
MMI-BUS devices
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Mounting and installation, Technical Description, T 811 086 en e
7.3.4
MMI-BUS connection with star-shaped power supply
To achieve the highest possible coverage for the conductor cross-section in use for MMI-BUS devices with high current con-
sumption, MMI-BUS devices can also be supplied with star-shaped power from the B6-PSU power supply unit. For the
maximum possible distance of the devices, the distance specification of the individual device applies. Since the data line of
the MMI-BUS is always serial wired, a star-shaped power supply has no influence on the maximum possible total length of
the MMI-BUS (max. 1,200 m).
The power supply may also be provided by an EN-54-2 compliant external power supply unit on site.
GndExt1
VExt1
GndExt2
VExt2
GndExt3
VExt3
GndExt4
VExt4
GndExt5
VExt5
B6-PSU
X5
1
2
3
4
5
6
7
8
9
B6-BCB
MMI-BUS
X6
MMI BUS participant
1
MMI +24VB
MMI +24VA
MMI +24VB
MMI +24VA
MMI GNDB
MMI GNDA
MMI GNDB
MMI GNDA
MMI-BUS data line B
MMI-BUS data line B
Power supply B
Power supply B
Power supply A
MMI-BUS data line A
MMI-BUS data line A
1
MMIBUSA-
MMIBUSB-
MMIBUSA-
BUSGNDA
BUSGNDB
BUSGNDA
BUSGNDB
MMIBUSB-
MMI BUS participant
1
MMIBUSA-
MMIBUSB-
MMIBUSA-
BUSGNDA
BUSGNDB
BUSGNDA
BUSGNDB
MMIBUSB-
1
MMI +24VB
MMI +24VA
MMI +24VB
MMI +24VA
MMI GNDB
MMI GNDA
MMI GNDB
MMI GNDA
Power supply A
Fig. 85 MMI-BUS connection with star-shaped power supply