Boiler Control Instruction & Operation Manual
Page 2
5
of
68
Installation
Energy Management Interface
Table 8: Modbus Signal List
The following is the list of available Modbus signals;
Register addresses start at 0 (zero) based on the Modbus-IDA protocol specification. For more traditional
addressing scheme (starting at 40001) a value of 40001 should be added to the decimal address for each
register.
Modbus
Register
Protocol
Name
Description
Read (R)/
Write (W)
Enable / Disable
577
Central Heat
Enable/Disable
Central Heat Enable/Disable
0 = Disable
1 = Enable
When this register is not written every
“Modbus
Command Time
Out” parameter seconds (default 30
seconds), CH Modbus Stat is reverted to 0, no
demand.
W
563
LLCH Modbus Stat
LL CH Modbus STAT
0 = no demand
1 = demand
When this register is not written every
“Modbus
Command Time
Out” parameter seconds (default 30
seconds), CH Modbus Stat is reverted to 0, no
demand.
W
203
Burner on/off
Burner On/Off burner.
1 = on
0 = off
R
6
Demand source
0 = Unknown
1 = No source demand
2 = Central heat
3 = Domestic hot water
4 = Lead Lag slave
5 = Lead Lag master
6 = Central heat frost protection
7 = Domestic hot water frost protection
8 = No demand due to burner switch turned off
9 = Domestic hot water storage
11 = W arm weather shutdown
R
66
CH heat demand
0=Off,
1=On
R
83
DHW heat demand
0=Off,
1=On
R
123
Low Temperature
Loop heat demand
0=Off,
1=On
R
Setpoints
10,579
CH Modbus
Setpoint
Use this register to change the boiler setpoint.
When this register is not written every
“Modbus
Command Time
Out” parameter seconds (default 30
seconds), setpoint reverts to local setpoint
valid range 60 F to 190 F
W
10,562
CH Sequencer
Modbus Setpoint
Use this register to change the multiple boiler
Sequencer setpoint.
When this register is not written every
“Modbus
Command Time
Out” parameter seconds (default 30
seconds), setpoint reverts to local setpoint
valid range 60 F to 190 F
W
