Flowserve Logix MD+ ValveSight - Manual (Page 88)

ValveSight™ Diagnostics DTM Manual for Logix MD+ Positioner with HART®
FCD- LGENSF0014-00
© Flowserve Corporation
88
Warnings and Alarms
Pilot Response
•
Definition: The pilot relay is sticking or slow to respond.
•
Implications: This affects the responsiveness, increases the chance of
limit cycling and excessive air consumption. The pilot relay is part of the
inner loop and consists of the driver module assembly with piezo (I-P
relay) which is coupled to the spool valve or poppet. The value of this
indicator corresponds with inner loop lag. Delayed response can be
caused by a partially clogged piezo or debris, oil, corrosion, or ice on
the spool, or low supply pressure.
•
Possible Solutions: Check response of the valve. If OK, adjust Pilot
Relay Response limits. Check supply pressure. Check the spool or
poppet for debris, oil, corrosion, ice on the spool. Clean or replace the
spool or poppet assembly. Replace the piezo or driver module
assembly. Maintain a clean, water-free air/gas supply.
Pilot Cycle
•
Definition: The pilot relay cycle limit set by the user has been
exceeded.
•
Implications: The pilot relay cycles indicate the activity level of the pilot
relay as it maintains a valve’s position. Excessive cycles can contribute
to a worn relay which can lead to high air consumption.
•
Possible Solutions: Inspect for high air consumption and signs of
wear.
Pilot Travel
•
Definition: The total accumulated pilot relay travel (% of full relay span)
set by the user has been exceeded.
•
Implications: The pilot relay travel indicates the activity level of the
relay as it maintains a valve’s position. Excessive travel can contribute
to a worn pilot relay which can lead to high air consumption.
•
Possible Solutions: Inspect for high air consumption and signs of
wear.