Chapter 7: Bcm Modbus And Address Assignments; Bcm Modbus Comm. & Support Requirements; Function Codes; Modbus Support Requirements - Watts AERCO EXT Installation, Operation & Maintenance Manual

Ufly Controller and BCM for Modulex EXT

CHAPTER 7: BCM MODBUS AND ADDRESS ASSIGNMENTS

CHAPTER 7: BCM MODBUS AND ADDRESS ASSIGNMENTS
7.1 BCM Modbus Comm. & Support Requirements
The Modbus communication support requirements incorporated in the BCM are as follows:

7.1.1 Function Codes

The BCM supports the Modbus Function Codes shown below.
TABLE 7-1: Supported Modbus Function Codes
FUNCTION CODE
03
04
06

7.1.2 Modbus Support Requirements

The Modbus Network must conform to the support requirements listed below.
TABLE 7-2: Modbus Support Requirements
CHARACTERISTIC
Communication Medium
BMS II/ACS or EMS Master to BCM
Slave
RS485 Allowable Cable Length
Address Support From Master EMS
Transmission Mode Support
Timing Specifications:
Baud Rate:
Data Framing:
Message Framing:
Character Framing:
Heartbeat Timeout:
OMM-0159_A • 6/28/2022
DESCRIPTION
Read up to 8 contiguous Holding Registers
Read up to 8 contiguous Address Registers
Write a single 16-bit Register
RS485 2-Wire Differential Bus With Shield
4000 Feet Maximum
1 to 9 via Address Select Switch (SW1).
(Addresses from 10 to 127 can be implemented via
software)
RTU (Remote Terminal Unit)
Fixed at 9600
8 data bits, no parity, 1 stop bit
Silent period of at least 3.5 character times Before first
character and After last character
No more than 1.5 character times of silence between
received and transmitted characters.
Adjustable (0 or 1 – 240 seconds)
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DESCRIPTION
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