ABB A43 User Manual

Communication with M-Bus
A43/A44 174 2CMC48001M0201
User Manual Revision: C
10.1 Bus Description
General
M-bus is a 2-wire polarity independent bus, optimized for master-slave commu-
nication with gas, water, heat and electricity meters. Number of meters on one
physically connected bus is 1-250. A bus can be extended by using a repeater.
Topology
M-bus topology is flexible and star, line, tree topology or a mix of these can be
used, see figure below. Ring topology can not be used. Bus termination is not
required.
Cable It is recommended to use non shielded twisted pair cable with wire area of 0.8
mm
2
, for example two-wire standard telephone cable JYStY N*2*0.8 mm
2
. If
shielded cable is used the shield must not be connected to any of the two bus
wires. Maximum total length of the bus is 1000 m. Maximum length between a
slave and a repeater is 350 m.

ABB A43 Specifications

General

Brand	ABB
Model	A43
Category	Measuring Instruments
Language	English