基于PLC的马铃薯水肥一体化精准混肥系统设计

针对当前我国大田马铃薯水肥一体化灌溉系统混肥和检测不精确、没有具体针对马铃薯作物、智能化程度低等问题，设计研发了一款基于PLC、物联网控制的精确控制水肥一体化系统。由于大田马铃薯生长环境差、不稳定因素多，该系统使用PLC控制。相比较单片机的控制方式，PLC具有可靠性高、抗干扰能力强、编程简单方便、恶劣工作环境适应性强和施工方便等很多优点。由于传统大田水肥机利用增压泵将文丘里吸肥器吸取的肥料直接注入主管道利用水流冲刷自然混肥，无法保证混肥的精准性，EC、pH传感器也无法精准测量，导致田间作物肥料浓度无法保证一致，作物质量及产量相对较低。相比传统水肥机，增加混肥腔混肥能够明显降低水肥浓度误差。EC、pH传感器实时读取当前的水肥浓度及酸碱度，与预设值做PID运算，再将PID输出通过线性转换转换为脉冲输出时间，通过PLC输出控制文丘里电磁阀的通断吸肥时间，实现水肥浓度的精确调整，配合恒压变频柜使水压在设定值范围内波动，实现水肥精确、稳定输出。 

PLC-based potato water and fertilizer integration precision fertilizer mixing system design

In response to the current problems of mixing fertilizer, imprecise detection, no specific for potato crops, and low degree of intelligence in China''s field potato water and fertilizer integrated irrigation system, we design and develop a water and fertilizer integrated system with precise control based on PLC and IOT control. Due to the poor growth environment of potatoes in big fields and many unstable factors, this system uses PLC control, which has many advantages such as high reliability, strong anti-interference ability, simple and convenient programming, strong adaptability to harsh industrial environments, and easy construction compared to the control method of microcontroller. As the traditional field water fertilizer machine uses the booster pump to inject the fertilizer absorbed by the venturi directly into the main channel to use the natural mixing of fertilizer by water flushing, which cannot ensure the accuracy of fertilizer mixing, and the EC and PH sensors cannot measure accurately, resulting in inconsistent fertilizer concentration of field crops and relatively low crop quality and yield; compared with the traditional water fertilizer machine, the addition of fertilizer mixing chamber can significantly reduce the error of water fertilizer concentration. / PH sensor real-time reading of the current water fertilizer concentration and pH, and preset values to do PID operation, and then the PID output through linear conversion into pulse output time, through the PLC output control venturi solenoid valve on and off fertilizer absorption time, to achieve accurate adjustment of water fertilizer concentration, with constant pressure frequency conversion cabinet so that the water pressure fluctuates within the set value, to achieve accurate and stable output of water fertilizer.