Sensor Bus Networks
At the lowest level of process automation, the Sensor Bus is a low-cost way to extend the benefits of networking to simpler devices and still be able to connect with higher-level protocols using gateways.
Sensor busses focus solely on discrete devices and offer little connectivity for analog inputs.
AS-i (Actuator Sensor Interface) is the most common Sensor Bus worldwide.
Field devices typically connected to Sensor Bus Networks include on/off valves, limit switches, solenoid valves, and pressure, temperature, level, and flow switches. |
Device Bus Networks
Moving up a level in complexity, device busses provide for control of complex discrete devices and equipment power. Device Bus Networks are typically used for connectivity in areas with a high density of discrete devices, variable speed drives, and motor control centers.
The most commonly used Device Bus Networks include DeviceNet and Profibus-DP.
DeviceNet is used extensively in factory automation and is also proving useful in process automation.
Field devices typically connected to Device Bus Networks include on/off valves, motor control centers, variable frequency drives, and numerous discrete sensors and actuators. |
Process Control Networks
Process Control Networks are the most advanced fieldbus networks in use today. They provide connectivity of sophisticated process measuring and control equipment. While more complex in functionality, today’s process control networks can be easily deployed for new or existing process equipment, and today’s engineering tools allow for correct, efficient design. The advanced characteristics of the host interfaces and devices make connectivity, addressing, and commissioning much simpler than conventional devices.
FOUNDATION Fieldbus is emerging as a leader at this level, with strong market share in North America and increasing share throughout the world. Profibus PA is also a viable alternative, with particularly good acceptance in Europe.
Field devices typically connected to Process Control Networks include control valves, temperature and pressure transmitters, level measurement equipment, flow meters, process analytical instruments, and on/off valves where appropriate. |
