Falcon Lead Lag Appendix E
E-16
Slave enable should be set to ‘Enable slave for built-in Lead Lag master’. The ‘Enable slave for third
party’ setting is for use with external (non-Falcon) control.
Some Falcon versions may indicate ‘Slave’ and ‘Modbus Slave’ as the choices for this parameter. In
this case select ‘Slave’ (NOT ‘Modbus Slave’).
Slave mode - If set to Use First, this boiler will be used prior to any with other values. If set to
Equalize Runtime, then this boiler will be staged according to a run time equalization algorithm
(any boilers set to Use First will precede any that are set to Equalize Run Time). If set to Use Last,
then this boiler will be used only after all Use First and Equalize Runtime boilers have been brought
online.
Slave sequence order - if set to 0 will use this Slave’s Modbus address.
Demand to firing delay - This delay time is needed by the LL master to determine the length of time
to wait between requesting a Slave 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
timers as transition to purge rate, prepurge time, transition to lightoff rate, all ignition timings, and
some extra margin.
Fan rate during off cycle - This determines if or at what rate the fan is to operate during the standby
period. It may be advisable in some installations to set this parameter so as to prevent flue gas from
entering the boiler room through an idle boiler.
Modbus port is MB2.
Modbus address This will eventually need to be set to a unique address on each slave boiler. This
can be done after copying parameters to all slaves (see 7.4 below).
7.3 - Copying parameters to remaining slaves
The procedure below will copy the first slave’s parameter set to remaining slaves. See also 750-244
PIM manual.
1. Remove the Program Module slot cover from the Master host controller and insert a Falcon 833-
3640 Program Module (‘PIM’ or ‘PM’). See <Color>Figure 6.
Table 3 - Lead Lag Slave Configuration Parameters
Parameter Range CB Default Setting Installation Setting
Slave enable Enable slave for built-in Lead
Lag master
Enable slave for third party
Lead Lag master
Disabled
Disabled
Slave mode Use first
Use last
Equalize run time
Equalize run time
Base load rate ignored
Slave sequence order 0-8 0 (= use Modbus address)
Demand to firing delay hr min sec 3 min
Fan rate during off cycle 0-6500 RPM 0
Modbus port MB1
MB2
No port
MB2
Modbus address 1-8 1
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