Skip to main content

Commonly used PLC protocols

 There are several commonly used PLC protocols, including Modbus, Ethernet/IP, Profibus, DeviceNet, and CC-Link. Here is a brief comparison of these protocols:

  • Modbus: Modbus is a serial communication protocol used to connect PLCs to other devices such as sensors, instruments, and HMIs. It is a simple and reliable protocol widely used in industrial automation applications. The maximum transmission speed of Modbus is 115.2 kbps, and a single network can support up to 247 devices.
  • Ethernet/IP: Ethernet/IP is an industrial protocol based on standard Ethernet technology. It is a high-speed protocol that can transfer data at speeds of up to 100 Mbps or more. Commonly used for real-time control and monitoring applications, Ethernet/IP can support up to 64,000 nodes on a single network.
  • Profibus: Profibus is a digital communication protocol used to connect PLCs to other devices such as sensors and actuators. It is a high-speed protocol that can transfer data at speeds up to 12 Mbps. Commonly used in process automation and manufacturing applications, Profibus can support up to 126 devices on a single network.
  • DeviceNet: DeviceNet is a communication protocol used to connect PLCs to industrial equipment such as sensors, actuators and motor starters. It is a simple and reliable protocol commonly used in machine control and material handling applications. DeviceNet has a maximum transmission speed of 500 kbps and can support up to 64 devices on a single network.
  • CC-Link: CC-Link is a communication protocol used to connect PLCs to other devices such as sensors and actuators. It is a high-speed protocol that can transfer data at speeds up to 10 Mbps. Commonly used in manufacturing applications, CC-Link can support up to 64,000 devices on a single network.

Each of these PLC protocols has advantages and disadvantages, and the choice of protocol will depend on the specific application requirements. Modbus is a simple and reliable protocol widely used in industrial automation applications, while Ethernet/IP is a high-speed protocol commonly used in real-time control and monitoring applications. Profibus is a high-speed protocol commonly used in process automation and manufacturing applications, while DeviceNet is a simple and reliable protocol commonly used in machine control and material handling applications. CC-Link is a high-speed protocol commonly used in manufacturing applications that can support a large number of devices on a single network.

TCP/IP is used in some PLCs for communication with other devices over an Ethernet network. TCP/IP is a suite of protocols that provides reliable and secure communication over a network. It is widely used in industrial automation applications, including PLCs, for communication with other devices such as HMIs, SCADA systems, and other controllers.

In PLCs, TCP/IP is typically used in conjunction with Ethernet communication protocols, such as Ethernet/IP or Modbus TCP. TCP/IP provides a standardized and reliable way for devices to communicate over an Ethernet network, and it is used for a wide range of applications, including real-time control, data monitoring and logging, and remote access and control.

PLCs that support TCP/IP communication typically have an Ethernet port or module that can be used to connect to an Ethernet network. The Ethernet port or module may support a range of communication protocols, including TCP/IP, Ethernet/IP, Modbus TCP, or other proprietary protocols.

Labels:

Comments

Post a Comment

Popular posts from this blog

Ferrules and Cross Ferruling

 Ferrules are identification labels provided for every wire terminations in an instrument, equipment, or electrical/instrumentation control panels. These tube-shaped sleeves can be inserted easily on each individual wire in a multi-core cable. In earlier days fixed digits/letters are used as ferrules, but now Instrumentation engineers/technicians prints out desired ferrules by using a ferrule printing machine. Typical Ferrule The numbers/ letters on the ferrules will be given as per the approved electrical hook up or loop diagrams. This helps technicians to easily identify a particular loop/wiring from a series of terminal blocks and to troubleshoot the desired terminal connection. Separate numbers on the ferrules distinguish the positive and negative polarities of wires, thus ensure the polarity protection of the instrument. Cross Ferruling  As a wire is connected on its both ends, it is quite useful to use a cross reference method for wire identification. Unlike normal ferru...
1 comment
Read more

What is a Torbar? – Averaging Pitot Tubes

 The Torbar is employed for flow measurement of liquids, gases, or steam in circular, square, or rectangular section ducts for large flow rates. The Torbar is an insertion type multi-port self-averaging primary sensor for flow measurement. Torbar TORBAR is a set of Pitot tubes mounted on a bar across the pipeline with no moving parts. An averaging Pitot tube is a technology, while TORBAR is a manufacturing brand name. There are several brands available in the market with VERABAR, ANNUBAR, etc. Averaging Pitot Tube Principle Purpose Averaging Pitot tube can be employed when the average velocity of the flow profile, rather than the velocity in a specific point in the cross-section is desired. Averaging Pitot Tubes Principle It measures the differential pressure between the static pressure tap and the tap of full pressure of a stream. Thus such magnitude of differential pressure is directly proportional to the square of the flow rate. Working The TORBAR is designed in such a way that ...
7 comments
Read more

Dissolved Oxygen Analyzer Working Principle

 What is dissolved oxygen ? Dissolved oxygen refers to oxygen dissolved in water. Its concentration is expressed as the amount of oxygen per unit volume and the unit is mg/L. Biologically, oxygen is an essential element for respiration of underwater life and also acts as a chemical oxidizer. The solubility of oxygen in water is affected by water temperature, salinity, barometric pressure, etc. and decreases as water temperature rises. Measurement of dissolved oxygen by the membrane electrode method The membrane electrode method measures a diffusion current or reduction current generated by the concentration of dissolved oxygen or partial pressure of oxygen to obtain the concentration of dissolved oxygen. This method is not affected by the pH value of water being measured, oxidation and reduction substances, color, turbidity, etc. and the measurement method offers good reproducibility. When a sensor is inserted into water, an air layer forms on the membrane (Teflon membrane). The ox...
1 comment
Read more