Mitsubishi MELSEC-Q QD77MS, User Manual

Page: 672 / 976

13 - 13
Chapter 13 Control Sub Functions
13.3.2 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
QD77MS.
The "electronic gear function" has the following three functions ( [A] to [C] ).
[A] During machine movement, the function increments in the QD77MS 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 OPR 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 QD77MS automatically carries out the processing for [A] and [B].
The details shown below explain about the "electronic gear function", including the
method for compensating the error in [C] above, etc.
[1] Basic concept of the electronic gear
[2] The method for compensating the error