Siemens SCALANCE M812, Operating Instructions Manual, Page: 46 / 74

External power supply
Note
Permitted external power supplies
The power supply unit to supply the SCALANCE M826 must comply with the requirements for
a limited power source (LPS) according to IEC 62368-1.
The external power supply for the SCALANCE M826 must meet the requirements for NEC class
2 circuits as specified in the National Electrical Code ® (ANSI/NFPA 70).
Refer to the section Connecting up (Page 41) and the installation instructions and
instructions for use of the manufacturer of the power supply, the battery or the accumulator.
Note
The requirements of EN61000-4-5, "Surge Immunity Test" on power supply lines with 24 VDC are
met only when a Blitzductor is used:
24 VDC: BVT AVD 24 type no. 918 422
Vendor: DEHN+SÖHNE GmbH+Co.KG, Hans Dehn Str. 1, Postfach 1640, D - 92306 Neumarkt,
Germany
5.3 Grounding
A functional grounding must be established for example by connecting a cable from terminal 5
to the DIN rail, refer to the section "Power supply (Page 45)“ or section “Terminals (Page 23)“.
Such a cable should be kept as short as possible.
If cables are installed permanently, it is advisable to remove the insulation of the shielded
cable and to establish contact on the shield/PE conductor bar.
5.4 Digital input/output
The digital input and output are connected using a 2-pin plug-in terminal block in each case. Two
terminal blocks ship with the device.
CAUTION
Damage due to voltage being too high or too low
The voltage at the digital input/output must not exceed 30 VDC and not fall below -30 VDC,
otherwise the digital input/output will be destroyed.
Connecting up
5.4 Digital input/output
SCALANCE M826
46
Operating Instructions, 10/2022, C79000-G8976-C362-07