Development and Experiment of Cold Resistance Tester for Grape Roots and Branches
|School||Shandong Agricultural University|
|Course||Agricultural Electrification and Automation|
|Keywords||grape MCU sensor cold-resistance|
With the rapid development of wine industry in our country, wine brewing cultivation moves to the west and north on a large scale. The cold and droughty weather of northern winter frequently causes the frost even death of dormant grape plants. There exist obvious differences among different grape varieties, breeds and cold-resistance of organs. In particular, the cold-resistance of roots is the weakest. Therefore, choosing comparatively improved cold-resistant breeds becomes an important task of scientific workers. In order to accurately and conveniently measure the cold-resistance of grapes, it is necessary to develop a tester to measure the cold-resistance of grape roots and branches in the lab oratory. The instrument is mainly composed of not processing system, signal amplification system, collection system and host computer system.The microprocessor system is composed of STM32single chip microcomputer. STM32microcontroller using high performance ARM Cortex-M3kernel, clock frequency is72MHz, abundant I/O ports and enhanced peripheral. It Includes3general16bit timer and112bit ADC, communication interface also contains a standard:2SPI,2I2C and3USART resource module. Real-time display and with a3.2inch TFT true color.Signal amplification system mainly by the temperature transducer SBWR and a voltage transducer TM1630CP is composed of two parts. In order to exothermic temperature point can accurately determine the grape root and branch, the measurement accuracy is0.1%, the whole temperature range of absolute error was0.1℃rail temperature transmitter, The transmitter is composed of linear unit, a correction circuit, amplifying unit, a reverse protection circuit and a voltage adjusting unit etc.. The measurement of the temperature range of-40℃～60℃, the corresponding output voltage of1～5V. Due to the exothermic root and branch is very small (about1～5mV), and the thermoelectric module output is negative, so the input is0～10MV, the output is0～+5V TM_CP series isolation amplifier. TM1630CP amplifier with good linearity, high precision, using the advantages of simplicity, small temperature drift, gain range is1～1000times.A/D acquisition system is to acquire data from the transmitter, and sends the data to the MCU system, the module chooses24, height ADS8344integrated ADC chip. The ADS8344 input voltage is24V, the output voltage is0～5V, and8channels can sample the data of the8groups, the internal integration of a chopper stabilization, low input current instrumentation amplifier and a programmable gain amplifier.Microsoft Visual C++6.0development environment and C++programming language design using computer system, through the serial port to realize the communication with the lower machine. Computer use can choose serial port access and display real-time temperature-voltage curve and data values. And the measured voltage and temperature values stored in the excel table, convenient after the experiment data processing.The instrument accuracy reached0.96%, through the single-chip microcomputer control temperature sensor for real-time measurement and control the temperature in the box, the thermoelectric module determination of heat release of root and shoot tissue cells freezes, and the measured data through the serial port to send to the single chip microcomputer, after processing by the roots and branches semi-lethal temperature, finally by the host computer system display test the results and data storage. For this experimental study on cold resistance of six different varieties of grape root and branch.Experimental results show that, in the trial of six grape varieties of glorious River and Vidal root cold resistance is strong, the semilethal low temperature below-6.0℃; the strongest cold hardiness of glorious river branches, half lethal low temperature is-28.1～-30.7℃. The instrument is stable and reliable, fully meet the test requirements.