75
MASTER SELECT METHOD
This parameter provides for the selection of the master boiler via the
keypad, digital input or communications. The available selections are:
UNUSED:
No SEQUENCING selected, operates on own PID.
KEYPAD:
Master selection via the Keypad - the LEAD/LAG button
is used to select the master.
INPUT:
Master via digital input. (Refer to DIGITAL INPUT select)
COMMS: Master selection via modbus communications.
LEAD/LAG LED Status
The LED associated with the LEAD/LAG push button is active only when the master select method
is KEYPAD can have the following state:
OFF
Boiler is in slave mode
ON
Boiler is in master mode
BLINKING
Boiler is transitioning from slave to master, or from master to slave.
Note: Status of sequencing master can also be verified by hitting the HOME key and revewing the
top line. If sequencing master is active, the top line should read AUTO(m)
SEQUENCING CONFIGURATION
The master boiler is programmed as to how many slaves exist, the order in which slaves are turned
on, the modulation firing rate that, when exceeded, will begin the slave turn on procedures and the
delay on and off time for each slave to be turned on and off. Below is a table showing parameters
programmed into each master. The value in the last column of the 1st, 2nd, and 3rd Slave On values
are the communication addresses previously mentioned that the slaves are set to within each of their
own “Communication” setup menus.
SLAVES AVAILABLE
Each master is programmed as to how many slaves it will be controlling. The minimum is 0 and the
maximum is 5. The remaining items in the SEQUENCING sub menu will be dependent on the
slaves available.
1ST SLAVE ON (communication address)
2ND SLAVE ON (communication address)
3RD SLAVE ON (communication address)
The order in which each slave is commanded on is programmed into the master's parameters using
each slave's communication address to identify each slave. Each boiler must have its own unique
communication address identifier. Each boiler in the system, if it can be a master, must indicate the
priority order of the remaining boilers in the system. The priority is not restricted to ascending or
descending addresses. In fact, each master can have a different priority order of the remaining slaves.
Note: Communication addresses should NEVER be changed while the boilers are in sequencing
(more than one boiler on). Established operation will be disrupted.
S
L
A
V
E
S
A
V
A
I
L
A
B
L
E
3
>
1
S
T
S
L
A
V
E
O
N
3
<
2
N
D
S
L
A
V
E
O
N
2
3
R
D
S
L
A
V
E
O
N
4
