Xylem Sensus Modbus RTU User Manual

User Manual
Modbus RTU
Option module for PolluTherm
1. Use of the option module
The Modbus RTU
to Modbus RTU network using EIA-485 channel.
The module is based on Modbus RTU Slave protocol which is realized according to newest specifications
published by Modbus. The module EIA-485 network interface is compliant to TIA/EIA-485 standard.
1.1. Power supply
The Modbus RTU module should be powered by AC or DC (polarity insensitive) SELV power supply only.
SELV Power Supply Voltage
Power Supply Terminals
Power Consumption
Typical Supply Current
1.2. Communication interface
Connection to Modbus RTU network is realized by using galvanic isolated EIA-485 network interface.
Communication Protocol
Network Polarity
Transmission Speed/Baud Rate (bits per second)
Data Format
Galvanic Isolation between Network and Option Module
Number of Devices per EIA-485 Segment Channel
EIA-485 Network Topology
EIA-485 Segment Channel Length
The default communication parameters are: 9600 bps baud rate, 8N1 data format, Modbus Slave ID – 1.
Use only the dedicated two terminators on both ends of EIA-485 network channel segment. In case of any
question, please contact technical support.
1.3. Environmental requirements
Operating Temperature (ambient)
Storage Temperature
Operating and Storage Humidity
option module is used
Picture 1: Modbus RTU module
to connect the PolluTherm
12-24 V AC/DC ±10%
60 and 61 (polarity insensitive)
max. 0.6 W
32 mA @12 V DC
Modbus RTU
90 (non-inverting, +) and 91 (inverting, -)
1200, 2400, 4800, 9600, 14400, 19200,
38400, 56000, 57600, 115200
8E1 (8 data bits, even parity bit, 1 stop bit),
8O1 (8 data bits, odd parity bit, 1 stop bit),
8N1 (8 data bits, none parity bit, 1 stop bit),
8N2 (8 data bits, none parity bit, 2 stop bits)
299 V (0-60 Hz)
RMS
Up to 256 (⅛ UL)
Bus Topology
1200 m
+5 to +50°C
-10 to +65°C
25 to 90 % RH @50°C, non-condensing
heat meters
M H 6123 INT, page 1