Mitsubishi Electronics MR-J2S- CL specifications Dog type rear end reference home position return

4. OPERATION

4.4.7 Dog type rear end reference home position return

POINT

This home position return method depends on the timing of reading Proximity dog (DOG) that has detected the rear end of a proximity dog. Hence, if a home position return is made at the creep speed of 100r/min, an error of 200 pulses will occur in the home position. The error of the home position is larger as the creep speed is higher.

The position where the axis, which had started decelerating at the front end of a proximity dog, has moved the after-proximity dog moving distance and home position shift distance after it passed the rear end is defined as a home position. A home position return that does not depend on the Z-phase signal can be made.

(1)Signals, parameters

Set the input signals and parameters as indicated below.

Item	Device/Parameter used	Description
Manual home position return mode	Automatic/manual selection (MD0)	MD0 is switched on.
selection
Dog type rear end reference home	Parameter No.8	5: Select the dog type rear end reference.
position return
Home position return direction	Parameter No.8	Refer to Section 4.4.1 (2) in this section and select the home
		position return direction.
Dog input polarity	Parameter No.8	Refer to Section 4.4.1 (2) in this section and select the dog input
		polarity.
Home position return speed	Parameter No.9	Set the speed till the dog is detected.
Creep speed	Parameter No.10	Set the speed after the dog is detected.
Home position shift distance	Parameter No.11	Set when the home position is moved from where the axis has
		passed the proximity dog rear end.
Moving distance after proximity dog	Parameter No.43	Set the moving distance after the axis has passed the proximity dog
		rear end.
Home position return acceleration/	Parameter No.41	Use the acceleration/deceleration time constants set in parameter
deceleration time constants		No. 41.
Home position return position data	Parameter No.42	Used to set the current position on completion of home position
		return.
	Select the program including the
Program	"ZRT" command that executes a
	home position return.

(2)Timing chart

The following shows the timing chart that starts after selection of the program including the "ZRT" command.

Automatic/manual ON selection (MD0) OFF

Movement complete (PED)	ON
	OFF
Home position return	ON
completion (ZP)	OFF

		Home position return speed	Moving distance after proximity dog
			Home position shift distance
Forward			Creep speed
Servo motor speed rotation		3ms or less
0 r/min				Home position address
			Proximity dog
				Parameter No. 42
Proximity dog (DOG)	ON
	OFF
Forward rotation start (ST1)	ON
	OFF

5ms or more

The address on completion of home position return is the value automatically set in parameter No.42 (home position return position data).

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