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M-bus
Address
M-bus uses two types of addresses to recognize devices:
●
Primary addressing: Up to 250 primary addresses can be assigned to a M-bus system.
The primary address is normally assigned during device commissioning. Pure primary
addressing is not possible if more than 250 devices are read on the M-bus network.
●
Secondary addressing: Secondary addressing consists of 8 bytes and permits the
assignment of any number. In the default setting, the secondary address for a device
normally matches the serial number issued by the device manufacturer. The assignment
prevents address conflicts on the bus.
Bus expansion
Plant type
Small residential
buildings
Large residential
buildings
Small
developments
Large
developments
Direct vicinity
Point-to-point
connection
*Shielded cabling required at a distance in excess of 1000 m (see EN13757-2 appendix E).
Signal specification
M-bus
Number simple
M-bus loads per
segment
Transmission
rate
Bus power
(Master)
Bus current
(master)
10
Smart Infrastructure
Maximum
Total cable
distance
length
350 m
1000 m
350 m
4000 m
1000 m
4000 m
...3000 m*
5000 m
...5000 m*
7000 m
...10000 m*
10000 m
Condition
Minimum
WTX631-
0
GA0090
≤ 382 nF
C
300
Segment
WTX631-
30
GA0090
WTX631-
0
GA0090
Cable cross
Number of
section
devices (slaves)
2
0.8 mm
250
2
0.8 mm
250
64
2
0.8 mm
64
2
1.5 mm
64
2
1.5 mm
16
2
1.5 mm
1
Typical
Maximum
-
250
2400
9600
39
42
-
375
Max.
transmission
rate
9600 baud
2400 baud
9600 baud
2400 baud
2400 baud
300 baud
300 baud
Measuring unit
-
baud
R
mA
A6V11742346_en--_a
2019-10-01
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