SB1 Safety Barrier

Two-channel safety barrier for intrinsically safe transmitters

Ex-Zone 0 environments place high demands on gas detection devices. They cannot cause the ignition of a flammable atmosphere at any time during normal operation or in the event of faults. There are therefore limit values for voltage and current that must be observed. To connect an intrinsically safe transmitter in Ex zone 0, an intrinsically safe circuit must first be set up. To connect the intrinsically safe circuit to one that is not, a safety barrier is required. This is the purpose we developed the SB1 in wall-mounting housing for.

In Ex-Zone 0, limit values for supply voltage and current must not be exceeded at any time. To integrate an intrinsically safe transmitter into an existing 4-20 mA signal transmission, a safety barrier can be interposed between the two elements. The SB1 uses resistors to limit the input voltage from 24 V DV to a maximum output voltage of 21 V DC.

The SB1 safety barrier is installed outside the hazardous area. It transmits 4-20 mA signals between intrinsically safe and non-intrinsically safe circuits. The intrinsically safe circuit originating from the safety barrier is routed into the Ex zone 0 and supplies an intrinsically safe transmitter with an operating voltage of 21 V or less. Depending on the transmitter, it can be connected via a 2-wire or 4-wire cable. The supply module is connected to the controller via a 3-wire cable.


Key features at a glance:

  • Transmitter supply module suitable for the intrinsically safe EC28 i, EC28 Di, IR29 i and IR29 Di transmitters
  • Transmission of 4-20 mA signals between intrinsically safe and non-intrinsically safe circuits
  • 3-wire 4-20 mA lines to 2-wire or 4-wire lines in Ex zone 0
  • ATEX certification: II (1)G [Ex ia Ga] IIC
  • Also available as SB1 D with integrated 2.2" display
  • Input voltage: 22 to 30 V DC (max. fault voltage 253 V AC)
  • Output voltage: 21 V
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