Mitsubishi Electronics QD75D, QD75P user manual Pr.2 to Pr.4 Movement amount per pulse

5 DATA USED FOR POSITIONING CONTROL

Pr.2 to Pr.4 Movement amount per pulse

MELSEC-Q

These parameters define the amount of movement achieved by each single pulse within a pulse train output by the QD75.

The following paragraphs explain how to set the individual parameters

Pr.2

,

Pr.3

, and

Pr.4

assuming that the unit "mm" is selected with

Pr.1

.

The movement amount per pulse is given by the following expression:

Movement amount per rotation (Al)

Movement amount per pulse =

No. of pulses per rotation (Ap)

Due to the mechanical tolerance, the actual movement amount may differ slightly from the instructed movement amount. The error can be compensated by adjusting the movement amount per pulse defined here.

(Refer to Section 12.3.2 "Electronic gear function".)

POINT

If the movement amount per pulse is less than 1, command frequency variations will occur.

Smaller setting will increase variations and may cause machine vibration.

If the movement amount per pulse becomes less than 1, also use the electronic gear function of the drive unit and make setting so that the movement amount per pulse is 1 or greater.

Pr.2

No. of pulses per rotation (Ap)

Set the number of pulses required for a complete rotation of the motor shaft.

If you are using the Mitsubishi servo amplifier MR-H, MR-J2/J2S, or MR-C, set the value given as the "resolution per servomotor rotation" in the speed/position detector specifications.

No. of pulses per rotation (Ap) = Resolution per servomotor rotation

Since the "Resolution per servomotor revolution" of Mitsubishi servo amplifier MR-J2S exceeds 65535 pulses, make setting after referring to the Servo Amplifier Instruction Manual.

[Table 1]

				Value set with peripheral device	Value set with sequence program
	Pr.1	setting value
				(unit)	(unit)
0		: mm		0.1 to 6553.5 (∝ m)	1 to 65535	(⋅ 10-1∝m)
1		: inch		0.0001 to 0.65535 (inch)	1 to 65535	(⋅ 10-5inch)
2		: degree		0.00001 to 0.65535 (degree)	1 to 65535	(⋅ 10-5degree)
3		: pulse		1 to 65535 (pulse)	1 to 65535	(pulse)
1 to 32767			: Set as a decimal

32768 to 65535 : Convert into hexadecimal and set

Pr.3

Movement amount per rotation (Al),

Pr.4

Unit magnification (Am)

The amount how the workpiece moves with one motor rotation is determined by the mechanical structure.

If the worm gear lead (mm/rev) is PB and the deceleration rate is 1/n, then

Movement amount per rotation (AL) = PB ⋅ 1/n

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