Boiler Parameter Worksheet
Appendix
47
Notice how the decimal values are equivalent (4257) in both programs. These procedures assume the MODBUS
®
program starts the address registers at 40001. If the program starts the address registers at 40000, subtract one from
the address register shown in each procedure.
The procedures described in this bulletin require the user to pull a single MODBUS
®
register from one boiler at any
given time. Multiple register requests or simultaneous register requests from multiple boilers are not discussed in this
bulletin. It is also important to note that different MODBUS
®
programs will display data in hexadecimal, decimal or
binary format. These procedures require all addresses to be displayed as decimal values.
In addition, there are several procedures which require integer division. These particular operations are indicated by
(Integer) and two examples of standard division vs. integer division are shown below:
Standard Division:
o
40869 ÷ 256 = 159.644
Integer Division:
o
40869 ÷ 256 = 159
Standard Division:
o
15 ÷ 1.8 = 8.333
Integer Division:
o
15 ÷ 1.8 = 8
Useful abbreviations:
CH = Comfort Heat
DHW = Domestic Hot Water
ET = Error Text (Data captured at the time of the failure)
HX = Heat Exchanger
OA = Outdoor Air
The E-104 MODBUS Calculator.xls Excel spreadsheet and M-105 MODBUS Calculator.xls will be very helpful in
performing the calculations shown in the procedures below. The E-104 calculator is designed for reading single
registers while the M-105 calculator is designed for reading multiple registers simultaneously which is more
frequently helpful when integrating to a building management system. These calculators are available under the
“Technical Data” section of www.harscopk.com.