PROFIBUS and PROFINET

Introduction

Profibus and Profinet were created and designed by the same organization. Profibus stands for Process Field Bus and Profinet stands for Process Field Net. 

Since both were created by the same organization, they are similar in design and engineering concepts to define the hardware of each device. Thus, a user benefits in moving from Profibus to Profinet due to the similarity in engineering, design and implementation.

Profibus is a serial protocol, while Profinet is an Ethernet-based protocol. Profinet is an advanced version of Profibus, as it works on an Ethernet-based protocol and provides more speed, more bandwidth and larger message size than Profibus. Profibus lacks authentication and allows spoofed nodes to impersonate master nodes.

Let’s discuss each protocol in detail.

Profibus

Profibus is a fieldbus communication standard for automation technology. It was promoted in 1989 by the German Department of Education and Research and first used by Siemens. It is a serial communication protocol using RS-485 cable or optical fiber.

There are two variants of Profibus: Profibus DP and Profibus PA. Profibus DP is widely used as compared to Profibus PA. This is because Profibus PA is application-specific, while Profibus DP is used for general purpose.

Profibus PA stands for Process Automation and is widely used to monitor measuring equipment. Profibus DP stands for Decentralized Periphery and is also used to monitor measuring equipment. Profibus DP itself has three variants: Profibus DP-V0, DP-V1 and DP-V2.

Profibus is a master-slave protocol in which master devices control slaves for transferring data between two or more slaves. It also supports multiple master nodes, and this is managed through the use of token-sharing. 

Once the master has control of the token, it can communicate with its slaves. Slaves can also initiate communications to the master or other slaves under certain conditions. (Read more...)