Expansion port MBUSD
Wieland Electric GmbH | BA000917 | 08/2021 (Rev. C)
21
Circuit example of the equipment with a router with data cable length more than 10 m
Figure 10: Circuit equipment with a router with data cable length more than 10 m
With an M-BUS data cable longer than 10 m it is necessary to use overvoltage protection on the
router side!
5.3
Overload detection
When a short-circuit is detected on M-BUS, power of the bus is disconnected. Then the bus is
checked every 4 seconds by connection of power supply and measuring of current consumption. If
the bus is still shorted, then power is disconnected again. Bus is once again operable approximately
8 seconds after short-circuit subsides. Short-circuit protection can be invoked also by connecting
more meters to the bus. They can trigger overcurrent detection by their own power consumption.
Overcurrent protection can be triggered also by connecting a critical number of meters, when power
consumption can rise above the limit during communication.
5.4
Port status
LED port indicator
Green LED
Indicates data reception
Yellow LED
Indicates data transmission
Both LED lights
Indicates short circuit on the MBUS
Status indication is supported from 3
rd
revision of boards.
5.5
Technical specifications
Expansion port M-BUS
External power supply Voltage
+10 … +30 V
Supply power
Max. 4 W
Environment
Operating temperature
-30 … +60 °C
Storage temperature
-30 … +85 °C
Standards
Emission
EN 55022/B
Immunity
ETS 300 342
Safety
EN 60950
M-BUS specifications
(EN 1434)
Max. devices (each 1,5 mA)
30
Max. operating bus current
60 mA
Overload detection
100 mA
Short circuit strength
Permanent
Bus voltage mark
36 … 43 V
Bus voltage space
24 … 31 V
Max. total cable length (300Bd, 200nF/km)
1000 m
NOTICE
NOTICE
