Overview of Fieldbus

Fieldbus is a kind of network system by which signal communications between field devices operating in a factory (sensors, actuators, Robot Controllers, etc.) and Controllers (PLC or Robot Controllers) are carried out using serial communications. Compared to transmissions that use analog signals, a fieldbus has the following characteristics:

Access to signals from multiple devices and multiple data from a single device using one cable.

Precise signal transmission since there is no need for A/D and D/A conversion.

Several dozen (or even a hundred) devices can be connected to one fieldbus, lowering wiring costs while making signal relay boards unnecessary. You can save the cost of relay boards and recover the space where they are installed.

More flexible modification and expansion of a system because multiple devices are simply added to one fieldbus without additional wiring.

Slave devices can transmit self-diagnostic information.

Sample Parallel Connection

Symbol	Description
a	Master Device
b	RS-232c

Sample Fieldbus Connection

Symbol	Description
a	Master Device
b	Fieldbus