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Engineering Process Fieldbus Installations

The fieldbus infrastructure constitutes the backbone of your automation system. Design rules apply analogous to any electrical installation. The following engineering criteria are important for reliability and cost-effectiveness:

Topology and components—simplicity for engineering and handling

A segment is a single circuit with power supply, fieldbus junction boxes, and instruments. The segment connects the control system to multiple instruments. The topology design determines the physical location and connection of power supplies, fieldbus junction boxes, and instruments.

The typical topology for a segment is the trunk-and-spur topology with a main line or master cable (trunk). The trunk connects the power supplies and communication interfaces located in the control room with the field. One or more fieldbus junction boxes mounted where they are easily accessible provides connections for field devices. The connection cable with a length of up to 120 m is called a spur, as it is typically much shorter in comparison to the trunk. This topology fits practically all process plants.

With its many similarities to the topologies known from multi-core trunk cables leading to a fieldbus junction box installed in the field, the trunk-and-spur​ topology is easy to understand, engineer, and maintain.

Trunk-and-spur topology provides simplicity by design. Each device is connected separately.

The fieldbus junction box is also called the device coupler. Where it is required, ignition protection is scalable through a selection of power supplies and device couplers. This enables economic solutions for any hazardous area. 

Function and availability

Modern-day device couplers provide reliable protection from typical working conditions such as device exchange, contact bounce, water ingress or power surges, etc. These functions are described in detail here 

FieldConnex simplifies engineering and implementation of fieldbus installations for any process plant in any industry with selections and options for protection from ambient conditions, and for the right availability.

See all fieldbus components for use in non-explosion hazardous areas and find the right components for your plant here


Fieldbus in hazardous areas

Fieldbus in hazardous areas requires an infrastructure with ignition protection. See below the topology for any hazardous area: Read the details on methods of ignition protection here …

Identical topology with trunk and spurs for any hazardous area. Selecting the components and installation methods provides ignition protection.


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From decisions to planning, installation, and commissioning up to operation and maintenance: Discover how to make the most out of your fieldbus infrastructure …