6.23.6 Home position return by the count type 3. Mitsubishi MOTION CONTROLLERS Q172DCPU

6 POSITIONING CONTROL

6.23.6 Home position return by the count type 3

(1) Count type 3

After the proximity dog ON, the zero point after the specified distance (travel value after proximity dog ON) is home position in this method. (If the proximity dog signal of servo amplifier is used, the count type 3 home position return cannot be executed.)

When the zero point is passed (zero pass signal: M2406+20n ON) during travel of specified distance set in the "travel value after proximity dog ON" from the home position return start, home position return operation is the same as "count type 1". (Refer to Section 6.23.4)

When a zero point is not passed (zero pass signal: M2406+20n OFF) during travel of specified distance set in the "travel value after proximity dog ON" from the home position return start, it rotates one time to reverse direction and passes the zero point, re-travels to home position return direction, and then the first zero point after the specified distance (travel value after proximity dog ON) after proximity dog ON is set as home position.

The travel value after proximity dog ON is set in the home position return data

(Refer to Section 6.23.1).

V

Home position return speed

1)

(2) Home position return by the count type 3

Operation of home position return by count type 3 for not passing the zero point during travel of specified distance set in the "travel value after proximity dog ON" from the home position return start is shown below.

Home position return direction

Home position return start

2)

4)

Home position return speed

1 revolution

Proximity dog

Zero point no passing

3)

5)

Creep speed

Home position

Zero point

1) It travels to preset direction of home

position return with the home position

return speed.

2) A deceleration is made to the creep speed

by the proximity dog ON, after that, it

travels with the creep speed.

3) A deceleration stop is made in the position

which traveled the travel value set as travel value after proximity dog ON.

4) After a deceleration stop, it travels for one

revolution of servomotor to reverse

direction of home position return with the

home position return speed.

5) It travels to direction of home position

return with the home position return speed,

the home position return with first zero point after traveling the travel value set as travel value after proximity dog ON from after the proximity dog ON.

(At this time, a deceleration to the creep

speed is not made with the proximity dog

OFF to ON. And if the zero point is not

passed because of droop pulses for

processing of 4) and 5), a minor error "ZCT

not set" (error code: 120) will occur, a

deceleration stop is made and home

position return does not end normally. In

this case, adjust a position of proximity dog

ON.)

The travel value in this range is stored in the monitor register "travel value after proximity dog ON".

The travel value in this range is stored in the monitor register "home position return re-travel value".

Fig. 6.37 Home position return operation by the count type 3 (zero point no passing)

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6 POSITIONING CONTROL

(3) Home position return execution

Home position return by the count type 3 is executed using the servo program in

Section 6.23.16.

(4) Cautions

(a) A system which the servomotor can rotate one time or more is required.

(b) After the proximity dog ON, when a servomotor rotates one time to reverse direction after stop with travel value set in the "travel value after proximity dog ON", make a system which does not turn OFF the external upper/lower stroke limit.

(c) Home position return and continuously start of home position return are also possible in the proximity dog ON in the count type 3.

When the home position return and continuously start of home position return are executed in the proximity dog ON, the home position return is executed after return the axis once to position of the proximity dog OFF.

(d) When the "travel value after proximity dog ON" is less than the deceleration distance from "home position return speed" to "creep speed", a minor error

"an overrun occurred because the setting travel value is less than the deceleration distance at the proximity dog signal input during home position return of count type." (error code: 209) will occur and deceleration stop is made.

(e) When "1 : Not need to pass motor Z phase after the power supply is switched on" is selected in the "function selection C-4" of servo parameter

(expansion setting parameter), even if it does not pass zero point at the servo amplifier power ON, the zero pass signal (M2406+20n) turns ON. This operation is the same as count type 1.

(f) If in-position signal (M2402+20n) does not turn ON, home position return is not ended.

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