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The intelligent meal selling system is an intelligent system based on computer technology, radio frequency card technology and network communication technology. It adoptssmart card(Now mostly IC cards or ID cards, magnetic cards have been basically eliminated due to their low security) As a means of payment for catering expenses, it has fast and convenient payment (unlike cash, which requires change), and can effectively guarantee food Hygiene (unlike meal tickets or cash, which are constantly circulating in the hands of staff and diners, hiding hidden health and safety hazards) and effective financial security (money receipts and expenditures are managed by the financial center server, eliminating the corruption of related personnel Withhold). The staff canteens of current enterprises and institutions are basically equipped with intelligent meal selling systems.
The rice selling system is generally divided into bus type rice selling system and network type rice selling system according to the networking mode. Among them, the bus type rice selling system generally uses the RS-485 bus as the communication means, while the network type rice selling system is based on Ethernet. Perform data communication. Since the network-type meal selling system is based on Ethernet communication, it can directly use the ready-made local area network to realize communication. If the site has a network environment, it can connect and communicate without any wiring, which can save wiring costs. However, if the site does not have a network environment, And because the RS-485 bus wiring is simple and convenient, and its communication distance can reach 1200 meters without increasing the relay, it may be more advantageous to adopt the bus-type meal selling system.
A factory electronically transformed the staff canteens and installed them in all canteensIntelligent rice selling system, Use IC card swiping method to pay for meals, which is used to replace the original cash payment method for meal tickets, ensure food hygiene and safety in the factory, and speed up the speed of meals. Due to the large area of the factory and the relatively scattered workshops, there are many employees in the factory. There are multiple canteens scattered in all corners of the factory. Employees move around in the factory. Usually, they will eat in the nearby canteen during meal times. The original meal ticket or Cash payment can be arbitrary, but if the meal selling system of each canteen cannot be managed uniformly on the Internet, employees can only eat in the designated canteen, which is very detrimental to the management of the factory.
The construction party initially hoped to adopt a network-type meal selling system, using TCP/IP network to connect the meal vending machines in each canteen and the computer in the financial center for communication. During the project evaluation process, it was found that the factory does not have office automation like office buildings. The needs of the company require the construction of a local area network. There is no network environment inside the factory. If the network is based on a TCP/IP network, a local area network needs to be built in the factory area. The project is very large and there is not much necessary. The factory cannot accept just A plan to build a local area network in the factory for the rice sales system.
The construction party only adopts the bus type meal selling system, which uses the RS-485 bus as the communication line to network the meal selling systems of each canteen. The transmission distance can reach 1200 meters. The maximum communication distance can be achieved by adding a 485 repeater. Reach over 6000 meters. The RS-485 bus is relatively simple and convenient for wiring, and the cost is relatively lower than that of building a local area network. However, due to the large area of the factory, the number of wires consumed is also very large, and the cost is also very high, which is unbearable for the factory.
After full communication with the factory, it was discovered that due to the factory’s construction of a video surveillance system in the factory area at the front end, optical cables were placed around the wall of the factory area to connect to the video optical transceivers at the edge of the factory area. Because redundancy was considered at the time, there were redundant optical fibers in the optical cable. , The construction party decided to use the optical fiber line to transmit the bus data signal and connect it to the network through the optical fiber line. The optical fiber modem of Shenzhen Guokeweiye Communication Technology Co., Ltd. is used to realize the two-way conversion between RS-485 bus and single-mode optical fiber, and realize the two-way conversion between 485 serial port signal and optical fiber signal. A ring network type N-271 fiber optic modem is used here, which uses a ring network connection method for one-master and multiple-slave connections. The specific connection methods are as follows:
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