Manual
| System Manual
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3.3 Power Supply
3.3.1 Configuration Notes
Bus modules require a direct-voltage power supply of typically 24 VDC (SELV/PELV) which must
comply with the regulations of conventional industrial power-utility companies.
In order to optimize interference immunity, we advise you to power sensors, bus, and
actuators from different sources. The power supply should be primary switched-
mode or regulated power supplies.
The output of the power supply units depends on the number of connected load and their output.
In any case, it must be ensured that the system voltage does not drop below 18 V DC
viewed from the system power supplies and measured at the remotest slave. System
response becomes unspecific if sensor and bus power supply drop below 18 V DC.
Primary switched-mode power supply units normally permit an increase in output
voltage to the amount of the rated voltage in order to compensate for any power
losses.
Modules with digital inputs support the direct connection of commercially available sensors. A sepa-
rate power supply may be necessary for the sensors if the total power required is high due to the
number of slaves or a high power draw of the sensors.
The sensor supply may only be provided via the bus node into the system.
Back discharge by sensors or by an external supply in order to increase the maxi-
mum current is not allowed.
Protecting cables between power supply and bus node:
Cable protection in the form of an intelligent current monitoring or a fuse has to be
provided in order to detect damages of the supply cable and to shut down in case of
failures.
