Chapter 2. standard register assigments, 1 introduction, 1 input registers – AERCO Modbus Communications Manual User Manual
Page 13: 2 holding registers, Modbus, Communication

Chapter 2
MODBUS
Communication
GF-114
Standard Register Assignments
USER MANUAL
OMM-0035_0C
05/18/12 AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Page
13 of 200
CHAPTER 2. STANDARD REGISTER ASSIGMENTS
2.1 INTRODUCTION
This Section provides the standard data register addresses assigned to the AERCO and C-
More Boiler Controllers, the AERCO Boiler Management System (BMS/BMS II), and AERCO
Control System (ACS). These data registers consist of Input Registers and Holding Registers.
All register addresses provided throughout this manual are expressed as hexadecimal numbers.
2.1.1 Input Registers
The Input Registers for the AERCO C-More Boiler Controllers and AERCO BMS/BMS II/ACS
are intended for information and functions that cannot or should not be controlled remotely.
Therefore, unless otherwise specified, ALL Input Register data are READ ONLY.
IMPORTANT
All Modbus addresses specified in this manual are written
generically in decimal/hexadecimal format. However, many
Building Automation Systems utilize another form of addressing
where:
40001 is added to the generic address for a Holding Register
address.
And
30001 is added to the generic address for an Input Register
address. Be sure to check the addressing scheme being used by
the BAS that is being interfaced to the XPC Gateway.
2.1.2 Holding Registers
The Holding Registers for the AERCO C-More Boiler Controllers and AERCO BMS/BMS II/ACS
are intended for information and functions that can be read or written (R/W). Therefore unless
otherwise specified, all Holding Register data are R/W.
CAUTION
DO NOT write in any Register Addresses marked as “Reserved” in
the Input Register and Holding Register Tables which follow.
Failure to observe this precaution may result in unstable
operation.