Low Temperature Storage Of Intelligent Control Research And Implementation

Low temperature grain storage intelligent control technology with artificialintelligence, automation and control technology, by controlling the temperature of thegrain storage to delay the aging phenomenon of food which caused by respiration ofthemselves, and to inhibit without chemicals the development and propagation ofmicroorganisms and storage pests hiding in grain, the green grain storage is anautomatic control technology with making storage quality of grain remainedunchanged in long storage, and grain storage temperature is always maintained underlow temperature.At present, the low-temperature grain storage has three methods, which wereNatural low temperature storage, mechanical ventilation with winter natural source ofcold and mechanical refrigeration used cereal cooling machine. But grain storagecould be able to establish control systems carry on automatic control only have twomethods of mechanical ventilation and mechanical refrigeration in stored grain. Thispaper broke the previous single mechanical ventilation and combine with twomethods of low-temperature grain storage technology of mechanical ventilation andmechanical refrigeration. Under the premise of the warehouse has some of the heatinsulation for cold for different of geography and climate conditions, real-timemonitoring and control storage conditions of low-temperature, to keep the storedgrain ecosystem stability below the critical temperature, realize safe grain storage,slow aging of grain quality, and increase the benefit of low-temperature storage.According different climate choose different forms of ventilation to reduce energyconsumption purpose.The design of low-temperature grain storage intelligent control system hasmainly part of the Grain monitor, expert analysis and automatic control. This paperanalyses the overall control system structure, and contrast the advantages anddisadvantages of various field bus, selecting PFROFIBUS structure, and byPROFIBUS-DP bus to connect master and slave of S7-300PLC, and elaborate howto implement the PFROFIBUS master-slave data exchange. To monitor the runningof whole control system, we installed in the host computer with configuration software in the control room, develop system control interface real-time monitor theoperating status of the intelligent control system of low-temperature grain storage. Atthe same time in the upper computer design expert system, processing temperatureand humidity information in the database by collected, to establish an expert systemlow temperature storage knowledge base and inference machine, and using inferencemachine reasoning to knowledge rules, and obtain type conclusion of the ventilation,realize the intellectualized control algorithm. Through the analysis of the granary temperature humidity to establish low temperature storage article intelligentventilated condition table, again according to the condition table design the controlprocess, using the STEP-7software program flow design, realize automatic controlfunction use of PLC. Because of the grain cooling machine and mechanical ventilatorexistence is not high control precision dynamic response slow shortcomings, thispaper through the control algorithm design and improve the performanceimprovement.