Manual 35018V1
505XT Digital Control System for Steam Turbines
Woodward
134
PROCESS SIGNAL
dflt= Auxiliary Input
Select which input the control should use. The input selected here should be configured as an
analog input, which is used as the process value for this controller.
INVERTED?
dflt= NO (Yes/No)
Select YES if the auxiliary control will be reverse acting. If NO, then the control will be forward acting.
Typically this will be set to NO, the only time the input would be inverted is if the valve needs to open
when the input exceeds the set point. An example where the invert would be YES is for turbine inlet
pressure control.
MINIMUM SETPOINT (UNITS)
dflt= 0.0 (-20000, 20000)
Set the min AUX set point. This value is the minimum set point value that the auxiliary set point can
be decreased/lowered to (lower limit of AUX set point).
MAXIMUM SETPOINT (UNITS)
dflt= 100 (-20000, 20000)
Set the max AUX set point. This value is the maximum set point value that the auxiliary set point can
be increased/raised to (upper limit of AUX set point).
(Must be greater than the ‘Min Aux Setpt’ Setting)
SETPOINT RATE (UNITS
/s
)
dflt= 5.0 (0.01, 1000)
Set the AUX set point rate. This value is the rate (in units per second) at which AUX set point moves
when adjusted.
USE AS CONTROLLER?
dflt= NO (Yes/No)
Select YES if using the Auxiliary control enable/disable feature. If YES, Aux will require an enable
command to enable Aux control. If NO, then the Auxiliary function will be enabled constantly and will
act as a controlling limiter. An example of using Aux as a limiter is using Aux to limit the maximum
KW load that the unit carries. The Aux PID is not normally in control of the valve output. But if the
Aux (KW) input exceeds the set point, the Aux PID controller would decrease and take control of the
valve until the KW level decreases below the maximum kW(Aux) setting. Alternatively, if the Aux
enable is used, the Aux set point tracks the Aux input. When enabled, the Aux PID takes control of
the valve and the speed set point tracks the speed/load of the unit for bumpless transfer between
modes.
SETPT INITIAL VALUE (UNITS)
dflt= 0.0 (-20000, 20000)
Set the set point initialization value. When not using the Aux Enable function, this is the value that
the auxiliary set point initializes to upon power- up or exiting the Configuration mode.
(Must be less than or equal to the ‘Max Aux Set Point’ Setting)
DROOP (%)
dflt= 0.0 (0.0, 100)
Enter the droop percentage. If required, typically set between 4–6%.
PID PROPORTIONAL GAIN (%)
dflt= 1.0 (0.0, 100)
Enter the AUX PID proportional gain value. This value is used to set auxiliary control response. This
value can be changed in the Run Mode while the turbine is operating. If unknown, a recommended
starting value is 1%.
PID INTEGRAL GAIN (%)
dflt= 0.3 (0.001, 50)
Enter the AUX PID integral gain value. This value is used to set auxiliary control response. This
value can be changed in the Run Mode while the turbine is operating. If unknown, a recommended
starting value is 3%.
PID DERIVATIVE RATIO (%)
dflt= 100 (0.01, 100)
Enter the AUX PID derivative ratio. This value is used to set auxiliary control response. This value
can be changed in the Service Mode while the turbine is operating. If unknown, a recommended
starting value is 100%.
TIEBRKR OPEN AUX DSBL ?
dflt= YES (Yes/No)
Select YES if the auxiliary control will be disabled when the utility tie breaker opens. If NO is
selected, then auxiliary control will not be disabled when the utility tie breaker is opened.
GENBRKR OPEN AUX DSBL ?
dflt= YES (Yes/No)
Select YES if the auxiliary control will be disabled when the generator breaker opens. If NO is
selected, then auxiliary control will not be disabled when the generator breaker is opened.
USE REMOTE SETPOINT ?
dflt= NO (Yes/No)
Set to YES to allow the set point to be adjusted from an analog input.
(Must program a ‘remote auxiliary set point’ analog input)
REMOTE MAX RATE (UNITS
/s
)
dflt= 5.0 (0.1, 1000)
Enter the maximum rate at which the remote input will move the remote set point.
UNITS OF MEASURE
(Configured with Analog Inputs)
DECIMALS DISPLAYED
(Configured with Analog Inputs)