47
Logix
®
520MD+ and 510+ Digital Positioners FCD LGENIM0105-15-AQ – 05/16
flowserve.com
10.3.8 Configuration (Soft Limits and Shutoff)
.
Configuration
.
Soft Limits & Shutoff
.
High Soft Limit
.
Low Soft Limit
.
Upper Position Shutoff
.
Lower Position Shutoff
Soft Limits allows the user to limit the movement of the valve. Shutoff
allows the user to tightly shut the valve with all available force.
High Soft Limit and Low Soft Limit - This feature is used to simulate
physical blocks on the valve that restrict movement past a set point.
Once the Soft Limit is set, the positioner will not attempt to move the
valve position (final command) beyond the set point, regardless of the
analog or digital command input signal.
a
CAUTION:
Changing the Soft Limits may limit the movement of the
valve. The valve may not shut or open fully.
NOTE:
Removing power to below 3.6 mA will still cause the valve
to move to the de-energized state regardless of the Soft Limits.
Upper Position Shutoff and Lower Position Shutoff - This feature, (also
called Minimum Position Cutoff or MPC) is used to tightly close or open
the valve. It is used when a tight seal is needed or when debris or fric-
tion may otherwise interfere with complete closure. When the valve is
commanded past the Shutoff points, the pilot relay will direct full supply
pressure to the appropriate port, applying all available force to close (or
open) the valve. The Shutoff points apply to the Final Command.
a
CAUTION:
Changing the Shutoff limits may cause the valve to fully
open or fully close after the command passes a set limit.
Though Shutoff and Soft Limit features should not be used together, if
both are set, the greater of the two settings will take precedence at the
closed end; and the lesser of the two settings will take precedence at the
open end.
10.3.9 Configuration (Set Time and Date)
.
Configuration
.
Set Date & Time
1
1 Not available with 510+
The positioner has an internal clock. The clock allows time and date
information to be stored with alarms and other events. The clock does
not account for daylight savings.
Set Time and Date – Use the
.
Up and
.
Down buttons to set the time
and date. The format of the time and date is displayed above the input
fields.
10.3.10 Configuration (User Preferences)
.
Configuration
.
User Preferences
.
All Units
.
Pressure Units1
.
Force Units1
.
Temperature Units
.
Air Flow Units1
.
Actuator Area Units1
.
Date Format1
.
Number Format
.
LCD Orientation
1 Not available with 510+
The User Preferences menu allows the user to format how information
is displayed.
The following table shows the available options. By default the posi-
tioner is set to show information in International System (SI) units. To
change all units to North American (English), make the selection under
All Units. Each selection can also be changed individually.
Table 20: User Preference Options
Units/Format
International
System (SI)
(Default)
North Ameri-
can (English)
Other Options
All Units
SI
North Amer-
ican
-
Pressure
bar
PSI
kg/cm2,
kPa
Force
N
lbf
kg
Temperature
degrees C
degrees F
-
Air Flow
slph
scfm
slpm,
Nm3/hr
Actuator Area
cm2
in2
-
Date Format
Day.Mon.Year
Mon/Day/Year
-
Number
Comma
Decimal Point
-
LCD Orientation – Use this selection to turn the turn the display
upside down (180 degrees). Use this feature when the positioner is
mounted upside down.
