36 Connect Devices
WAGO-I/O-SYSTEM 750
753-649 M-Bus Master Module
Manual
Version 1.1.2
6.3
Important Installation Notes
Do not work when devices are energized!
High voltage can cause electric shock or burns.
Switch off all power to the device prior to performing any installation, repair or
maintenance work.
6.3.1
Field Supply
Observe tolerance range of the field supply
The correct function of the M-Bus interface is only ensured if the voltage of the
field supply is in the range 23.4 VDC … 25.2 VDC.
When continuously illuminated, LED E indicates that the supply voltage is in the
permissible range. When LED E blinks, the supply voltage is outside the
permissible range (see section “Device Description” > > … > “Display Elements”).
Ensure stable power supply
Due to interference from other I/O modules or the use of power supplies with
tolerances that are too high, the quality of the supply voltage may be insufficient,
impairing the operation of the M-Bus master.
In that case, it is necessary to use an additional bus supply module and an
additional appropriate power supply. The power supplies recommended for use
with the M-Bus master are listed in the section “Technical Data” > “Power
Supply”.
