Study And Development Of Portable Intelligent Detection Terminal For Digital Granaries

The security storage of grain is a problem for the national economy and the people’s livelihood, which is of great significance for a country. In order to make sure the security storage of grain, the measurement and control systems of stored-grain condition have been widely used. With the help of these systems, granary administrators can grasp the condition of stored-grain in time. Once any abnormal status occurs, they can take corresponding actions to reduce losses to the minimum immediately. Through extensive investigation, as there are some common disadvantages, such as over-reliance on computer terminals, network complexity, diagnosis difficulties and high cost among grain monitoring system, the portable detection terminal is entering into the stage of applications in the monitoring and control.For the problems existing in current portable detection terminal, such as simple function, single sampling, slow processing speed, poor interface display, and so on, combining with ARM embedded technology, wireless communication technology and data fault-tolerant technology, a kind of portable intelligent detection terminal for digital granaries is studied and developed in this thesis. The portable intelligent detection terminal is composed of data storage and management, touch-screen display, data acquisition function, and the main achievements summarizes as follows:(1) For the problem, that is the address codes of often lose due to the outside interference, based on the coding function of temperature cables, a online error detection and correction method is proposed in this thesis provides. After the actual test in the field, this method can diagnose and eliminate the cable fault type and ensure the effective use of cable.(2) For the problems of packet loss, repetition and sequence loss in wireless RF module communications, combining with the technology of CRC verification and timeout retransmission, an expanded protocol for communication at application layer is designed in this thesis.. After the actual test in the field, the protocol can enhance the stability of wireless communication, greatly reduce the packet loss rate, and eliminate the phenomenon of data duplication and disorder.(3)By the transplantation of μC/OS-Ⅲ operating system and μC/GUI graphical user interface system, combing with STM32 firmware library, a touch-screen display module is designed in thesis, which can provide abundant operating functions, and the man-machine interaction more convenient and quick.(4) The portable detection terminal can realize the two data acquisition mode, that are the wired data acquisition mode and the wireless data acquisition mode. The wired acquisition mode can achieve 8 channels of temperature sensor and 2 channels of humidity sensor data acquisition. The wireless acquisition mode can achieve 16 channels of temperature sensor and 2 channels of humidity sensor data acquisition, that is got from the sensor nodes connected to the extensions in grain monitoring system and capture granaries data, and through the communication of wireless RF modules.The portable intelligent detection terminal, which is Studied and developed in this thesis, not only overcomes the deficiencies of existing similar products, but also improves the flexibility of the measure and control, and is as a useful complement for measurement and control system for condition of stored-grain. Currently, this terminal has been applying in the digital granaries. Amount of results from field tests show that, all the functions are normal and stable, this terminal can improve management efficiency effectively and has very important application value for the safe storage of grain.