Boiler Parameter Worksheet
Appendix
44
20
HIGH
Analog In
20
LOW
Analog Out
22
BOTH
Ignitions
1/16
th
of Ignitions
24
BOTH
Burner High Hours
Hours
26
BOTH
Burner Medium Hours
Hours
28
BOTH
Burner Low Hours
Hours
30
HIGH
Information Byte
See Information Byte
30
LOW
ET Error Number
See Error List
Section 3.2 and 3.3
32
HIGH
ET Supply Temp
Normal Temperature
32
LOW
ET Return Temp
Normal Temperature
34
HIGH
ET DHW Temp
Normal Temperature
34
LOW
ET Flue Temp
Flue Gas
Temperature
36
HIGH
ET HX Temp
Normal Temperature
36
LOW
ET Outside Temp
Outdoor Temperature
38
HIGH
ET Sequence
See Sequence Byte
38
LOW
ET Month
See BCD Byte
40
HIGH
ET Day
See BCD Byte
40
LOW
ET Year
See BCD Byte
42
HIGH
ET Hours
See BCD Byte
42
LOW
ET Minutes
See BCD Byte
44
HIGH
ET Day Count High
44
LOW
ET Day Count Low
46
BOTH
ET Run Hours
Hours
Depending on the type of MODBUS
®
software used, the holding register addressing range starts either at 0x0000 or
at 0x0001. If your MODBUS
®
software starts at 0x0000 you can use the holding register addresses shown in the
tables above. If your MODBUS
®
software addressing range starts from 0x0001 then add 1 to the holding register
addresses listed in the tables above.
3.0.1
Descriptions of MODBUS
®
Register Map
Normal Temperature formula
The temperature is scaled between -
10…+118°C (14°F – 244°F). The formula to calculate the actual temperature
using the value of Supply Temperature is as follows:
I) Temperature [°C] = (Supply Temperature ÷ 2) - 10
II) Temperature [°F] = Temperature [°C] × 1.8 + 32
Outdoor temperature formula
Some temperatures are scaled between -40°C and 88°C (-40°F
– 190°F). The formula to calculate the actual
temperature is:
I) Temperature [°C] = (outdoor temperature ÷ 2) - 40
II) Temperature [°F] = Temperature [°C] × 1.8 + 32
Flue gas temperature formula
Some temperatures are scaled between 10°C and 138 °C (50°F
– 280°F. The formula to calculate the actual
temperature is:
I) Temperature [°C] = (flue gas temperature ÷ 2) + 10
II) Temperature [°F] = Temperature [°C] × 1.8 + 32