Specifications

RTS 2nd Generation SERVO AMPLIFIER
53
PVD 3487 GB 03/2004
7.2 Complete speed loop adjustment
Systematically applicable when J charge ≥ 10 J motors
Caution As servo amplifiers are factory set based on
parametersprovided by the customer, this setting does
not usuallyrequire adjustment.
Before adjusting the speed loop, all the adjustable
parameters must be fixed (current limits, speed scale
setting, speed limits). Adjusting the speed scale setting
alters loop gain and means readjustments are required.
Equipment required
- Storage oscilloscope (digital if possible), easy to trip.
- Manual speed reference generator (battery box) or low
frequency generator with series capacitor to produce
zero mean speed (out and return about a position).
- Decade box for capacitor and resistor adjustment.
Reference battery box, with oscillator for automatic
control is available as an option.
Method
FIG 1
Adjust the gain potentiometer to the centre (so gain may
be varied up or down after adjustment).
Fit a large integration capacitor C101 - 10µF or strap.
Adjust proportional gain starting by R101 = 10 kΩ.
Increase R101 until 10% overshoot on speed reference
increment. Always use small speed reference increments
(e.g. ± 100 rpm or less) so the system remains linear. For
large increments, current limitation (= torque limitation)
masks the real situation and reduces overshoot.
The adjustment obtained with high speed increments
would be incorrect.
In many cases, it is not possible to increase gain to
produce overshoot especially for high inertia systems.
< 100 Hz
a
b
c
Temps
Vitesse prise entre
mesure N et 0V ana. dépassement : + 10 %
-
+
batterie
9 V
INVERSEUR
10K
Réf. E -
Réf. E +
15
14
Servoamplificateur
Gain
R108
R101
C103
C101
FIG 1 : a, b, c - graphs obtained with
increasing R101 values
Speed amp
INVERTER
10 K
1-5
Ref. E
1
-
Speed recorded
between N measurement
and 0 V analo
g
ue
overshoot : +10%
9 V
battery
Ref. E
1
+
1-
4
Time