COPYRIGHT 2001-2024 © HOOHA WIRE&CABLE PRODUCTS ALL RIGHTS RESERVED.
The LIN bus is a low-cost serial communication network defined for automotive distributed electronic systems. It complements other automotive multi-path networks such as controller area networks (CAN), and is suitable for network bandwidth and performance. There is no overly demanding application of fault-tolerant features. The LIN bus is based on the SCI (UART) data format and uses the single-master/multi-slave mode, which is a special case in the UART.
LIN bus working principle
The control unit controlled by the LIN bus is generally distributed in a space with a short distance, the transmission data is a single line, and the data line can reach a maximum length of 40m. Configure a 1kΩ resistor in the master node to terminate the 12V supply, and configure a 30kΩ resistor to terminate the 12V supply from the node. Each node supplies power to the bus through the positive terminal of the battery. Each node can pull down the bus voltage through the internal transmitter.
Main control unit
The LIN master control unit is connected to the CAN data bus, monitors the data transfer process and data transfer rate, sends message headers, determines when to send information to the LIN data bus, how many times, LIN control unit in the LIN data bus system and CAN The bus directly acts as a "translation", enabling the self-diagnosis of the LIN master control unit and the connected LIN slave control unit.
Information structure of the main control unit
The main control unit of the LIN master control unit sends a message header through the LIN bus master unit at the beginning of each piece of information on the control bus conductor. It consists of a synchronization phase, and the back part is the identifier byte, which can transmit 2, 4 and 8 Byte data. The identifier is used to determine whether the master unit will transmit data to the slave control unit. The information segment contains the information sent to the slave control unit. The check area provides good security for data transmission. The check area is composed of data bytes from the main control unit and is located at the end of the message. The LIN bus master control unit transmits the current information in a cyclical fashion.
LIN slave control unit
In the LIN data bus system, the communication of the LIN slave control unit is completely controlled by the LIN master control unit. Only when the LIN master control unit issues a command, the LIN slave control unit can perform data transmission through the LIN bus. The individual control units, sensors, and actuators are equivalent to the LIN slave control unit. The sensor is a signal input device. An electronic control device is integrated in the sensor. It analyzes the measured values. The analyzed values are used as digital signals via the LIN bus. For transmission. Some sensors or actuators only use a pin on the LIN main control unit socket to transmit information, ie single-line transmission.
The LIN actuators are all smart electronic or electro-mechanical components that receive the LIN digital signal from the LIN master control unit. The LIN master control unit obtains the actual operating state of the actuator through the integrated sensor and then compares the specified state with the actual state and issues the corresponding control command. After the LIN master control unit issues a control command, the sensors and actuators can react. The LIN slave control unit waits for instructions from the master control unit and communicates with the master control unit as needed. If you want to end the sleep mode, the LIN slave control unit can send the wake-up signal itself. The LIN master control unit is installed on the LIN bus system device.
