GLENTEK Inc. 208 Standard Street, El Segundo, California 90245, U.S.A. (310) 322-3026
23
Tach Voltage
RPM
Not enough Tach Under Damped Over Damped
Too much Tach Not enough Tach
or not enough
Bandwidth
Figure 6.4
6.5 CONNECTING AMPLIFIER TO A DIGITAL POSITION LOOP:
1. Before connecting the amplifier to a digital position loop, be sure the adjustments of section 6.4 have been
made. Start out with Loop-Gain potentiometer, R18, fully CCW and activate the digital position loop. Slowly
turn Loop-Gain potentiometer CW. If servo runs away, immediately adjust Loop Gain fully CCW and turn
power OFF.
It is possible, at this time, that the digital loop is reverse phased. An example of this would be if a positive
voltage from the velocity DAC (digital to analog converter) required the motor to turn CW. However, it
turned CCW instead causing the encoder feedback signal to count up instead of down. This would cause a
run away condition.
If you are out of phase as described, be sure power is OFF and reverse the motor leads at the amplifier.
This will cause the motor to rotate in the opposite direction than it did before, properly phasing the digital
loop.
2. With the Digital Loop operating, turn the Loop-Gain potentiometer, R18, fully CW and command a small
move. Slowly increase or decrease the Signal-Gain potentiometer, R12 or R13, until the servo is operating
as required. It should be noted here that too much Signal Gain can cause instability (oscillation). Do not
stay in this oscillating condition long, as it may result in system mechanical or electrical damage. Be sure
when all signal adjustments are made that the Balance is re-checked and adjusted for zero rotation for
zero signal input.
It should also be noted here that the GA45xxPR2 is designed to operate with many different systems and
if, after reading this manual, you have further questions, do not hesitate to call a Glentek applications engi-
neer.
CHAPTER SIX: START UP AND ADJUSTMENT PROCEDURE
