Speed Adjustment; Orifice Speed Control; Speed Control By Pilot Valve Stroke Adjustment; Gain Hinge Spring Characteristics - ABB AV3 Instruction Manual

Speed Adjustment

For information on changing the gain hinge spring, refer to
HINGE SPRING in Section 8.
Table 4-2. Gain Hinge Spring Characteristics
Part Number
2
5400264_1
5400264_2
NOTES:
1. To distinguish hinge type, the thickness is printed on the hinge (i.e.,
0.010, or 0.030).
2. Comes installed from the factory.
Normally speed adjustment is not required when calibrating a
positioner. Type AV positioners come from the factory adjusted for
maximum operating speed. However the speed of operation can
be reduced in two ways. Speed control orifices can be used to
slow positioner operation or a speed adjustment can be made
internal to the positioner to change operating speed.
When the system involves only a single actuator, a high position-
ing speed is usually an advantage. However, in a complex control
system, it is generally desirable to operate all power devices at the
same speed in order to avoid interaction between units and con-
sequently undesirable process conditions.

ORIFICE SPEED CONTROL

If it is necessary to reduce the speed of operation, 1.02-millimeter
(0.040-inch) speed control orifices (part number 5327327_1) are
available as an option from ABB. These orifices are installed
directly into the output ports (01 and 02) of the positioner and have
¼-NPT ports for connecting tubing from the actuator. If these ori-
fices are too small (causing the actuator to respond too slowly)
they may be drilled out to obtain desired speed control. Blank ori-
fices (part number 5327327_2) are also available.

SPEED CONTROL BY PILOT VALVE STROKE ADJUSTMENT

If it is necessary to reduce the speed of operation, a pilot valve
stroke adjustment can reduce the speed and does not require
additional hardware. This adjustment limits the pilot valve stroke.
The pilot valve stroke is measured by the movement (displace-
ment) of the pilot valve stem. Figure
stroke length which is also the maximum speed of operation and
Thickness
Gain
mm in.
0.25 0.010 High
0.76 0.030 Medium
4-6 shows the maximum
GAIN AND SPEED ADJUSTMENTS
CALIBRATION
GAIN
4 - 9