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12 CONTROL SUB FUNCTIONS
[2] The method for compensating the error
When the position control is carried out using the "Electronic gear" set in a
parameter, this may produce an error between the command movement amount
(L) and the actual movement amount (L'). With QD75MH, this error is
compensated by adjusting the electronic gear. The "Error compensation
amount", which is used for error compensation, is defined as follows:
Error compensation amount =
The electronic gear including an error compensation amount is shown
below.
AP
×
AL × AM
QD75MH
Control
Command
unit
value
QD75MH
Command
Control
value
unit
Calculation example
(Conditions)
Movement amount per pulse
No. of pulses per rotation
Unit magnification
(Positioning results)
Command movement amount (L)
Actual movement amount (L')
(Compensation
AP
×
AL × AM
Movement amount per pulse
No. of pulses per rotation
Unit magnification
Set the post-compensation "
Pr.3
"
Movement amount per rotation (AL')", and "
magnification (AM')" in the parameters, and write them to the QD75MH.
The set details are validated at the rising edge (OFF
READY signal (Y0).
Command movement amount (L)
Actual movement amount (L')
L
AP'
=
L'
AL' × AM'
AP
AL AM
1 if there is no error (in regular case)
Electronic gear taking an error
into consideration
AP'
AL' AM'
: 262144 [PLS]
: 5000.0 [ µ m]
: 1
: 100 [mm]
: 101 [mm]
L
262144
100
×
=
5000.0 × 1
L'
101
: 262144 ... Pr.2
: 5050.0 .... Pr.3
: 1 ............ Pr.4
Pr.2
12 - 19
Servo
L
PLS
amplifier
L'
Servo
PLS
amplifier
262144 (AP')
=
5050 (AL') × 1(AM')
No. of pulses per rotation (AP')",
Pr.4
ON) of the PLC
MELSEC-Q
...(2)
Unit
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