Manual 35018V1
505XT Digital Control System for Steam Turbines
Woodward
138
GEN BREAKER OPEN EXT/ADM DISABLE ?
dflt= YES (Yes/No)
Select YES if the Ext/Adm pressure control will be disabled when the gen tie breaker opens. If NO is
selected, then Ext/Adm pressure control will not be disabled when the gen breaker is opened.
NOTE:
(GEN Breaker Open Always Inhibits Ext/Adm control)
GENERATOR BREAKER OPEN EXT/ADM INHIBIT
dflt= YES (Yes/No)
Select YES if the Ext/Adm pressure control will be inhibited when the generator breaker opens. If NO
is selected, then Ext/Adm pressure control will not be inhibited when the generator breaker is open
and the control will control on the Ratio Limiter.
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 Ext/Adm pressure 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)
ALLOW USE OF FULL DECOUPLED MODE ?
dflt= NO (Yes/No)
Set to YES to allow access to this selection in Service mode while the turbine is in operation.
Exhaust Control Menu
USE EXHAUST PRESSURE/FLOW CONTROL?
dflt= NO (Yes/No)
Select YES to configure the exhaust pressure control function. Select NO if this function is not used.
LOST INPUT SHUTDOWN?
dflt= NO (Yes/No)
Select YES if a shutdown command is to be given when the exhaust pressure input fails. If NO, then
no shutdown command will be given when the exhaust pressure input fails, only an alarm. If exhaust
pressure is used as a limiter (“USE AS CONTROLLER” = NO, see below) and it is limiting the valve
demand at the time of the input failure, then selecting NO will cause the valve limiter to step to the
valve demand at the time of the failure to ensure that the limiting condition is not exceeded until the
operator has time to take action.
INVERTED?
dflt= NO (Yes/No)
Select YES if the exhaust pressure 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 exhaust pressure control.
MIN SETPOINT (UNITS)
dflt= 0.0 (-20000, 20000)
Set the min EXHAUST set point. This value is the minimum set point value that the exhaust pressure
set point can be decreased/lowered to (lower limit of EXHAUST set point).
MAX SETPOINT (UNITS)
dflt= 100 (-20000, 20000)
Set the max EXHAUST set point. This value is the maximum set point value that the exhaust
pressure set point can be increased/raised to (upper limit of EXHAUST set point).
(Must be greater than the ‘Min Exhaust Setpt’ Setting)
SETPOINT RATE (UNITS
/s
)
dflt= 5.0 (0.01, 1000)
Set the EXHAUST set point rate. This value is the rate (in units per second) at which EXHAUST set
point moves when adjusted.
USE AS CONTROLLER?
dflt= NO
Exhaust pressure is only available as a controller on Ext/Adm turbines, it can be used as a limiter on
single valve turbines.
SETPT INITIAL VALUE (UNITS)
dflt= 0.0 (-20000, 20000)
Set the set point initialization value. When not using the Exhaust Enable function, this is the value
that the exhaust pressure set point initializes to upon power- up or exiting the Configuration mode.
(Must be less than or equal to the ‘Max Exhaust 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 EXHAUST PID proportional gain value. This value is used to set inlet pressure control
response. This value can be changed in the Run Mode while the turbine is operating. If unknown, a
recommended starting value is 1%.