MBUSD
24
Wieland Electric GmbH | BA000917 | 01/2019 (Rev. B)
Circuit example of the equipment with a router with data cable length less than
10 m:
Circuit example of the equipment with a router with data cable length more than
10 m:
With an M-BUS data cable more than 10 m it is necessary to use overvoltage protection on
the router side!
6.3
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 protec-
tion can be invoked also by connecting more meters to the bus. They can trigger overcur-
rent 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.
6.4
Port status
LED port indicator
Green LED
Indicates receive data
Yellow LED
Indicates transmit data
Both LED lights
Indicates short circuit on the MBUS
Status indication is supported from 3
rd
revision of boards.
Figure 9: Circuit equip-
ment with a router
with data cable length
less than 10 m
Figure 10: Circuit
equipment with a
router with data cable
length more than 10 m
NOTICE
Table 11: MBUS status
indication
NOTICE
