| The fresh and storage of farm products is one of the mainly contents of the new technical revolution in agriculture. It is the key segment of reprofitment from farm products. It is also the key base to the development of light industry. The posterior product loss of farm products is vast every year in our country. For example,the posterior product loss of vegetable generaly is between twenty-five percent and thirty percent. And between twenty percent and twenty-five percent to fiuit. Therefore,air county is in dire need of reinforcing the technological research of fresh and storage of form products,extending and applying the relative gain,developing energetically the industry of fresh and storage of farm products. Besides,whether our farm products can enter into the international market of farm products,stand the intense competition from the whole world,which demand that we should improve the fresh and storage of farm products. This research based on the great development of industry of controlled atmosphere cold store at present,design an automobile monitoring and controlling system used in controlled atmosphere cold storage in order to solve the low degree in automation,negative effect caused factitiously on farm products and the poor quality of fresh and storage of farm products. The monitoring and controlling system bases on the P-80C51 micro-chip. The system establishes a optimum environment in controlled atmosphere cold storage by using die way of real time monitoring and controlling. The following are the main characteristics of the system.1. Tlirough the analysis of the environment in controlled atmosphere cold storage and it's effects on farm products. It can be concluded that the key task to fresh and store of vegetable and fruits is to furthest restrain the process life activity after they are picked,postpone their transformation and extend their life span of fresh and storage. In practice,we adjust the temperature,the relative humidity and the air component in the controlled atmosphere cold storage in order to accommodate the breath intension of farm products. So the goals of fresh and storage of vegetable and Suits can be readied.2. The hardware of the system is made up of P80C51,EPROM,RAM,8155,AD0809,DA0832,8279 and so on. It can do such works:collecting analogue signals,filtering wave,using keyboard and displaying contents. It also can do the work of the transition between analogue and data. Besides,it need driving the buses because there are so many chips on the bus.3. The software of the system is design into the top software system and the low softwaresystem. At present,the work to collect data,monitor and control the environment should be realized by the low system software because the communication between the top and the low hasn't achieved successful. The top computer system's software can receive the data which the low computer sendes. At the same time,the low computer can receive some system's parameters and some controlling orders. We can save the collected data into the hard disk and analyze it by-some application software to handle data if we need it.4. The working environment of the system is often bad. And the disturbance is too much. We take some measures to prevent the emergence of disturbance when we design the hardware. For example,we increase the copper breadth according to the magnitude of the electric current. The RC circuit is used to absorb the spark generated by buttons and relays when they are putted At the same time,we use the redundancies instruction technology and the trap technology in software aspect avoiding the interference,which can assure the system work credibility.5.The temperature sensor and the relative humidity sensor in the system are all identified by the national standard facilities. The precision and the degree of sensitivity both meet the requirements. We use the software compensation method to amend the output of the sensors,which achieve satisfactory result.6. The communication of the system between the... |
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