What is a distributed I/O device

Application area 

When building a system, it is usually necessary to integrate the input and output of the process into the automation system.

If the input and output are far away from the programmable controller, it will need to lay a long cable, which is not easy to achieve, and may reduce the reliability due to electromagnetic interference.

Distributed I/O devices are the ideal solution for such systems:

The control CPU is in the central position

I/O devices (input and output) operate locally and distributed.

The powerful PROFIBUS DP has the ability of high-speed data transmission, which can ensure the stable and smooth communication between the control CPU and I/O equipment.

What is PROFIBUS DP?

PROFIBUS DP is an open bus system, which conforms to the standard IEC 61784-1:2002 Ed1 CP 3/1 and the Chinese national standard GB/T20540-2006, and uses the transmission protocol "DP" (DP is the abbreviation of the German term "dezentrale Peripherie" [distributed I/O]).

Physically, PROFIBUS DP is an electrical network based on shielded double wire (RS 485) or an optical network based on optical fiber cable (FOC).

The transmission protocol "DP" enables fast, cyclic data exchange between the control CPU and distributed I/O.

What are DP master and DP slave?

The DP master station is the connection between the control CPU and the distributed I/O. DP master station exchanges data with distributed I/O through PROFIBUS DP and monitors PROFIBUS DP.

Distributed I/O (i.e. DP slave station) is responsible for preparing encoder and actuator data on site, so that the data can be sent to the control CPU through PROFIBUS DP.

Which devices can be connected to PROFIBUS DP?

Most devices can be connected to PROFIBUS DP as DP master or DP slave. The only limitation is that their behavior must comply with the standard IEC 61784-1:2002Ed1 CP 3/1.