Span Adjustment (Av3); Av4 Calibration; Cam Roller Alignment - ABB AV3 Instruction Manual

CALIBRATION
C A M
C A M RO LL ER
C A M F O LLO W E R AR M
T 00 7 71 A
Figure 4-2. Cam Roller Alignment

SPAN ADJUSTMENT (AV3)

Setting the span normally requires the alignment of the 100 per-
cent radial line of the cam with the center of the cam roller. Use
the following steps to adjust the span.
1. Apply 20 mA to the positioner. The actuator should move to its
full open position.
⁄
2. Loosen the span adjustment screw (Fig. 4-1) using a -inch
5 32
Allen wrench.
3. Slide the span adjustment assembly (Fig. 4-1) in the appropri-
ate direction until the actuator moves to align the 100% radial line
with the center of the cam roller (toward pilot valve increases span
of actuator).
4. Tighten the span adjustment screw.

AV4 Calibration

The Type AV4 positioner uses voltage pulses from a controller to
produce a proportional internal signal of 20 to 103 kilopascals
(three to 15 pounds per square inch). Pulses to either the raise or
lower terminal moves the actuator and subsequently the posi-
tioner cam shaft. When the pulse is removed the positioner holds
its position just prior to the end of the pulse. The positioner does
GENERAL CALIBRATION
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