Zener barriers contribute to the intrinsic safety [Ex i] and are installed in safe areas. Their mission is to limit the level of energy that may appear in an electric circuit routed through a potentially explosive area, whatever the connection established upstream of the barrier.
A barrier is made up of:
- resistors that limit the current
- Zener diodes that limit the voltage
- fuses that protect the components

When a fault voltage is applied across the input terminals of the barrier, the voltage that may appear in the explosive zone is limited by a Zener diode, which is in turn protected by a fuse.
The current is limited to an acceptable value by the resistor.
They can be installed in zone 2, thanks to the Ex nA certification in an IP 54 housing.

Zener barrier for analogic signals
Polyester enclosure / DIN Rail mounting
For earth grounded wiring
3/4 & 7/8: U0=27.3V I0=95.79mA P0=653.76mW
2/3: Ua=26.8V Ifm=50mA RL=311.3ohm
Number of channels: 2
Screw terminals

ATEX / IECEx informations:
INERIS 11ATEX0024X / IECEx INE11.0009X
Group II (surface) - category (1) G/D
II(1) GD [Ex ia Ga] IIC, IIB or [Ex iaD Da] IIIC
II3(1) G Ex nA [ia Ga] IIC T4 Gc
Installation in safe zone or zone 2
For equipment installed in zone 0,1,2,20,21,22
See leaflet for a safe use