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WiFi Wireless Module VS LoRa module
WiFi Wireless Module and LoRa module are two different wireless communication technologies, and they have obvious differences and contrasts in several aspects.
Communication range:
WiFi Wireless Module: WiFi modules are usually suitable for relatively short-distance communication, and generally can cover a range of tens of meters to hundreds of meters in an indoor environment. Its transmission distance is affected by physical obstacles and signal interference.
LoRa module: LoRa module adopts low-power wide area network (LPWAN) technology, has a long communication range, can cover a range of several kilometers to tens of kilometers in an outdoor environment, and has good penetration and anti-interference capabilities.
Transmission rate:
WiFi Wireless Module: WiFi modules usually provide a higher transmission rate and can support data transmission speeds up to several hundred megabits per second. This makes WiFi suitable for applications that require the transfer of large amounts of data quickly, such as video streaming and large file transfers.
LoRa module: The transmission rate of the LoRa module is low, generally in the range of several kilobits per second to hundreds of kilobits per second. It is mainly used in IoT applications with low power consumption and more emphasis on long-range transmission and long battery life.
Power consumption and battery life:
WiFi Wireless Module: WiFi modules typically require high power consumption, which can be a burden on battery-powered devices, limiting their usage time in low-power applications.
LoRa module: LoRa module uses low power consumption technology, has excellent energy efficiency, and can run on battery power for a long time, usually up to several years of battery life.
Network topology and deployment:
WiFi Wireless Module: The WiFi module is usually used to build a local area network (LAN), and the device needs to connect to an existing WiFi network or communicate through a WiFi router. This network topology requires certain infrastructure support.
LoRa module: The LoRa module can build a low-power wide-area network (LPWAN), has the ability to self-organize the network, does not require complex infrastructure support, and can achieve wide-area coverage and long-distance communication.
According to specific application requirements, select the appropriate wireless communication technology. The WiFi Wireless Module is suitable for short-distance, high-speed transmission applications, while the LoRa module is suitable for long-distance, low-power Internet of Things applications.
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The main difference between ModBus RTU and ModBus TCP
The main difference is that Modbus RTU uses a daisy-chain network, so you can connect the entire network with two wires and communicate with each device by giving each node a unique address. ModBus TCP uses a star network where each node has a separate cable called Cat5 or Cat6. They can be connected using a router. They also carry a personal address that is unique to each node on the network. The addresses can be from 1 to 255, which means that in theory, you could have 254 devices on the same network. You can also use Modbus TCP over the Internet.
The trend in 2023 is for more field devices to use ModBus RTU, but ModBus TCP is catching up. Pressure transmitters, flow meters, and gas analyzers use Modbus RTU. PLCs, DCS, and control room equipment use Modbus TCP. Some devices that communicate with web servers over the internet are using Modbus TCP. Input and output analog and digital modules are available on ModBus RTU and ModBus TCP.
Could ModBus be a low-cost solution?
For both ModBus RTU and ModBus TCP, the answer is yes. ModBus RTU applications require a reading of 4-20mA or 0-10 V input and display in a PC or PLC. Whereas with ModBus TCP, you only need an emulated ModBus TCP card and connect it directly to a PC with a Cat5 or Cat6 cable using a crossover cable or through a router, and you can read the ModBus registers very quickly.
Whether using ModBus RTU or ModBus TCP, you will find it a simple and low-cost solution for your application. Depending on the size and complexity of the system, one can choose a protocol that better suits the user's needs, but both protocols provide excellent solutions for industrial automation applications.
MQTT protocol - design specifications, characteristics, principles
The MQTT protocol has become a hot word in the Internet of Things communication. Today, let's discuss some knowledge about the MQTT protocol.
Andy Stanford-Clark of IBM and Alan Nip of Cirrus Link wrote the first version of the protocol in 1999. In 2013, IBM submitted the MQTT version 3.1 specification to the Structured Information Standards Promotion Organization, with relevant charters to ensure that only a small number of changes can be made to the specification.
The MQTT (Message Queue Telemetry Transport) protocol is a message protocol based on the publish/subscribe paradigm under the ISO standard (ISO/IEC PRF 20922). It works on the TCP/IP protocol family and is a publish/subscribe message protocol designed for remote devices with low hardware performance and poor network conditions.
MQTT is a client-server-based message publishing/subscribing transport protocol. The MQTT protocol is lightweight, simple, open, and easy to implement. These characteristics make it widely applicable. Such as machine-to-machine (M2M) communication and the Internet of Things (IoT). They are also widely used in communicating sensors via satellite links, occasional dial-up medical devices, smart homes, and some miniaturized devices.
Due to the particularity of the IoT environment, MQTT design needs to comply with the following specifications:
① Streamlined, without adding dispensable functions;
② Publish/Subscribe (Pub/Sub) mode to facilitate message transfer between sensors;
③ Allow users to dynamically create topics, with zero operation, and maintenance costs;
④ Minimize the amount of transmission to improve transmission efficiency;
⑤ Take factors such as low bandwidth, high latency, and unstable network into consideration;
⑥ Support continuous session control;
⑦ Understand that the computing power of the client may be low;
⑧ Provide service quality management;
⑨ Assuming that the data is agnostic, the type and format of the transmitted data are not required to maintain flexibility.
features
The MQTT protocol is a protocol designed for communication between remote sensors and control devices in low-bandwidth, unreliable networks. It has the following main characteristics:
① Use the publish/subscribe message mode to provide one-to-many message publishing and decouple application programs.
