Fieldbus technology is the basis of the next generation of process control. It is an all digital, serial, two-way communication system that interconnects devices in the field such as sensors, actuators and controllers. Fieldbus is a Local Area Network (LAN) for instruments, with built-in capability to distribute a control application across the network. It has the ability to distribute control among intelligent field devices in the plant and digitally communicate that information at high speed.
With full use of field intelligence, process management is no longer just process control. It is now also asset management: gathering and using a wealth of new information from intelligent transmitters, valves and analyzers. It includes configuring, calibrating, monitoring, performing diagnostics, and maintaining records from anywhere in the plant — while the process is running.
The fieldbus can be used for control applications such as temperature, level and flow control. Devices can be powered directly from the fieldbus and operate on wiring that was previously used for 4-20mA devices. The fieldbus can also support intrinsically safe (I.S.) fieldbuses with bus powered devices. An I.S. barrier is placed between the power supply in the safe area and I.S. device in the hazardous area.