Table of Contents
Advertisement
9. Installation of M-Bus
An M-Bus system is mounted with bus topology,
which means that all M-Bus Slaves are coupled to
the M-Bus system in parallel. You start from the
M-Bus Master, into the first M-Bus Slave, from the
first M-Bus Slave and on to the next one etc.
The M-Bus Master has two sets of parallel termi-
nals, which makes it possible to divide the M-Bus
in two halves in order to facilitate later error detec-
tion.
The M-Bus terminals have the numbers 24 and 25.
The M-Bus is independent of polarity i.e. it is at no
consequence how the M-Bus wires are connected
to terminals 24 or 25.
A M-Bus Slave is mounted in MULTICAL
ting the M-Bus Slave at the module place and
mounting the M-Bus cables. Before the identifi-
cation number can be entered in the M-Bus Slave,
the M-Bus Slave must be either reset or initiated.
We recommend that the whole M-Bus system is
switched off when mounting new M-Bus Slaves.
When all M-Bus Slaves have been connected,
the M-Bus system is started (the current to the
M-Bus Master is switched on). This start will reset
all M-Bus Slaves.
Mounting
M-Bus connection
Introduction of M-Bus
Serial data output line
and data cable
M-Bus Slaves can also be mounted without the
M-Bus system being switched off. This means that
SND_NKE must be sent to address 255 when all
M-Bus Slaves have been mounted in order to ini-
tiate them. Failing to do so, the connected M-Bus
Slaves will not collect their ID-numbers, so that
the M-Bus Master can contact them, until 12 hours
later.
Cable length
The cable length depends on the cable resistance
and capacity. The cable resistance depends on the
cable type and above all the cross section.
General demands:
®
by inser-
The resistance R must be less
than 29 Ω/km.
The capacity C must be less
than 180 nF/km.
If e.g. a cable of 2 x 0.8 mm
approx 1.800 m cable is used in total in the M-Bus
system based on 40 M-Bus Slaves.
In addition – see tabel on page 11
Modular space for M-Bus Modem
Supply
or M-Bus Cascade module
230 VAC
2
is used, in practice
Introduction of 230 VAC
Botton of the M-Bus Master
13
Hide quick links:
Advertisement
Table of Contents
