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RBFU 3.20 Field Unit

RBFU 3.20 Field Unit

  • Digital I/O field unit
  • 8 digital inputs (potential free)
  • 4 digital outputs (relays)
  • for DIN rail mounting
  • 230 V AC mains power
  • Programmable relay outputs safe state.
Category: .

Product Description

RBFU 3.20 has 8 digital inputs and 4 digital outputs. It is mountable on DIN rail. Inputs are potential free contacts. Outputs are NO relay contacts. The unit is connected to the Ringbus master controller via a 4 wire ring bus communication. Each unit has a predefined address and therefore has not to be addressed during the system commissioning. RBFU 3.20 ST unit is able to work without 230 V, but then it is only sending information about its power supply condition and is not able to turn on/off the outputs or to read inputs. Relay outputs will go in to preprogrammed safe state if communication is lost for more than 10s or around 1s after loss of the external power. Possible safe states are CLOSE, OPEN and STAY

Additional Information

Electrical data


Nominal voltage range

AC 100 … 230 V 50/60 Hz

For wire sizing

2 VA

Power consumption from mains

1 W

Power consumption from bus

5 mW


Power supply terminal 3 x 1.5 mm² wire
8 inputs terminal 16 x 1.5 mm² wire
4 outputs terminal 8 x 1.5 mm² wire
2 x RingBus terminal 4 x 1.5 mm² wire

Wire stripping length

10 mm


Potential free contacts, optically insulated


Latch relay

Output max load

Resistive: 0.2A at 250VAC; 2A at 30VDC
Inductive: 0.1A at 250VAC; 1A at 30VDC



Degree of protection



CE according to 2004/108/EC


CE according to 2006/95/EC

Ambient humidity range

IEC 60730-1 max. 95 %

Ambient temperature range

–20 … +60°C

Non-operating temperature

–40 … +85°C





450 g
137 × 127 × 50 mm


Technical Data Sheet for RBFU 3.20 Field Unit