CleaverBrooks CFC Operation, Service & Parts Manual page 400

CB FALCON LEAD/LAG
Example:
Notfiring
Notfiring
Firing
Firing
Firing
Firing
Sequencer Drop Lag boiler selection
When the stager asks the sequencer for a lag boiler to drop
the sequencer looks at the StagingOrder numbers of all
Firing boilers. If only one Firing boiler is found, or none are
found, then this selection function returns a value that indi-
cates no boiler may be dropped. Otherwise it returns an
identifier for the boiler having the highest StagingOrder
number.
SEQUENCER 1 MINUTE EVENT
Part of the sequencer is called by the timing service at a 1
minute rate to implement lead rotation.
The 1 minute event checks the boiler identified by Lead-
BoilerSeqNum. If it is Firing then the LeadBoilerRunTime
is incremented.
FORCED LEAD ROTATION:
When the boiler identified by LeadBoilerSeqNum is firing
and also LeadBoilerRunTime reaches the Force lead
rotation time parameter time then:
1. The current lead boiler is noted.
2. Lead rotation occurs as described above under Vol-
untary Lead Rotation (this changes the designation,
but does not change the actual firing status).
SLAVE WRITE: DATA
This allows the slave to accept command messages from a
CB Falcon master
Before After
3 0
0 0
2 1
5 3
0 4
4 2
56
SLAVE READ: DATA
This provides the slave status message to be read by a CB
Falcon Master. It includes all of the data that is read from a
slave.
SLAVE MODE: USE FIRST, EQUALIZE RUNTIME, USE
LAST
• If set to Use First, then this slave will be used prior to
using other slaves with other values.
• If this parameter is set to Equalize Runtime, then this
slave will be staged according to a run time
equalization. (Any units set to Use First will precede any
that are set to Equalize Runtime.)
• If this parameter is set to Use Last, then this slave will
be used only after all Use First and Equalize Runtime
units have been brought online.
SLAVE PRIORITY SEQUENCE ORDER: 0-255
Slave sequence order is used to determine the order in
which the slaves will be used (staged on) for those with the
same Slave mode setting. Numbers may be skipped, that
is 3 will be first if there is no 1 or 2.
NOTE: For Equalize Runtime purposes, 1 does not
mean the CB Falcon will be used first every
time; that will vary over time based on the mas-
ter's run time equalization scheme. In this case
the sequence number determines the relative
order in which CB Falcon controls will be used
in a round-robin scheme.
If the slave sequence number value is zero, then the slave
CB Falcon's ModBus address will be used instead.
If two CB Falcons are set to the same mode and both have
the same sequence number then an alert will occur and the
order in which they are used will be arbitrary and is not
guaranteed to be repeatable.
750-322