ABB AV2123000 Positioner User Manual

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 supply
pressure, input and output connections, and mechanical
adjustments before removing it from service.
WARNING
Disconnect the supply signal source or remove the equipment
from the process before servicing. Failure to do so
can cause unexpected movement posing a risk of bodily
injury.
Oscillation of
actuator
Table 6-1. Positioner Errors
Error Probably Cause Corrective Action
Actuator at one end
of stroke and does
not respond to input
change
Drive arm not
securely attached to
actuator.
Pneumatic signal
leak.
Pilot valve sticking.
Gain too high.
Air lines in wrong
ports.
Incorrect cam
installed for application.
Pneumatic signal
leak.
Mechanical calibration
shift.
I/P converter not
functioning.
Tighten or correct linkage as necessary.
Check for leaks in connectors or fittings.
Remove pilot valve and clean or replace. Refer to Pilot Valve
Assembly in Section 8.
Change gain hinge spring to greater thickness. Refer to Gain
Hinge Spring in Section 8.
Check air line connections (Figs. 3-10, 3-11, 3-12, 3-13 and
3-14).
Determine application (reverse or direct acting) and check for
correct cam (Figs. 3-10, 3-11, 3-12, 3-13 and 3-14).
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).
Make sure the linkage between positioner and actuator is tight
and has no backlash.
Check I/P converter calibration (refer to TROUBLESHOOT-
ING CALIBRATION ADJUSTMENTS in Section 4).
INTRODUCTION
6 - 1