Flowserve 420 IOM - Manual (Page 23)

User Instructions - Logix® 420 Series Digital Positioners FCD LGENIM0106-06 12/13
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23
Split Range Example:
A split range is easily configured. For example, a 4 to 12 mA
signal can be set to correspond to a 0 to 100% stroke. When
the display shows “Set 0%”, set the command input current
to 4 mA. (The display will show a low Analog to Digital Count
(ADC) that corresponds to 4 mA.) Then press the
►ACCEPT/QUICK-CAL button to set the value. Press the
▼Down button to move to “Set 100%”. Set the command
input current to 12 mA. (The display will show a high ADC to
correspond to 12 mA.) Again press the
►ACCEPT/QUICK-
CAL button to set the value. Select the ◄Back Button to
exit.
Signal At Closed = 20mA Example:
If the desired signal at closed is 20 mA, first set the Signal at
Closed DIP switch to 20 mA. Then perform a stroke
calibration by pressing the
►ACCEPT/QUICK-CAL button for
more than 3 seconds. This registers the DIP switch settings.
Then, in the Command Input Calibration menu, when the
display shows “Set 0%” it is expecting the lowest current
value. Set the input curre
nt to 4 mA. For “Set 100%”, it is
looking for the highest current value. Set the input current to
20 mA. After accepting theses values, the positioner will
interpret the 20 mA input as 0% valve position and the 4 mA
input as 100%.
Calibration Dates lists the most recent date of each
calibration. The date is available only if the calibration was
performed using the DTM.
10.3.5 Configuration (Positioner Tuning)
The Configuration
– Positioner Tuning menu allows the user
to manually adjust individual tuning parameters. All tuning
parameters are automatically set to optimal values during
Quick-Cal. Typically a Quick-Cal is all that is needed for
positioner tuning. See section 8 STARTUP for more details.
CAUTION: Adjusting the tuning parameters will affect
the responsiveness of the valve and could cause rapid
changes to the valve position. Notify proper personnel that
the valve may stroke, and make sure the valve is properly
isolated before proceeding.
P-Gain, I-Gain and D-Gain are the proportional, integral, and
differential elements of the feedback algorithm. These gains
are different for the opening and closing directions because
typically responsiveness is different in each direction.
NOTE: Only those with specific training in PID tuning
algorithms should attempt to adjust the tuning by manually
changing the PID values.
Open Stroke Time is the fastest time it took the valve to
stroke from 0% to 100% during Quick-Cal. Increasing this
parameter will affect the responsiveness of the valve in the
opening direction.
Close Stroke Time is the fastest time it took the valve to
stroke from 100% to 0% during Quick-Cal. Increasing this
parameter will affect the responsiveness of the valve in the
closing direction.
Minimum Open Time and Minimum Close Time (Speed
Limits) are used to prevent the valve from moving too quickly.
This can be used when the process is sensitive to rapid flow
or pressure changes. This shows the time (in seconds) that
the positioner will allow the valve to travel a full stroke. This
speed limit applies to smaller movements of the valve too.
For example, if the Minimum Open Time were set to 20
seconds, and the command was changed from 40% to 50%,
the positioner would move the valve at a constant rate, taking
2 seconds to complete the move. If the Minimum Close Time
was set to 0, and the command was changed from 50% back
to 40%, the positioner would make the move as quickly as
possible.
The default values are 0 seconds, meaning the positioner will
move the valve as quickly as possible.
10.3.6 Configuration (Characterization)
The Configuration
– Characterization menu allows the user to
change the characterization of the command. This allows a
better match between the input command and the actual fluid
flow through the valve. This feature is typically used with
valves that have non-linear flow characteristics. The
positioner makes a correction by applying an adjustment to
the input command according to a characterization curve.
The table below shows the available characterization curve
options. Each point of the Custom curve can be adjusted
using the ValveSight DTM.
To view the characterization curve options, set the
Characterization switch “Other” before performing a Quick-
Cal. Otherwise, the only option available is
“Linear”. If a
Quick-Cal is not possible, use the ValveSight DTM to select
the curve.
►Configuration
►Positioner Tuning
►P-Gain Open
►I-Gain Open
►D-Gain Open
►P-Gain Close
►I-Gain Close
►D-Gain Close
►Open Stroke Time
►Close Stroke Time
►Minimum Open Time
►Minimum Close Time
►Configuration
►Characterization
►MaxFlo Linear
►MaxFlo Equal %
►Valdisk Linear
►Valdisk Equal %
►ShearStream Linear
►ShearStream Equal %
►Custom