SMC Networks IP8001 Series Operation Manual page 80

Error
Low sensing
Hunting problem
Large air consumption
Automatic calibration
is unavailable
Possible cause
- Input current resolution is faulty.
-Actuator's sliding resistance is
large.
-Dead band value is high.
-Operation takes time due to the
actuator's large capacity.
-Others.
-Actuator is uncalibrated.
-PID constant after calibration is
improper due to use of a special
valve.
-There is play in the mounting of
the feedback lever and actuator.
-The input current itself is unstable.
-Rotation resistance of the actuator
is significant due to ground and
piston packing.
-Air is leaking from the piping.
-Air is leaking from the positioner.
(due to a seating failure of the pilot
valve. )
-Others.
-The angle of the feedback lever is
in excess of –30/+30 degrees on
both ends of the actuator.
- The angle of the feedback lever
is less than 10 degree or 30
degree or larger
-Others.
79
Countermeasure
- Check the input current system.
-Reduce the sliding resistance to as
little as possible.
-Operate only the actuator and check
the stick-slip movement. If this
movement cannot be recovered, it's
beyond the capacity
positioner.
-Change the dead band with the
parameter mode.
-Wait until the actuator fills with air.
-Contact SMC representatives.
-Calibrate the actuator with the
parameter mode.
-Change the PID constant with the
parameter mode.
-Eliminate the play and properly
mount them.
-Check the input current system.
-Ground properly.
-Reduce rotation resistance as much
as possible.
-Check the piping, and stop
the leakage.
-Replace the pilot valve unit.
-Contact SMC representatives.
-Refer to "2. Check the angle of the
" ■ Initial
feedback lever" in
Adjustment", and securely adjust the
angle to –30/+30degrees or less.
-The standard positioner stroke is
from 10 to 30 degrees.
within 10 to 30 degrees.
-Contact SMC representatives.
Reference
page
5
-
of this
50
-
-
23 to 25
56 to 58
10, 11
14,15
76-⑫
-
75-⑧
75-⑦
-
21,22
Use it 5
-
No.IP8S-OM00009