# Electronic Gear Function - Mitsubishi Electric RD77MS2 User Manual

Melsec iq-r simple motion module.

## 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 Simple Motion module.
The "electronic gear function" has the following three functions ( [A] to [C] ).
[A] During machine movement, the function increments in the Simple 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 current feed value change is present), 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 Simple Motion module automatically carries out the processing for [A] and [B].
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.
Simple Motion module
Command
Control
unit
value
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
Electronic gear
=
ΔS
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.
Servo
AP
pulse
amplifier
Feedback pulse
AP
=
(1)
AL × AM
Reduction ratio
pulse
M
ENC
pulse
8.3 Functions for Compensating the Control
Machine
8 CONTROL SUB FUNCTIONS
8
225

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