardware stroke limit switches are normally installed inside the stroke limit/stroke end on the drive unit side, and the control is stopped before the stroke limit/stoke end on the drive unit side is reached.

The details shown below explain about the "hardware stroke limit function".

[1]Control details

[2]Wiring the hardware stroke limit

[3]Precautions during control

[4]When the hardware stroke limit is not used

[1]Control details

The following drawing shows the operation of the hardware stroke limit function.

Lower limit			Upper limit
QD75 control moveable range
Mechanical stopper	Start	Start	Mechanical stopper
Movement direction			Movement direction
Deceleration stop at		Deceleration stop at
upper limit switch detection		lower limit switch detection

Drive unit stroke limit

Lower limit switch	Upper limit switch	QD75	Drive unit
			stroke limit

Drive unit

Fig. 12.19 Hardware stroke limit function operation

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