Mitsubishi Electronics QD75P, QD75D Trouble type Questions/Trouble, No. of pulses Rotation

APPENDICES

MELSEC-Q

Trouble type

Questions/Trouble

Remedy

No.

The machine only moves to

"10081230", although positioning

with a command value of

Reset

Pr.3

and

Pr.2

in the following order.

"10081234" carried out.

How can the error be

1) Calculate "8192/8000 ⋅ 10081230/10081234".

compensated?

2) Obtain the reduced value.

Error compensation The following values are currently

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set.

3) Set the numerator in "

Pr.3

Movement amount per

•

No. of pulses per

Pr.2

rotation", and the denominator in "

Pr.2

No. of pulses

rotation

8192

per rotation".

•

Pr.3

Movement amount per

rotation

8000

The near-point dog must be set to turn OFF at a position

after the OP is passed.

When carrying out a count method

(When the machine OPR is started on the near-point dog

machine OPR, the message

on in a count-method machine OPR, the machine enters

a normal machine OPR operation after returning to the

"Leave Sufficient Distance From

near-point dog OFF region.)

The OP Position To The Near-

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(If the near-point dog is turned OFF before the OP, and

Point Dog OFF." appears. Is there

a problem

the machine OPR is started between the near-point dog

OFF position and the OP, the machine will mistakenly

if the distance is short?

interpret that its current position is before the near-point

dog ON position, and it will pass over the OP and

continue moving.)

Carry out the following measures.

1)Separate the near-point dog signal and zero signal detection positions.

In the near-point dog method	2) Lower the values in "			Pr.46	OPR speed" and
machine OPR, the stop positions					20
	"	Pr.47	Creep speed".
are not uniform.

3)Confirm whether the zero signal and near-point dog signal turn ON normally.

4)Check that there is no play (backlash) in the machine

OPR			system.
	Can the machine OPR be carried	A "Hardware stroke limit error" will occur and the
	out with the OPR retry function	operation will not be carried out.
	when it is started with the near-	(The machine will interpret any position where the near-		21
	point dog ON and the upper/lower	point dog is ON as being within the working range, and
	limit OFF?	that the upper/lower limit is ON.)
	Are ABS and INC positioning	They are possible.
	possible without carrying out an	In this case, the position where the power is turned ON is		22
	OPR?	handled as the current feed value "0".
		The OPR request flag turns ON in the following cases.
		1)	When the power is turned ON.
		2)	When the PLC READY signal [YO] turns from OFF to
	After an OPR, the OPR request		ON.
	flag sometimes turns ON for no	3)	When an OPR is carried out.	23
	apparent reason.	4)	When the servo amplifier power is turned OFF.

If no problem is found when the above are checked, then it is possible that the communication is being interrupted by "a fault in the bus cable", "noise influence", etc.

The OPR complete flag

( Md.31 Status: b4) sometimes

turns ON when it shouldn't be ON.

Check whether the drive unit READY signal is weak or the power supply is unstable.

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Appendix - 94