Mitsubishi MELSEC-Q QD77MS, User Manual

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13 - 14
Chapter 13 Control Sub Functions
[1] Basic concept of the electronic gear
The electronic gear is an item which determines how many rotations (rotations by
how many pulses) the motor must make in order to move the machine according
to the programmed movement amount.
M
ENC
PLS
Servo
amplifier
PLS
Feedback pulse
Command
value
PLS
Control
unit
QD77MS
Machine
Reduction retio
AP
AL AM
The basic concept of the electronic gear is represented by the following
expression.
• Pr.2
(Number of pulses per rotation) = AP
• Pr.3 (Movement amount per rotation) = AL
• Pr.4 (Unit magnification) = AM
•
Movement amount per rotation that considered unit magnification =
S
AP AP
Electronic gear =
S
=
AL ×
AM
…(1)
Set values for AP, AL and AM so that this related equation is established.
However, because values to be set for AP, AL and AM have the settable range,
values calculated (reduced) from the above related equation must be contained
in the setting range for AP, AL and AM.