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12 CONTROL SUB FUNCTIONS
[1] Error compensation method
When position control is carried out by the "movement amount per pulse" set in
the QD75 parameters, an error sometimes occurs between the command
movement amount (L) and the actual movement amount (L').
That error is compensated in the QD75 by adjusting the values in "
pulses per rotation (Ap)", "
Pr.4
"
Unit magnification (Am)". (When " Pr.1 Unit setting" is "0: mm")
(1) Definition
The "error compensation amount" used to carry out the error compensation
is defined as follows.
Error compensation amount =
The QD75 "movement amount per pulse" is calculated with the following
equation.
Movement amount per pulse is "A", "
Pr.3
(Ap), "
magnification" is (Am).
A =
(2) Procedure
(a) Set the "command movement amount (L)", and carry out positioning.
(Set the "movement amount per pulse (A)" according to Section 5.2
"List of parameters".)
(b) After positioning, measure the "actual movement amount (L')".
(c) Calculate the "error compensation amount".
Error compensation amount =
(d) Calculate the post-compensation "
(Ap')", "
magnification (Am')" from the "post-compensation movement amount
per pulse (A')".
A =
=
=
(Adjust with Am' so that Al' and Ap' do not exceed the setting range.)
Pr.3
Movement amount per rotation (Al)", and
Designated movement amount (L)
Movement amount per rotation" is (Al), and "
Al
Am
Ap
Pr.3
Movement amount per rotation (Al')", and "
A
Error compensation amount
Al
L'
Am
Ap
L
Al'
Am'
Ap'
12 - 14
Actual movement amount (L')
Pr.2
No. of pulses per rotation" is
L'
L
Pr.2
No. of pulses per rotation
MELSEC-Q
Pr.2
No. of
Pr.4
Unit
Pr.4
Unit
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Troubleshooting
