ABB AV1, Operating Instructions Manual

Page: 55 / 126

INTRODUCTION
6 - 1
SECTION 6 - TROUBLESHOOTING
INTRODUCTION
This section provides information about the Type AV positioner
when operating difficulties are encountered. A table listing errors,
probably causes and corrective actions allows the operator to
troubleshoot a problem pertaining to the positioner.
If a problem occurs and is traced to the positioner, check the sup-
ply pressure, input and output connections, and mechanical
adjustments before removing it from service.
WARNING
Disconnect the supply signal source or remove the equip-
ment from the process before servicing. Failure to do so
can cause unexpected movement posing a risk of bodily
injury.
Table 6-1. Positioner Errors
Error Probably Cause Corrective Action
Oscillation of
actuator Drive arm not
securely attached to
actuator. Tighten or correct linkage as necessary.
Pneumatic signal
leak. Check for leaks in connectors or fittings.
Pilot valve sticking. Remove pilot valve and clean or replace. Refer to Pilot Valve
Assembly in Section 8 .
Gain too high. Change gain hinge spring to greater thickness. Refer to Gain
Hinge Spring in Section 8 .
Actuator at one end
of stroke and does
not respond to input
change Air lines in wrong
ports. Check air line connections (Figs. 3-10 , 3-11 , 3-12 , 3-13 and
3-14 ).
Incorrect cam
installed for applica-
tion. Determine application (reverse or direct acting) and check for
correct cam (Figs.
3-10 , 3-11 , 3-12 , 3-13 and 3-14 ).
Pneumatic signal
leak. AV1: Check input signal connection for leaks at I port.
AV2: Check signal at I port. If pressure is between 20.7 and
103.4 kPa (3.0 and 15.0 psig) and responds to input signal
change then problem exists elsewhere.
If pressure is not between 20.7 and 103.4 kPa (3.0 and
15.0 psig) or does not respond to input change, check for
leaks inside positioner and check I/P converter calibration
(refer to
TROUBLESHOOTING CALIBRATION ADJUST-
MENTS in Section 4 ).
Mechanical calibra-
tion shift. Make sure the linkage between positioner and actuator is tight
and has no backlash.
I/P converter not
functioning. Check I/P converter calibration (refer to TROUBLESHOOT-
ING CALIBRATION ADJUSTMENTS in Section 4 ).