4.7.10BURNER DEMAND
The stager checks the Master’s LL burner demand. If this demand is off all slaves with SlaveStates of AddStage, SuspendStage, or Firing are set to Available by the Rate Allocator turning them all off and the StagerState is set to be Idle.
STAGERSTATE = IDLE WITH SLAVES ACTIVE If the stager runs and its state is Idle, it checks the status of all slaves. If any of these have SlaveState=AddStage, SuspendStage, or Firing then these are set to Available (this will cause the Rate Allocator to turn them all off).
Stager States
The stager's operation is defined for each of its states:
STAGERSTATE = IDLE
Burner demand means that a demand source is calling for heat and there is also setpoint demand.
When there is no burner demand the stager is forced to be Idle.
When burner demand becomes true (Call for Heat) the stager checks the sequencer to identify the lead boiler. That boiler is given a command to start.
The stager resets (to verify it is at 0) and starts its Stager- Timer, and sets the StagerTimeLimit to the value of the slave's
If the Stager fails to get even one boiler from the Sequencer, it issues an alert and suspends until it runs again.
STAGERSTATE = ADDSTAGERESPONSE During this state the stager is waiting for slave to transition to Firing. If the identified boiler has a SlaveState=Firing then the stager:
Resets and starts it’s StagerTimer, sets the StagerTime- Limit to
If the boiler's SlaveState is still AddStage then:
The stager checks to see if the StagerTimer has reached the StagerTimeLimit.
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Date: 8-4-2010
Revision: 0
Form: 2396
If so then the stager: Changes the SlaveState to Suspend- Stage, resets and starts its StagerTimer, sets the StagerTimeLimit to T_StagerSuspend. This allows additional time for the slave to reach its firing condition.
STAGERSTATE = ADDSTAGESUSPEND During this state the stager is waiting to see if the slave has transitioned to Firing or Available.
If the identified boiler has a SlaveState=Firing then the stager:
Resets and starts its StagerTimer, sets the StagerTime- Limit to
The stager checks to see if the StagerTimer has reached the StagerTimeLimit.
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
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 StagerTime- Limit to
When the Interstage time has elapsed, the