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Today, we are studying the most used Programmable Logic Controller (PLC) communication protocols in the industry.

This article contains the top 31 communication protocols for PLC in detail.

Firstly, you should know…

What is Communication Protocol?

We all know the typical definition of communication protocol.

The communication protocol is a set of rules that govern data communication.

In other words, the communication protocol acts as an agreement between two or more communicating devices.

By using the communication protocols, two devices connect and communicate with each other.

Without communication protocol, devices can only be connected but not communicated.

List of PLC Communication Protocols

What are networking protocols used in Industrial Automation?

Here, I am listing the different types of communication protocols used for the automation of processes in PLC.

  1. EtherNet/IP
  2. Profibus
  3. Modbus
  4. Interbus
  5. ProfiNet
  6. ControlNet
  7. DeviceNet
  8. DirectNet
  9. CompoNet
  10. RAPIENet
  11. EtherCAT
  12. MelsecNet
  13. Optomux
  14. DF-1 Protocol
  15. HostLink Protocol
  17. DH- Data Highway
  18. PPI- Point to Point
  19. EtherNet Powerlink
  20. MPI- Multi-Point Interface
  21. EGD- Ethernet Global Data
  22. AS-i- Actuator Sensor Interface
  23. OSGP- Open Smart Grid Protocol
  24. DNP3- Distributed Network Protocol
  25. SDS- Smart Distributed System Protocol
  26. PieP- Process Image Exchange Protocol
  27. SRTP- Service Request Transport Protocol
  28. BSAP- Bristol Standard Asynchronous Protocol
  29. FINS- Factory Interface Network Service Protocol
  30. HART- Highway Addressable Remote Transducer Protocol
  31. Recommended Standard (RS-232, RS- 422, and RS-485) Protocols

These are the foremost communication protocols used for the PLC and other network connections. These protocols are supported by different PLC software brands.

The communication protocols are dependent upon three fundamental parts such as baud rate, network length, and the number of nodes.

More communication protocols are available in the market. You can easily buy PLC communication protocols.

What is the Baud Rate?

Baud rate is also known as Communication speed.

The rate of data transmission on the network is called Baud Rate. The unit of Baud Rate is bits/second (b/s).

In simple terms, it is calculated as the “number of data transferred per second”.

Characteristics of PLC Communication Protocols in Table

When PLC modules are connected over the network, standard communication protocols are used.

The different types of standard communication protocols support different speeds (baud rate), distances (network length), and the number of connecting devices (nodes).

#Protocol/CableBaud RateLengthNode
01Ethernet100 Mb/s(Few Km)255
02Profibus5-12 Mb/s15 Km127
03MPI19.2- 38.4 Kb/s50 m32
04PPI187.5 Kb/s500 m1
05DH230.4 Kb/s3.048 Km64
06Control Net5 Mb/s30 Km
07Device Net500 Kb/s0.48764
08USB Adapter57.6 Kb/s10 m1
09PC Adapter9600 Kb/s15 m1
10RS-23219.2 Kb/s10 m1
11RS-48510 Kb/s 1.2 Km32

Which PLC communication protocol you should use?

  • If you want to communicate with the more number of nodes with more speed, Ethernet is the best choice. You can read detail about ethernet here.
  • If your network has a length of more than 25 Kilo-meter, you should use the Control Net protocol.

Binary Data Type Conversion for Baud Rate

Binary system based on the bit. Bit is either 0 or 1.

  • 1 Nibble= 4 Bits
  • 1 Byte= 8 Bits
  • 1 Word= 2 Bytes = 16 Bits
  • 1 Double Word= 4 Bytes= 32 Bits

Let’s see, binary data representation diagram.

This is all about topmost PLC communication protocols. And I also covered the basic fundamental parts of protocol like Baud rate (communication speed), network length, and the number of nodes supported by each protocol.

Which communication protocol do you use for PLC? Share with me by commenting below. If you have any queries, let’s discuss them.

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Happy PLC Learning!

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52 thoughts on “31 Most Used PLC Communication Protocols in Industry”

  1. Thanks for the valuable info.
    .We are using ethernet cat5 utp cable for controller communications to remote control room.

  2. Thanks for valuable information.
    you can send me some PLC questions based on timer,counter,holding ,and project based ?

  3. Please explain me that how can we select a servo motor and its drive in a machine and what are the parameters need to configure to run a servo motor with a drive .

  4. Thank you for your valuable information. Please explain to me, what is the term ‘physical medium’ using in PLC Communication? I have some doubt about the same.

    • Hi Nishida. It is physical Media, not a physical medium.

      In the PLC communication system, we are using physical media to transfer the data information from one place to another and as well for storing data. For these communication data storing and transferring, physical media refer to the physical materials in the form of conducting material.

      There are three different types of Physical media used in a communication system – 1. Copper wire, 2. Optical fiber and 3. Coaxial cable.

      If you have any queries or doubts, you can freely ask me.

  5. Nicely Explained!

    Please, explain how to link or communicate PLC with PLC?
    Which kinds of communication protocols are commonly used and how to address multiple PLCs.

  6. Thank you for your valuable information but I have still doubt in “nodes”? Can you please explain to me with a brief.

  7. Hi, thank you very much for your help, I Want to know what are the references for this table of characteristics of communication protocols.

  8. Nicely explained!

    To understand the Communication protocol your given table is very very useful.

    Thanks a lot for the Characteristic table.


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