Profibus Principle

PROFIBUS is an open, vendor-independent protocol that became part of the international standard IEC 61158 in 2000. Though the protocol is mature, it certainly is not static!

Over time, it has been extended into new application areas by working groups of employees from companies that have similar products and target application areas. These extensions have always been developed under the requirement that they ensure “backward compatibility.”

Profibus Principle

PROFIBUS DP is a network that is made up of two types of devices connected to the bus: master devices and slave devices. It is a bi-directional network, meaning that one device, a master, sends a request to a slave, and the slave responds to that request. Thus, bus contention is not a problem because only one master can control the bus at any time, and a slave device must respond immediately to a request from a master.

Since a request from a master to a slave device is heard by all devices attached to the bus, some mechanism must exist for a slave device to recognize that a message is designated for it and then respond to the sender. Hence, each device on a PROFIBUS network must have an assigned address.

For specifying the address, most devices have either rotary switches (decimal or hexadecimal) or DIP switches. Some few devices require that their address be set across the bus using a configuration tool.

Profibus Guide.pdf (610.5 KB)

Excellent summary of Profibus network