User Manual

Safety notes
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CAUTION
NEC (North
America)
Use of class 2 transformers limited to 100 VA or class 2 circuits at max. 100 VA
by a non-limited transformer of max. 400 VA, combined with overcurrent
protection (T 4 A fused) for each AC 24 V device. Multiple fuses for multiple
insulated secondary circuits per transformer are possible (see Power
requirements [➙ 28]).
The same applies to DC 24 V power supplies.
CAUTION
Device safety
Device-related safety is guaranteed, among others, by low voltage power supply
AC 24 V, DC 24 V and double insulation between the mains voltage AC 230 V,
AC 24 V circuits and the housing or Power over Ethernet (PoE Class 4).
Comply with specific regulations for electrical wiring per the following sections.
CAUTION
Grounding
⊥
(system neutral AC/DC 24 V)
Observe the following points when grounding ⊥ AC 24 V (system neutral):
● Operating voltage of AC 24 V is permitted in principle for both grounded as
well as non-grounded system neutrals. Local regulations and customs apply
accordingly. Grounding may be required or not allowed for functional reasons.
● Recommendation: AC 24 V systems are generally grounded unless otherwise
not recommended by the manufacturer.
● In order to avoid ground loops, connect systems with PELV to the ground at
one location only (especially for transformers), unless otherwise indicated.
●
The same applies to DC 24 V power supplies.
CAUTION
Functional ground
The connections of the functional earth must be connected on the installation side
with the building grounding system (PE).
CAUTION
Operating voltage AC/DC 24 V
It must meet requirements for SELV or PELV. Permissible deviation to nominal
voltage:
At the transformer/power unit: AC / DC 24 V -10 … + 20%
At the end device (web server): AC 24 V ±20%, DC 24 V ± 20%
At the end device (touch panel): AC 24 V ±20%, DC 24 V ± 20%