Servo Adjustments (Type Av4 Positioner) - ABB AV3 Instruction Manual

CALIBRATION

Servo Adjustments (Type AV4 Positioner)

WARNING
TROUBLESHOOTING CALIBRATION ADJUSTMENTS
4 - 14
The Type AV4 positioner servo comes from the factory completely
calibrated. The adjustments shown in the following procedures
should only be performed when required.
criterion for the adjustments.
The purpose of this procedure is to adjust the servo so that it pro-
duces a 20.7 to 103 kilopascals (three to 15 pounds per square
inch gage) pneumatic signal when pulsing the input. Use the fol-
lowing procedure to perform the check.
1. If electrical connections have not been made, refer to
TYPE AV POSITIONER
Type AV positioners are suitable for a maximum supply
pressure of 1034 kPa (150 psig). Do not exceed maximum
recommended final control element operating pressure.
1. Connect supply air (172 to 1034 kPa (25 to 150 psig)) to the S
port on the manifold (if equipped) or positioner. The minimum sup-
ply pressure must be 34.4 kPa (5.0 psig) above the operating
requirements of the actuator.
2. Apply the supply air to the positioner.
3. Connect a calibrated pressure gage (or some other accurate
pressure measuring device) to the I port. This allows you to moni-
tor the signal pressure during calibration.
4. Adjust the internal pressure to the minimum value (13.8 to
17.0 kPa (2.0 to 2.5 psig)). Do so by closing the lower contact
until the pressure stops decreasing.
a. If 13.8 to 17.0 kPa (2.0 to 2.5 psig) pressure is obtained,
proceed to Step 6.
b. If the desired pressure is not obtained, proceed to Step 5.
5. Loosen and back off the minimum locknut. With the lower
contact closed, rotate the minimum stop screw (clockwise to
increase) until a pressure of 13.8 to 17.0 kPa (2.0 to 2.5 psig) is
obtained. Verify that the hub screw is still in contact with the tip of
the minimum stop screw (Fig. 4-9). Tighten the minimum locknut
and check the pressure.
Section 6
in Section 3.
outlines the
WIRING