② Message transmission for payload content masking.
③ Use TCP/IP to provide a network connection.
④ There are three kinds of message publishing service qualities: "at most once", "at least once" and "only once".
⑤ Small transmission, small overhead (fixed-length header is 2 bytes), protocol exchange is minimized to reduce network traffic.
⑥ Use the Last Will and Testament features to notify the relevant parties of the mechanism of abnormal client interruption.
The realization of the MQTT protocol requires the completion of communication between the client and the server. During the communication process, there are three identities in the MQTT protocol: Publisher (Publish), Broker (Server), and Subscriber (Subscribe). Among them, the publisher and subscriber of the message are clients, the message agent is the server, and the publisher of the message can be the subscriber at the same time.
The message transmitted by MQTT is divided into two parts: topic (Topic) and load (payload):
Topic, which can be understood as the type of message, after the subscriber subscribes (Subscribe), he will receive the message content (payload) of the topic;
payload, which can be understood as the content of the message, refers to the specific content that the subscriber wants to use.
An MQTT client is an application or device using the MQTT protocol that always establishes a network connection to a server. Clients can be:
(1) Publish information that other clients may subscribe to;
(2) Subscribe to messages published by other clients;
(3) Unsubscribe or delete messages from the app;
(4) Disconnect from the server.
The MQTT server is called a "message broker" (Broker), which can be an application or a device. It is located between message publishers and subscribers. It can accept network connections from customers; accept application information published by customers; process subscription and unsubscribe requests from clients; and forward application messages to subscribed customers.
Remote I/O Module is a device used to implement distributed input/output functions
Remote I/O Module (Remote I/O Module) is a device used to implement distributed input/output functions. It allows sensors, actuators and other devices to be remotely connected to a central control system for functions such as monitoring, control and data collection.
Remote IO modules usually include the following components:
Input interface: used to connect sensors or other external signal sources. These interfaces can accept digital or analog signals and convert them to digital for processing.
Output interface: used to connect actuators or other external devices. These interfaces can send digital signals or analog control Single serial port server signals to external devices for control and operation functions.
Communication interface: used to communicate with the central control system. Remote IO modules usually use various communication protocols and interfaces, such as Ethernet, serial port, wireless communication, etc., for data exchange and remote control with the control system.
Processing unit: Remote IO modules usually contain an embedded processor or microcontroller to perform tasks such as data processing, communication protocol processing, and device control.
The advantages of remote IO modules include:
Flexibility: Remote IO modules can be remotely installed in different locations and connected with the central control system. This enables the distributed layout of equipment and flexibly responds to various engineering needs.
Expansibility: Through the remote IO module, the input and output points of the system can be easily expanded to adapt to changing needs. Simply add or replace remote IO modules without changing the entire control system.
Anti-interference: Due to the long distance between the remote IO module and the sensor and actuator, CAN2.0 Communication Module the influence of electromagnetic interference on signal transmission can be reduced, and the reliability and stability of the system can be improved.
High performance: Remote IO modules are usually equipped with strong processing capabilities and communication functions, which can handle complex control algorithms and large amounts of data transmission, and provide high-performance distributed control solutions.
Remote IO modules are widely used in industrial automation, building automation, smart home and other fields, providing convenience and flexibility for system integration and control realization.
Low-power wireless communication refers to the use of wireless technologies that consume minimal energy
Low-power wireless communication refers to the use of wireless technologies that consume minimal energy during transmission and reception. This type of communication is commonly used in applications where devices have limited power sources, such as battery-powered devices or energy-harvesting systems. Low-power wireless communication enables efficient data transfer over short to moderate distances while conserving energy and extending battery life. Several wireless technologies are designed specifically for low-power applications, including:
Bluetooth Low Energy (BLE): BLE is a wireless communication standard that consumes very low power. It is commonly used in applications such as wearable devices, fitness trackers, and home automation systems. L BLE devices operate in the 2.4 GHz frequency band and offer short-range communication.
Zigbee: Zigbee is a low-power wireless technology designed for applications requiring low data rates and long battery life. It operates in the 2.4 GHz or sub-GHz frequency bands and is commonly used in smart home automation, industrial automation, and wireless sensor networks.
Z-Wave: Z-Wave is a wireless technology that focuses on low-power consumption and reliable communication in smart home applications. It operates in the sub-GHz frequency range and offers good range and penetration through walls and obstacles.
LoRaWAN: LoRaWAN (Long Range Wide Area Network) is a low-power, wide-area networking protocol that enables long-range communication while consuming minimal power. It is suitable for applications such as smart cities, agriculture, and industrial monitoring, where low data rates and long battery life are essential.
NB-IoT (Narrowband Internet of Things): NB-IoT is a low-power wide area network (LPWAN) technology that operates on licensed cellular bands. It is designed specifically for Internet of Things (IoT) applications and offers long-range communication with extended battery life.
These technologies incorporate power-saving techniques such as duty cycling, where devices alternate between active and sleep modes to conserve energy. Additionally, they employ efficient data transmission protocols and optimized hardware designs to minimize power consumption while maintaining reliable communication.