Electronic Gear Function - Mitsubishi Electric MELSEC iQ-R Series User Manual

Electronic gear function

The "electronic gear function" adjusts the actual machine movement amount and number of pulse output to servo amplifier
according to the parameters set in the Motion module.
The "electronic gear function" has the following three functions ([A] to [C]).
[A] During machine movement, the function increments in the Motion module values less than one pulse that could not be
output, and outputs the incremented amount when the total incremented value reached one pulse or more.
[B] When machine home position return is completed, current value changing is completed, speed control is started (except
when feed current value is updated), or fixed-feed control is started, the function clears to "0" the cumulative values of less
than one pulse which could not be output. (If the cumulative value is cleared, an error will occur by a cleared amount in the
feed machine value. Control can be constantly carried out at the same machine movement amount, even when the fixed-feed
control is continued.)
[C] The function compensates the mechanical system error of the command movement amount and actual movement amount
by adjusting the "electronic gear". (The "movement amount per pulse" value is defined by "[Pr.2] Number of pulses per
rotation (AP)", "[Pr.3] Movement amount per rotation (AL)" and "[Pr.4] Unit magnification (AM)".)
The Motion module automatically carries out the processing for [A] and [B].
The "electronic gear function" in this section is different from the "electronic gear function" of the servo amplifier. For the
"electronic gear function" of the servo amplifier, refer to the manual of the servo amplifier.
Precautions
Depending on the resolution of the encoder, there may be limitations in the electronic gear setting of servo amplifier. For
details, refer to the following.
Page 658 Devices Compatible with CC-Link IE TSN
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.
Motion module
Command
Control
unit
value
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
Electronic gear
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.
8 CONTROL SUB FUNCTIONS
226
8.2 Functions for Compensating the Control
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AP
Pulse
AL × AM
AP AP
= =
... (1)
S AL × AM
search engine
Reduction gear
Pulse
Servo amplifier
M
ENC
Pulse
Feedback pulse
Machine