Interbus® – a Fieldbus System

Interbus® is an internationally used fieldbus system. Since the first presentation of the  system in 1987 the Interbus® has been  modified, updated and improved and has  become integral in numerous applications  in the area of Automation Technology.

Lumberg Automation Products

To ensure the best application of the Interbus®  in the decentralized sector, components  must meet maximum electromechanical  demands. The Lumberg Automation Interbus®  components offer maximum protection for the electronic system due to the material used for the housing and the potting tech-nology. The connection for Interbus® and the power supply of the module electronics, sensors as well as actuator system is imple-mented via M23 connectors. Bus terminals or TAPs are available for the connection to the bus.

General Technical Data

Transmission medium

•  Shielded twisted pair copper cable for differential signal transmission acc. to RS422 (RS485)

• Hybrid cable for the joint transmission of power supply and data with the installation remote bus

Network topology

Physically, Interbus® is configured as a ring. Due to special cabling systems (e.g. transmit and return lines in one cable, special T-splitters) it resembles a tree structure.

Partial systems in the Interbus®

•  The Remote Bus (RBUS) has been designed for long distances. It connects the master with the first bus terminal and general remote bus participants with each other. A drop line from the remote bus is permitted and called a remote bus drop.

• The Installation Remote Bus is a variant of the remote bus. Apart from actual data cordsets the power supply for the module electronics and sensors is conducted in the Installation Remote Bus Cable.

• A Local Bus (LBUS) is a bus connection branching from the remote bus via a bus terminal and connecting the local bus participants with each other. Different variants of the local bus exist.

Number of devices

•  Maximum 254 remote bus participants

• Total of 512 participants with max. 4096 I/O points

Admissible transmission rates and line lengths

•  Transmission rate: 500 kBit/s

• Overall remote bus length: 12.8 km

• Maximum distance between remote bus participants: 400 m

• Length of the installation remote bus: 50 m

• Distance between installation remote bus participants: 50 m

• Admissible current load of the installation remote bus: 4.5 A

Addressing

Modules are addressed automatically during the start-up of the bus depending on the physical position of the participants in the bus.