Azbil ACN Series, Руководство пользователя

Страница: 91 / 100

13-1
Chapter 13. Troubleshooting
This Chapter covers problem, causes and remedial actions regarding most probable types of
troubles. Parts may be required to be replaced depending on the type of. For further problem,
please contact an Azbil Corporation agent for repair.
Table 13-1. Troubleshooting
Problem Cause and Remedial Action
Unstable valve
operation
• Valve position hunting
occurs when almost
fully closed.
• Air supply pressure is
unstable.
• Signal pressure is
unstable.
• Valve position hunting
occurs even when
signal pressure is stable
• Cv value is too large.
• Reduce Cv value
• For a single seat valve, the valve is installed in the reverse
flow direction.
• Large air consuming equipment is hooked up to the same air
supply line.
• Check that the air supply capacity, piping capacity and
restriction capacity are appropriate.
• Supply air pressure regulator is inadequate or not operating
properly.
• Controller is not properly tuned.
• Property tune the controller (properly set the proportional
band and other parameters).
• Check that the controller output does not change
abnormally.
• Hunting of output of positioner itself.
• Check and repair or replace the positioner.
• Being affected by pressure change of process fluid as power
of the actuator is insufficient. Replace the actuator with a
larger one.
Vibration of valve
• Valve vibrates
(generate noise) at any
position of valve plug
• Valve vibrates
(generate noise) only
when valve plug is set
at a certain position.
• Piping is vibrating.
• Securely fix the piping.
• Check for other sources of vibration.
• Worn valve plug or guides.
• Check for change in process fluid flow conditions.
• (Change in restriction orifice, Cv value, etc.)
• Check for change in plug configuration (change in flow
control characteristics.)