Modular fieldbus designs and applications

One of the main benefits of the fieldbus technology is its significant reduction in wiring. This is because each process requires only one wire to be run to the main cable. Installation costs are further reduced because the fieldbus is a multi-drop rather than a point-to-point system. (The multi-drop network can offer a 5:1 reduction in field wiring expense.) A number of pneumatics manufacturers have already developed devices for various programmable logic controller (PLC) fieldbus protocols, in the form of control blocks mounted directly on to standard pneumatic valve manifolds. The next generation of modular valve manifolds has emerged too. These do not need wiring, because they are based on a virtually "plug-and-play" design and installation method. This means that with this modular design one simply selects the valve configuration needed for the process, plugs the modules together, and the manifold is ready to connect into a fieldbus network.