System philosophy
HARDWARE REFERENCE MANUAL
29
Revi
si
on 3.0
Integral gain can cause overshoot and so is usually used only
on systems working at constant speed or with slow
accelerations. The integral gain axis parameter is called
I_GAIN
.
•
Derivative gain
The derivative gain
K
d
produces an output
O
d
that is
proportional to the change in the Following Error
E
and speeds
up the response to changes in error while maintaining the same
relative stability.
O
d
= K
d
·
Δ
E
Derivative gain may create a smoother response. High values
may lead to oscillation. The derivative gain axis parameter is
called
D_GAIN
.
•
Output speed gain
The output speed gain
K
ov
produces an output
O
ov
that is
proportional to the change in the measured position
P
m
and
increases system damping.
O
ov
= K
ov
·
Δ
P
m
The output speed gain can be useful for smoothing motions but
will generate high Following Errors. The output speed gain axis
parameter is called
OV_GAIN
.
•
Speed feed forward gain
The speed feedforward gain
K
vff
produces an output
O
vff
that is
proportional to the change in demand position
P
d
and
minimizes the Following Error at high speed.
O
vff
= K
vff
·
Δ
P
d
The parameter can be set to minimise the Following Error at a
constant machine speed after other gains have been set. The
speed feed forward gain axis parameter is called
VFF_GAIN
.
The default settings are given in the table along with the resulting
profiles. Fractional values are allowed for gain settings.
/i
Gain
Default value
Proportional gain
0.1
Integral gain
0.0
I51E-EN-03.book Seite 29 Donnerstag, 28. Juni 2007 1:05 13