PiXtend eIO Hardware Manual
3.1. Power Supply
All PiXtend eIO devices are operated with a nominal supply voltage of 24 V (DC voltage).
The exact specifications and connection instructions for a suitable power supply can be
found in chapters 5.4
and 6
Technical Data & Connection Notes
This is about the topology of powering several eIO devices in a RS485 bus / network.
Figure 1 shows the correct wiring or power supply topology for multiple PiXtend eIO
devices. Each device is approached separately from a common supply or ground point
with its own lines.
The conductor cross-section, especially of the ground lines, should be much larger than
the signal lines for the RS485 bus. This has the background that the supply current of the
modules (comparatively large current) should be dissipated via the supply connection and
not via the GND connection, which belongs to the RS485 network.
Ideally, a separate power supply is used for the digital outputs of PiXtend eIO Digital One
devices. But a separate protection for the supply of the outputs is a legitimate way.
In any case, the supply connections of the outputs to the supply and a GND line are
connected.
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Figure 1: Topology of the power supply
