Appendix E Falcon Lead Lag
E-59
If so then:
If the boiler's SlaveState is set to Available.
If any slave boiler is firing
then StagerState = Active
Otherwise
StagerState = Idle
STAGERSTATE = ACTIVE
During this state the stager is ready to manage add-stage and drop-stage requests.
If AddStageRequest is true
The Stager ask the Sequencer for an available slave.
When an available slave is found the stager repeats the above steps to bring this stage to Active.
If DropStageRequest is true and more than 1 slave burner is firing, the stager:
Invokes SetRecovering for the stage identified by DropStageRequest. This will turn the stage off and put it into
the recovering state until it has finished its postpurge (if any).
Resets and starts its StagerTimer, sets StagerTimeLimit to Drop-stage interstage delay, changes the Stager-
State to InterstageDelay, invokes an action to reset the Add/Drop detection timers.
When the Interstage time has elapsed, the Stager can execute an AddStage or DropStage request.
Add Stage Methods
Various methods can be used to determine when a new stage should be added. The internal algorithms that generate
AddStageRequests are called Add-stage methods.
All methods work by observing various criteria such as the Firing stages, the commanded rate, or setpoint error.
Adding Stages Parameters:
ADD-STAGE DETECTION TIME1: MM:SS
This provides time thresholds.
In the descriptions below, the relevant parameter is referred to as Add-Stage detection timeN.
Add-Stage method1:
Disable,
Error threshold,
Rate threshold,
dError/dt and threshold,
dRate/dt and threshold }
In the descriptions below, the relevant AddStageDetectTimer is referred to as
AddStageDetectTimerN.
ADD-STAGE ERROR THRESHOLD: DEGREES
This provides the error threshold as defined by the methods below.
ADD-STAGE RATE OFFSET: -100% TO +100%
This provides the rate offset threshold as defined by the methods below.
Add-stage methods
ERROR THRESHOLD
For error threshold staging, a stage is added when the error becomes excessive based on degrees away from
setpoint, and time.
ADD-STAGE CONDITION:
- The modulating burner(s) is at its (their) maximum position per the rate allocation rules,
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