3-4. PLC 통신 종류

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
16. MECHATROLINK
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

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, the standard communication protocols are used.

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

#	Protocol/Cable	Baud Rate	Length	Node
01	Ethernet	100 Mb/s	(Few Km)	255
02	Profibus	5-12 Mb/s	15 Km	127
03	MPI	19.2- 38.4 Kb/s	50 m	32
04	PPI	187.5 Kb/s	500 m	1
05	DH	230.4 Kb/s	3.048 Km	64
06	Control Net	5 Mb/s	30 Km
07	Device Net	500 Kb/s	0.487	64
08	USB Adapter	57.6 Kb/s	10 m	1
09	PC Adapter	9600 Kb/s	15 m	1
10	RS-232	19.2 Kb/s	10 m	1
11	RS-485	10 Kb/s	1.2 Km	32

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. 
• 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.

 

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