Modbus TCP communication protocol
[1] Introduction to the Modbus TCP protocol
In 1996, Schneider launched the Modbus protocol based on Ethernet TCP IP: modbustcp.
Modbus TCP enables the Modbus RTU protocol to run over Ethernet, and Modbus TCP uses TCP IP Ethernet to transmit Modbus packets between sites, combining the Ethernet physical network and the network standard TCP IP with Modbus as the application protocol standard for data representation. The Modbus TCP communication packet is stored in an Ethernet TCP IP packet. Unlike the traditional serial port mode, a standard Modbus TCP packet is inserted into the TCP packet and no longer has a data checksum address.
To put it simply, the ModbusQ TCP protocol is a variant of the Modbus protocol based on the TCP P network, which encapsulates the Modbus protocol in the TCP protocol stack and uses Ethernet as the physical layer to achieve communication between devices through TCP connections. [2] The Modbus TCP protocol has the following characteristics:
Connection-oriented:The Modbus TCP protocol uses a TCP connection to ensure reliable data transmission. Before you can communicate, you need to establish a TCP connection and close the connection after the communication ends
Peer-to-peer communication:The Modbus TCP protocol supports peer-to-peer communication, i.e., one-to-one communication. Each Modbus TCP device has a unique IP address that can be used to communicate directly with a specific device.
Data Types and Data Structures:Modbus TCP supports a variety of data types, including integers, floating-point numbers, booleans, and more. At the same time, it also supports a variety of data structures, such as multiple registers and bit registers for a single register.
Flexibility and scalability:The Modbus TCP protocol uses Ethernet as the physical layer, which can connect multiple devices into a network over a large network, which makes it highly flexible and scalable, and can easily add or remove devices. Ease of use: The Modbus TCP protocol is in a simple Pa format that is easy to implement and use. It is widely used in the industrial field, and the communication between devices is very convenient.
Modbus TCP protocol is widely used in industrial automation, building automation, energy management and other fields, it is a reliable and efficient communication protocol, which can realize data exchange and control between devices.
Related testimonials
The following is a brief introduction to several power meters that are widely used in the industrial and commercial fields and support the Modbus TCP protocol.
[1] ACR220ELH CE Network Multifunctional Power Meter
ACR network power meters can measure all common power parameters, such as three-phase current, voltage, active and reactive power, electricity, harmonics, etc. The ACR220ELH is configurable with Ethernet (Modbus-TCP protocol) functionalityIt is very suitable for real-time power monitoring systems.
2] APM8xx MCE Power Parameter Measuring Instrument
The APM series network power meter is designed according to IEC standards, with full power measurement, power statistics, power quality analysis and network communication functions, mainly used for comprehensive monitoring of power supply quality of power grid. This series of instruments adopts a modular design, with a feature-rich external DI DO module, an AI AO module, an SD expansion card event recording (SOE) module, and a network communication module (Among them, the MCE module supports 1 Ethernet network and supports MODBUS-TCP, HTTP, SMTP, DHCP protocolsIt can flexibly realize the full power measurement and switching status monitoring of the electrical circuit, and the dual RS485 and Ethernet interfaces can realize the data CC of the RS485 master station, eliminating the need for data switches.
[3] APM5xx CE network power meter
The APM5 series network power meter is designed according to IEC international standards, and has the functions of full power measurement, power statistics, power quality analysis (including harmonics, interharmonics, and flicker), fault recording functions (including voltage swelling and sag interruptions, inrush currents, etc.), event recording functions and network communication, etc., which are mainly used for comprehensive monitoring of power supply quality of power grid. This series of instruments is equipped with a rich function of DI DO module, AO module, wireless communication module, leakage temperature measurement module, which can flexibly realize the full power measurement of the electrical circuit and the monitoring of the switching status. Among them, the APM510 CE (cut-out size 67x67mm) and APM520 CE (cut-out size 88x88mm) support Ethernet communication Modbus-TCP protocol.
[4] ADF400L multi-user energy meter
The ADF400L series of multi-user energy meters can realize 12 three-phase or 36-channel single-phase direct access measurement or 12 channels of triple transformer access measurement, direct access and a hybrid measurement mode of transformer access through module combination. Among them, the commonly used ADF400L-1S-CE (supports 1 channel of 80A current direct access) and ADF400L-2H-CE (supports 2 channels of direct access through the transformer) have 1 channel of Ethernet communication (CE function).
[5] ACR10R-E4S CE DIN rail type three-phase energy meter
The ACR10R rail-mounted three-phase electric energy meter is suitable for energy-saving renovation projects in high-energy-consuming industries such as smelting, steel, electric welding, semiconductors, etc., as well as power monitoring and power demand-side management of distributed photovoltaic grid-connected cabinets. Integrated measurement of power parameters (such as single-phase or three-phase current, voltage, active power, reactive power, apparent power, frequency, power factor, etc.), multi-rate energy metering, four-quadrant energy metering, and power monitoring and assessment management. At the same time, it has a variety of peripheral interface functions for users to choose: with RS485 communication interface, Ethernet interface (Modbus-TCP protocol is supported) and RJ45 interface, using Modbus-RTU protocol to meet the needs of communication network management;With switching input and relay output, the functions of "remote signaling" and "remote control" of circuit breaker switch can be realized. 
About the author: Lei Shengbiao, male, currently working in Ankerui Electric Co., Ltd., mainly engaged in the research and development and application of substation operation and maintenance cloud platform system.