Zero Adjustment (Av3); Type Av Calibration Adjustment Locations - ABB AV3 Instruction Manual

CALIBRATION
PILOT VALV E
O PT IO N AL
M A N IF O L D
SPA N A D JU S T M EN T A S S EM B LY
SPA N A D JU S T M EN T S C R EW
Figure 4-1. Type AV Calibration Adjustment Locations
GENERAL CALIBRATION
4 - 2

ZERO ADJUSTMENT (AV3)

Setting the zero requires the alignment of the zero percent radial
line of the cam with the center of the cam roller. Use the following
steps to adjust the zero.
1. Apply a 4 mA input signal to the positioner. The actuator
should be in the closed position.
2. Loosen the zero adjustment set screw (Fig. 4-1) with a
⁄
-inch Allen wrench.
3 32
1 2 3 4
T ER M IN AL BLO C K T B1
C A BLE C LA M P
3. Turn the zero adjustment nut (clockwise moves actuator down
range) appropriately until the 0% radial line on the cam intersects
with the center of the cam roller (Fig. 4-2).
NOTE: This adjustment may be biased, i.e. turning the zero nut
slightly counterclockwise to make sure a valve or damper is
firmly seated at the minimum input signal.
4. Tighten the zero adjustment set screw.
5
Z ER O A D JU ST M E N T N U T
Z ER O AD JU ST M E N T SE T SC R E W
SE RVO
AS SE M B LY
C O N D U IT
H O LE
T 02 0 02 A