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Date: 8-4-2010
Revision: 0
Form: 2396
off all slaves and enters an idle or standby
condition.
4.7.2 PERIODIC DATA POLLING
MESSAGES
The LL master uses polling to discover new
slave Sola devices and to periodically refresh
the information it has about a known slave Sola
devices. Thereafter it polls the known devices to
make sure they are still present and to obtain
updated status information. It also periodically
polls the entire slave address range to discover
any new slave devices. A polled Sola is read to
determine the values of the following data items:
a. The slave's type (compatibility) as indicated
by the Slave type b. The slave enable status
Slave enable c. The slave mode as set in Slave
mode d. The slave sequence order as set in
Slave sequence order e. Demand-to-firing
delay: mm:ss or None This delay time is
needed by the LL master to determine the length
of time to wait between requesting a slave Sola
to fire and detecting that it has failed to start. It
should be set to the total time normally needed
for the burner to transition from Standby to Run,
including such things as transition to purge rate,
prepurge time, transition to lightoff rate, all
ignition timings, and some extra margin. f. CT -
Burner run time This parameter will be needed
if measured run-time equalization is being used.
Slave Control
The LL master sends each active slave a
command and also performs a slave status read
for each known slave device. It also sends a
Master status broadcast that is heard by all
slaves. There are 5 commands that might be
sent:
• All slaves are commanded to turn off and
remain off.
• The LL master sends message to Solas that
are off, to turn their fans on.
• The LL master suspends operation which
request a burner to recycle and remain in
Standby if it has not yet opened its main valve
(e.g. it is in Prepurge or PFEP) but to keep firing
if it has reached MFEP or Run. This suspend
may be for the fan to be on or off in standby.
This message is used to abort the startup of a
slave that is not yet firing (because demand
went away just before it was firing), but to keep it
on if it actually is firing (the LL master will
discover what happened in a subsequent status
response). The LL master also sends this
message to a slave that is OnLeave. (This
ensures that if the slave is firing when it returns
to LL master control, it will stay that way until the
master has decided whether to use it; or
conversely, if the slave stops firing for some
reason that it will not start up again until the LL
master has requested this. In either case, the
command will be to turn on the off cycle fan if
any other slave burners are firing, or to turn the
fan off if the slave is the only slave that might (or
might not) be firing.
• The LL master sends message to turn the
burner on and to assign the burner’s firing rate.
If the commanded modulation rate is less than
the burner’s minimum modulation rate, then the
burner should always operate at its minimum
rate.
4.7.3 SLAVE STATUS MANAGER
The LL master keeps track of slave status for
each Sola that is enabled as a slave device. The
slave status manager operates internally for
each slave Sola devices (up to 8). There is a
table entry for each device containing the
following data:
• SlaveState:
Unknown - indicates the table entry is unused
and empty
Available - indicates the slave is OK and ready
to use, but is not
currently firing as a slave
AddStage - stage is getting ready to fire
SuspendStage - stage was getting ready but is
not needed
Firing - indicates the slave is currently firing
OnLeave - indicates the slave is operating for
some other demand source within it that has
higher priority than slave demand.
Disabled - indicates the slave is locked out or
disabled in some way
Recovering - indicates the slave is in a time
delay to ensure that it is OK before it is again
considered to be available.
• RecoveryTime: Saves how long the slave
must be OK to recover.
• RecoveryTimer: Used to measure the slaves
recovery time
• RecoveryLimitTimer: Enforces a maximum
slave recovery time
• DataPollFaultCounter: Used to tolerate
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