Flowserve Logix 520MD+ DD - Manual (Page 16)

DD User Manual - Logix® 520MD+ Series Digital Positioner FCD-LGENSF0013-01
© Flowserve Corporation
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7.3.4 Soft Limits & Shutoff
Set Soft Limits that stop the valve from traveling beyond a set
point. Set Shutoff limits that cause full pressure to close or
open the valve.
7.3.4.1 Soft Stop High
Set the maximum valve position the final command will allow,
regardless of the analog or digital input command. This is
similar to placing a physical block on the valve stem to limit
the amount the valve can open.
7.3.4.2 Soft Stop Low
Set the minimum valve position the final command will allow,
regardless of the analog or digital input command. This is
similar to placing a physical block on the valve stem to limit
the amount the valve can close.
7.3.4.3 Tight Shutoff Upper
Set the upper command limit that will trigger the positioner to
apply full supply pressure in the open direction. For
example, after setting the Tight Shutoff Upper to 95%, if the
positioner receives any input command greater than 95%, full
supply pressure will be applied to open the valve.
7.3.4.4 Tight Shutoff Lower
Set the lower command limit that will trigger the positioner to
apply full supply pressure in the close direction. For
example, after setting the Tight Shutoff Upper to 5%, if the
positioner receives any input command less than 5%, full
supply pressure will be applied to close the valve.
7.3.4.5 Tight Shutoff Hysteresis
Enter the amount the command must backtrack in order for
the positioner to return to regular control. For example, it the
Tight Shutoff Upper is set to 90%, and Tight Shutoff
Hysteresis is set at 2%. The command must return from
90% to 88% in order for the positioner to control normally.
This is to prevent an oscillation in and out of Tight Shutoff
mode.
7.4 Alerts / Alarms Config
View and set alarm and alert limits.
7.4.1 Position
View and set alarm and alert limits regarding position.
7.4.1.1 Position High Alert
Set the upper limit at which an alert will be sounded. The
valve will be allowed to continue travel beyond this point.
7.4.1.2 Position Low Alert
Set the lower limit at which an alert will be sounded. The
valve will be allowed to continue travel beyond this point.
7.4.1.3 Position Deviation Dead band
Set the amount of allowable deviation before sounding the
Position Deviation alarm. The deviation must remain for the
time set in the Position Deviation Time parameter.
7.4.1.4 Position Deviation Time
Set the amount of allowable time before sounding the
Position Deviation alarm. The deviation must be outside of
the deviation limit set in the Position Deviation Dead Band
parameter.
7.4.2 Pneumatic Leak
View and set pneumatic leak limits.
7.4.2.1 Leak Pneumatic
View the amount of pneumatic leak beyond normal air
consumption. This feature requires Pro diagnostics.
7.4.2.2 Leak High Start Limit
Set the pneumatic leak limit at which a warning will appear.
7.4.2.3 Leak High End Limit
Set the pneumatic leak limit at which a warning will show full
severity.
7.4.2.4 Leak Percent Warning
View the severity of the pneumatic leak warning based on the
Start and End limits.
7.4.3 Friction
View and set friction limits. This feature requires Pro
diagnostics.
7.4.3.1 Friction
View the friction of the valve and actuator assembly.
7.4.3.2 Nominal Friction
View the last saved friction value.
7.4.3.3 Friction Hi Start Limit
Set the high friction limit at which a warning will appear.
7.4.3.4 Friction Hi End Limit
Set the high friction limit at which a warning will show full
severity.
7.4.3.5 Friction Low Start Limit
Set the low friction limit at which a warning will appear.
7.4.3.6 Friction Low End Limit
Set the low friction limit at which a warning will show full
severity.
7.4.3.7 Friction Hi Percent Warning
View the severity of the high friction warning based on the
Start and End limits.
7.4.3.8 Friction Low Percent Warning
View the severity of the low friction warning based on the
Start and End limits.
7.4.3.9 Force Up at 15 Percent
View the force required to move the valve up at 15% position.
7.4.3.10 Force Down at 15 Percent