6.23.13 Home position return retry function. Mitsubishi MOTION CONTROLLERS Q172DCPU

6 POSITIONING CONTROL

6.23.13 Home position return retry function

When a work has been exceeded home position during positioning control, etc., even if it executes the home position return, depending on the position of work, a work may not travel to home position direction. In this case, a work is normally travelled before the proximity dog by the JOG operation, etc, and the home position return is started again. However, by using the home position return retry function, even if a work is where, the home position return can be executed.

Refer to Section 6.23.1(7) for home position return method by using the home position return retry function.

[Data Setting]

When the "home position return retry function" is used, set the following "home position return data" using MT Developer.

Set the "dwell time at the home position return retry" as required.

Set the parameters for every axis.

Table 6.4 Home position return data

Items Setting

Setting value

Home position return retry function

0 : Invalid (Do not execute the home position return retry by limit switch.)

1 : Valid (Execute the home position return retry by limit switch.)

0, 1

Initial value

0

Dwell time at the home position return retry

The stop time at the deceleration stop during the home position return retry is set

0 to 5000

[ms]

0

[Control details]

Operation for the home position return retry function is shown below.

(1) Home position return retry operation setting a work within the range of external limit switch

Acceleration time Deceleration time

5)

4)

Proximity dog

Home position return direction

6)

Home position

1)

Home position return start

3)

2)

External limit switch

1) It travels to preset direction of

home position return.

2) If the external upper/lower

limit switch turns OFF before

the detection of proximity dog, a deceleration stop is made.

3) After a deceleration stop, it

travels to reverse direction of

home position return with the

home position return speed.

4) A deceleration stop is made by

the proximity dog OFF.

5) After a deceleration stop, it

travels to direction of home

position return.

6) Home position return ends.

Zero point

Fig. 6.44 Operation for home position return retry (proximity dog type)

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(2) Home position return retry operation setting a work outside the range of external limit switch

(a) When the direction of "work home position" and home position return is same, normal home position return is operated.

Direction of "work home position" and home position return is same

Home position return direction

Home position return start

RLS

Proximity dog

FLS

Home position

Zero point

Travel range

(b) When the direction of "work home position" and home position return is reverse, deceleration stop is made with the proximity dog OFF and home position return is operated to preset direction of home position return.

Direction of "work home position" and home position return is reverse

1) It travels to preset reverse direction of home position

return with the home position return speed.

2) A deceleration stop is made by the proximity dog OFF.

3) After a deceleration stop, it travels to direction of home

position return, the home position return ends.

Home position return direction

3)

Home position return start

RLS

2)

Proximity dog

Home position

1)

Zero point

FLS

Travel range

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(3) Dwell time setting at the home position return retry

Reverse operation by detection of the external upper/lower limit switch and dwell time function at the home position return start after stop by proximity dog OFF are possible with the dwell time at the home position return retry in the home position return retry function.

Dwell time at the home position return retry becomes valid at the time of deceleration stop of the following 2) and 4). (Dwell time operates with the same value.)

Home position return direction

The temporary stop is made during time set in the "dwell time at the home position return retry".

5)

6)

1)

2)

[Cautions]

4)

Home position

Home position return start

3)

External limit switch

Proximity dog

The temporary stop is made during time set in the "dwell time at the home position return retry".

1) It travels to preset direction of home position return.

2) If the external upper/lower limit switch turns OFF

before the detection of proximity dog, a deceleration

is made and the temporary stop is made during time

set in the "dwell time at the home position return

retry".

3) After a stop, it travels to reverse direction of home

position return with the home position return speed.

4) A deceleration is made by the proximity dog OFF

and the temporary stop is made during time set in

the "dwell time at the home position return retry".

5) After a stop, it travels to direction of home position

return.

6) Home position return ends. At this time, the "dwell

time at the home position return retry" is invalid.

Fig. 6.45 Dwell time setting at the home position return retry

Zero point

(1) Possible/not possible of home position return retry function by the home position return method is shown below.

Home position return methods

Proximity dog type

Count type

Data set type

Dog cradle type

Stopper type

Limit switch combined type

Possible/not possible of home position return retry function

: Possible, : Not possible

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(2) Make a system for which does not execute the servo amplifier power off or servo

OFF by the external upper/lower limit switch. Home position return retry cannot be executed only in the state of servo ON.

(3) Deceleration is made by detection of the external limit switch and travel to reverse direction of home position return is started. In this case, a major error "external limit switch detection error" (error codes: 1001, 1002, 1101, 1102) will not occur.

CAUTION

Be sure to set the external limit switch (FLS, RLS) in the upper/lower position of machines. If the home position return retry function is used without external limit switch, servomotors continue rotating.

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