Industrial Communication Guide

Fieldbuses

3.4. OVERVIEW OF THE INDIVIDUAL FIELDBUSES

Disadvantages of the fieldbus • Complexity requires qualified personnel for operation and main- tenance • More elaborate in terms of measuring technology • Longer response times due to sequential accessing of slaves (depending on the fieldbus in question) • Failure of the bus system causes failure of communication be- tween all components

The following table gives an overview of well known fieldbus sys- tems. The following aspects are distinguished:

• Transmission medium: What type of cable (shielded/unshield- ed, no. of wires) has to be used? Sometimes it also possible to use fiber optic cables (FO). • Connectors: Which type of connector can be used (depending on requirements with regard to degree of protection, EMC)? Which connection technologies can be used? • Topology: What is the structure of the fieldbus or how are the individual components connected to one another? • Maximum no. of components: How many components can the bus system address? • Energy supply via the bus: Does the fieldbus allow the cable to be used for power supply and data transmission at the same time? • System developer: Which company or which organization pro- duced the fieldbus? • Advantages and disadvantages: What are the strengths and weaknesses of the bus system in question?

3.3. CLASSIFICATION OF FIELDBUSES BASED ON PROPERTIES

Fieldbuses can be subdivided into two groups based on properties such as component number or restrictions in terms of configuration options: • Networking of complex devices at field and control level such as robot controllers • Connection of simple actuators and sensors such as tempera- ture sensors or limit switches

These “fieldbus types” are also often used in combination.

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