When it comes to industrial networking, there are many specifications that govern the smooth exchange of information across hosts, slaves and throughout the network. All of these may be familiar with people who have mastered the art of network communication, but anyone who is starting out could be easily confused between the technical terms and accessories.
One such commonly confused pair of technical terms is the RS485 and Profibus.
Now people who do have a fair idea about the whole data exchange system in industrial networking would know that these are two very important contributors for smooth process automation. But, from a more detailed perspective, these are two different aspects related to the same concept.
Let’s get in to what each of these is.
Profibus stands for Process Field Bus. It is basically a standard of fieldbus communication used in automation technology. And field bus refers to the network protocols used for real-time distributed control.
There are two versions of the standard being used in industries. One of them is Profibus DP which stands for Decentralised Peripherals and the other is Profibus PA which stands for Process Automation. Out of these the Profibus DP is more commonly used by industries while the Profibus PA is more application specific and is hence lesser used.
Profibus DP is meant to be used to control and operate sensors and actuators through a centralized platform for automation applications in production industries and factories. It includes diagnostic options as well.
Profibus PA on the other hand is mainly used to monitor measuring equipment through a process control system of course. It is specifically meant to be used in explosion prone or hazardous areas.
The RS485 is also a standard, but it defines the electrical signal levels in the communication between drivers and receivers or hosts and slaves in networking. In this case though, the electrical signalling is more balanced and multi point systems are also supported. For the same reason, the RS485 is a very useful and popular standard in industrial control systems. It is more so as it is capable of being connected with multiple receivers, whether in a linear or a multi drop bus and it supports both Local Area Networks as well as multi drop communication links and works with data rates up to 10 Mbits.
Difference between Profibus and RS485
Both the Profibus and the RS485 are standards used in communication during process automation. However, they are used in different aspects of communication.
Profibus is a very flexible and reliable communication technology where issues can be caused by small and simple errors. On the other hand, RS485 is a more balanced technology that makes use of a two-wire transmission system. In effect this makes it the difference in voltage between the two wires among which the communication or data exchange is happening. For the same reason that it doesn’t depend on the voltage directed to the ground, it is more stable. This also makes it less sensitive to interference when compared to a single-ended transmission.