Serial communication is a method used to transmit data between devices, typically by sending bits of information one after another over a single data line. This approach uses fewer wires compared to parallel communication, making it cost-effective for long-distance communication, although it generally operates at slower speeds. A serial interface is a device that converts parallel data from the CPU into a continuous stream of serial data and vice versa. The circuit responsible for this function is known as a serial interface circuit.
Serial communication is widely used in engineering applications, especially when connecting an upper computer (like a PC) with a lower computer (such as a microcontroller). In such scenarios, the lower computer often processes analog signals through an ADC and sends the digital data to the upper computer via a serial port. Conversely, the upper computer can send commands or information back to the lower computer. Common serial interfaces include RS232, RS485, and RS422, which differ mainly in their voltage levels.
RS-232 (ANSI/EIA-232 standard) is a widely used serial communication standard, primarily found in IBM-compatible PCs. It supports various applications, such as connecting peripherals like mice, printers, and modems, as well as industrial instrumentation. However, its practical use often exceeds the standard limits in terms of distance or speed due to improved cabling and drivers. Notably, RS-232 is limited to point-to-point communication and has a maximum effective range of about 50 feet.
In many projects, developers need to implement custom serial communication solutions. For example, using Java to communicate with a lower computer via RS485 involves several steps. First, download the appropriate RXTX library (either 32-bit or 64-bit depending on your system). Then, import the RXTXcomm.jar file into your project and copy the necessary DLL files (rxtxSerial.dll and rxtxParallel.dll) into the JDK and JRE bin directories.
Once the environment is set up, you can begin writing code to detect available serial ports and configure them. The process involves identifying the COM ports, setting the baud rate, and verifying whether the selected port is indeed a serial port. After configuration, data can be sent and received using Java's input and output streams.
To demonstrate this, you could create a simple application that sends the current system time to a lower computer. This involves retrieving the time, converting it into a byte array, and encapsulating it into a custom protocol packet. The packet might include a header, command identifier, data length, checksum, and a tail marker. Once the packet is ready, it can be transmitted via the serial port.
Debugging is essential during development. You can print logs at key points in the program to verify that each step is functioning correctly. Additionally, implementing a thread can allow the upper computer to continuously send time updates instead of just once. For more advanced applications, you could also store received data in a database and generate visualizations for analysis.
By following these steps, you can build a functional serial communication system between an upper and lower computer, and further enhance it by adding user interfaces, threading, and data storage features.
Earth Leakage Breaker ELCB
ELCB is an acronym for Earth leakage circuit breaker, which is a device placed inside a water heater, commonly referred to as ELCB electric leakage breaker. This circuit breaker has the function of disconnecting the device from the circuit whenever an electrical leak occurs through the human body when touching the electrical parts of the device.
ELCB is to limit the incident of electric shock inside the machine, disconnecting the power when there is a problem, ensuring safety for human life as well as fire and explosion prevention.
How many types of ELCB?
ELCB is often used in both civil and industrial applications.
For the domestic electricity system, the installation problem is not difficult, but in industry, the anti-shock for workers and the prevention of electrical leakage for electrical equipment with large capacity requires a bridge. Automatic anti-shock, high-power leakage protection, and often has a much higher price.
elcb,elcb 15ma,elcb 10ma,elcb breaker,circuit breaker,rccb,rcd residual current
ZHEJIANG QIANNA ELECTRIC CO.,LTD , https://www.traner-elec.com