Gain And Speed Adjustments; Gain Adjustment; Span Adjustment Graph - ABB AV3 Instruction Manual

CALIBRATION

GAIN AND SPEED ADJUSTMENTS

Gain Adjustment

GAIN AND SPEED ADJUSTMENTS
4 - 8
1 0 0
O U T PU T
PO S IT IO N
5 0
(0 TO 100 %
T R AV EL)
0
0
Figure 4-5. Span Adjustment Graph
This flexibility in span adjustment is useful when the device being
regulated is oversized, since the adjustment allows operation of
the actuator or cylinder through its useful motion for desired full
change in control signal pressure. It also is useful in matching the
signal versus position characteristics of the actuator or cylinder
with the characteristics of related power devices in the same con-
trol system.
Gain and speed adjustment information applies to both the Type
AV3 and Type AV4 positioners. This is the gain of the overall posi-
tioner. The factory installed gain hinge spring (0.010 inch) suits
most applications. This adjustment is not a mandatory part of cali-
bration.
Gain adjustment on the Type AV positioners is accomplished by
changing the gain hinge spring (item 7, Figures
connecting the beam assembly to the positioner housing. Pro-
vided with each positioner are two different gain hinge springs. If
actuator oscillation occurs, the overall positioner gain may be too
high. Positioner gain is related to the thickness of the gain hinge
spring. Gain decreases as the thickness of the gain hinge spring
increases. Refer to Table
5 0
IN P U T SIG N AL
(0 TO 100 % )
4-2 for hinge information.
1 0 0
T 00 77 6 A
9-3 through 9-6)