Dräger REGARD 3900 Series Instructions For Use Manual page 18

Installation & commissioning
5.5.1 AC power supply
If the internal 24 V DC power supply unit is not provided by Dräger, it must be
ensured that the requirements of the EMC (electromagnetic compatibility) Directive
and the Low Voltage Directive have been met. The power supply unit must comply
with the following EMC standards - Immunity: EN 61000-6- 2; Emissions:
EN 61000-6-3 or EN 61000-6-4.
If the AC voltage supply comes from an AC power socket, the maximum length of
the cable between the socket and the control unit is 3 m.
For the AC voltage supply, use a 24 V DC power supply unit as shown in the image
below. The power supply unit should be chosen according to the number of input
channels used.
Dräger recommends the following:
– 4 channels - 2 A energy supply unit.
– 8 channels - 5 A energy supply unit.
– 12 or 16 channels - 10 A energy supply unit.
5.5.2 DC supply voltage
To supply the control unit via an external DC power supply:
– Use a regulated, fault-free 24 V DC power supply.
– If it is likely that the supply will be exposed to high levels of conducted RF
interference, use a filter to eliminate the interference.
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REGARD 3900