Mitsubishi Electric MELSEC-L LD75D, User Manual

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12.3.2
Electronic gear function
The "electronic gear function" adjusts the pulses calculated and output according to the parameters set in the LD75
with the actual machine movement amount.
The "electronic gear function" has the following four functions.
*1 Unit specified with "[Pr.1] Unit setting" (mm, inch, degree, pulse)
The LD75 automatically carries out the processing for [A] to [C].
The details shown below explain about the "electronic gear function", including the method for compensating the error
in [D] above, etc.
• Movement amount per pulse
• Error compensation method
• Control precautions
[A] The function converts the command value (speed, movement amount from the start point to the end point),
which is set in mm units, to pulse units, and determines the pulse frequency and number of the command pulse.
[B] If values less than one pulse are generated by converting the movement amount from the start point to the end
point to pulse units, the values are not output and the machine stops at the front side of the positioning direction.
The function accumulates values less than one pulse that were not output in the LD75 and outputs one pulse
when the total cumulative value has reached one pulse or more.
[C] 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.)
[D] The function compensates the mechanical system error of the command movement amount and actual
movement amount by adjusting the "movement amount per pulse". (The "movement amount per pulse" value is
defined by "[Pr.2] No. of pulses per rotation (Ap)", "[Pr.3] Movement amount per rotation (Al)", and "[Pr.4] Unit
magnification (Am)".)
LD75
Command output pulses
Set value in each unit *1.
Speed: V
Movement amount: L
Speed: Frequency
Movement amount: Number
of pulses
Command value
CPU module,
GX Works2
Electronic
gear