Woodward 2301E-HT, Руководство по эксплуатации продукта

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Manual 35092 2301E-HT Hydro (Francis Turbines)
Woodward 23
Pond/Tail Level Control
The Pond/Tail Level Control mode can control the forebay level (pond level) or the tailbay level to a set
point by openin
g and closing the gates. Level Control can be enabled using the “Pond/Tail Level Control
Enable” discrete input or Modbus. The pond/tail level input signal must be valid for Level Control mode to
be enabled. If the level signal is lost, an alarm will indicate the failure, and the control will disable Level
Control.
The only difference between Pond and Tail Level control is that the gates will move in opposite directions
as a result of the Level Error. If the control is configured for Tail Level control and the level is greater than
the set point, the gates must close to reduce the error. However, if the control is configured for Pond
Level control and the level is greater than the set point, the gates must open to reduce the error.
If you are controlling the Pond Level (forebay level), be aware that
increasing your Pond Level set point results in decreasing the gate
position, and vice-versa. Thus, the Raise input will result in moving
the gates in the closing direction.
When Level Control is enabled, the Raise and Lower contact inputs control the Level Set Point. The Level
Set Point “Raise/Lower Rate” controls how fast the set point ramps up and down. The level set point can
also be adjusted using the Woodward Watch Window or Modbus.
When Level Control is enabled, there are two options. The control can be configured to maintain a preset
level set point, or it can be configured to “follow” actual level and gate position. If the application always
requires the same level set point when in Level Control, the control should be set up to maintain the
preset level set point. Each time the Level Control mode is enabled, the control will use the preset level
set point. The set point can still be adjusted using the Raise and Lower commands. If a bumpless transfer
is needed or desired when Level Control is enabled, the control should be set to “follow” actual level and
gate position. When Level Control is enabled, the gates will stay where they are at that time.
The level transducer range must also be entered into the 2301E-HT during the initial configuration. The
“Elevation at 4 mA” and the “Elevation at 20 mA” refer to the elevation of the water level when the level
transducer is generating 4 and 20 mA. These high and low limits become the limits of the Level set point,
and they are also used to calculate the Remote Reference for Level Control (if used). The elevations can
be in any unit of measurement, but the units must stay consistent for all other values relating to Pond/Tail
Level control (level feedback sign
al, level set point, and desired accuracy). The “Maximum Gate Position”
and “Minimum Gate Position” in Level Control mode must also be configured. This can prevent the unit
from motoring or from overloading in Level Control.
The Level Control algorithm is designed so that several units can be controlling pond/tail level together
without any communication between controls and without fighting each other. However, the consequence
of being able to do this is that the control does not integrate out all error between actual level and the
level reference. By design, the only gate position where there will not be any level error is the midpoint
between “Maximum Gate Position” and “Minimum Gate Position.” Therefore, the “Desired Control
Accuracy” must be configured. This desired control accuracy has the same units as the elevation levels
discussed above. If the desired control accuracy is 1 foot, the 2301E-HT will control the level, but there
may be some error (less than one foot) remaining during steady state.
Released