Start-Up
and
Adjustments
38
4.) Press
<P>
to
tum
to
the
SETUP
page.
5.) Move
the
cursor
to
Mode and select auto-tune mode by entering 4 followed by <ENTER>. The
terminal screen should appear as shown in Figure 5-10.
6.) Adjust Dist, Max
Vel
, and Step I if required. Note that the default values should provide
good
results for most systems. The Step I should be reduced if the torque will exceed machine
specifications.
7.) Tum
to
the STATUS page
by
pressing
<P>
to
insure that FAC and RAC are
not
enabled then
return
to
the SETUP page
by
pressing < P > again. ·
8.) Enable the BRU-Series drive
to
start the auto-tune process which will cause the
motor
to
move in a
back-and-forth motion.
9.) The computed values for P GAIN and I
GAIN
will appear on the screen after 5 seconds. The BRU-
Series drive signals completion by commanding 0 current
to
the motor and se.nding a "beep"
to
the
user terminal.
1 0.) Move
the
cursor
to
Mode and select velocity mode
by
entering 1 followed
by
<ENTER>.
11
.) Press < S > if
the
present tuning is
to
be saved into the personality module. Saving
the
parameters
requires that the write protect jumper J10
is
set
to
the appropriate position (refer
to
Figure 5-2).
Attempts
to
move J10 with power applied
to
the servo drive may result in damaging the
personality module.
5.3.2 Using Tune Mode
The tune mode is designed
to
optimally tune the BRU-Series drive. For most applications, the default
tuning values
or
the results
of
auto-tune should provide adequate tuning. For applications with particular
requirements, tune mode can be used
to
fine tune the system. A suggested tuning procedure
for
velocity
mode operation is discussed below. This procedure assumes that the system, including
the
machine
the
motor is connected to, can tolerate small-signal step velocity changes. There is essentially no tuning
required
for
torque mode; P GAIN, I GAIN, and D
GAIN
have no effect in torque mode.
The tuning
of
the velocity regulator is accomplished
by
changing the variables P GAIN, I GAIN, and D
GAIN. The P GAIN is the proportional gain
of
the velocity regulator. In general, increasing P GAIN reduces
the
time required
to
reach the commanded velocity. The I GAIN is the integral gain
of
the velocity
regulator. Integration in the velocity regulator forces the motor velocity
to
precisely follow the commanded
velocity with no error under steady state conditions (no changes in velocity command
or
load). Increasing
I GAIN increases the stiffness,
or
the ability
to
reject load disturbances. Increasi
ng
I GAIN also, however,
increases the amount
of
velocity overshoot when responding
to
a step change in velocity. Too much I
GAIN can cause the system
to
go
unstable. The D GAIN is the damping gain. It is used
to
reduce the
amount
of
overshoot caused by the I GAIN term. It can also be used
to
minimize torsional resonance
between the
motor
and load in some systems. A block diagram
of
the velocity regulator is shown in Figure
5-11
.
BRU-200/BRU-500 Brushless Drives Instructi
on
Manual
(
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