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