Computers and instruments are needed to connect in single network in a manufacturing plant, so that the sensing and real time control is possible. This connecting network is known as Field bus. A field bus network bus allow an industry working smoothly.
A simple field bus is shown above, which consist of mainly four levels.
Level 1 : sensor bus network
Level 2 : Device bus network
Level 3 : Control bus network
Level 4 : Enterprise level network or information level network.
As the level increases the the level of complexity increases.
Sensor bus Network:
This level includes all the basic field devices , which mean all the sensors and controller outputs in an unit. All the sensors are connected to one network cable, same as the controller output devices.
Device bus network:
Just as like the sensor bus network but large in size, work in large scale. All the Sensor bus Network are connected to this network. Variable speed drives and motor control centers are connected to them to have control over individual elements.
Control bus network:
Control bus network is where high level data communication happens. The controllers like PLCs are connected to each other anlong side HMI( Human Machine Interface) for the complete control on the network.
Enterprise level network:
Most complex level in network, here all computers and departments are inter- connected together. this computer driven level allows data monitoring, file management, file transfer in a large scale etc,.