GE FVP110 Maintenance Manual page 195

Troubleshooting Valve Control
Problem
The deviation between the
setpoint and readback
signal remains.
The valve oscillates
cyclically (limit cycle).
Table 57 Troubleshooting Valve Control (Continued)
Presumed Cause
The tight-shut or full-open
action is active.
The travel calibration has not
been performed correctly.
The friction of grand packing is
large.
The dead band of integral
action is too little.
There's air leak from the pipe
of output pressure, or
feedback lever is not correctly
attached.
Remedy
Check the values of
FINAL_VALUE_CUTOFF_
HI and
FINAL_VALUE_CUTOFF_
LO.
Write 2 to
AUTO_TUNE_EXEC to
perform 0 &100% point
adjustment.
1) Write 4 or 3 to
AUTO_TUNE_EXEC to
redo auto tuning.
2) Use the actuator of
proper size.
Write 4 or 3 to
AUTO_TUNE_EXEC to
redo auto tuning. Or,
increase the
SERVO_DEADBAND
setting until the valve
stops oscillating.
Check the piping and
attachment of the lever,
and write 4 or 3 to
AUTO_TUNE_EXEC to
redo autotuning.
179
Troubleshooting
See Section
❑
"Tight-shut
and Full-open
Actions" on
page 125
❑
"Function
Block Parame-
ters" on
page 183
"Carrying out
Tuning" on
page 61
"Carrying out
Tuning" on
page 61
❑ "Carrying out
Tuning" on
page 61
❑ "Control
Parameters"
on page 132
❑ "Function
Block Parame-
ters" on
page 183
❑ "Manual Tun-
ing Guideline"
on page 253
❑
"Installing the
FVP110 on the
Actuator" on
page 35
❑
"Carrying out
Tuning" on
page 61