外文翻譯--一種新的可燃氣體報警系統(tǒng)的設(shè)計與實現(xiàn)(文件)
【正文】 tion, setting function etc. the main controller mainly includes CAN munication module, HMI, printer module, memory module, alarm module, power module etc. A inch intelligent color LCD display terminal which municate with MCU based on RS232 is used as HMI. It is easy and attractive to program, and plex interface is easier to realized. UPA16PZ miniprinter which connects with Atmega128 based on parallel port can print historical alarming record, fault record, turning off and opening records. The main controller extends 32KB E2PROM to record historical and system parameters and 32KB SDRAM to record realtime concentration information. Power module’s functions are to convert voltage and detect mercial power, backup power and charging status.III. HARDWARE DESIGN OF THE GAS ALARM SYSTEMA. Main Controller Part The circuit of the main controller mainly includes two parts: power circuit, microcontroller and various I/O modules. The power circuit mainly realizes two functions: convert 24V to 5V based on LM2575 switching voltage regulator。s very suitable to used in CAN/485 converter. Converter mainly used to convert data format between CAN and RS485. The circuit mainly includes CAN part and RS485 CAN part is similar to the part in the main controller showed in . The RS485 bus part is showed. LowPower and high performanceprice ratio chip SN65HVD3082 is used as the RS485 transceiver. Its features show as follow:1） Meets or exceeds the requirements of the TIA/EIA?485A standard.2） Low quiescent power: mA active mode and 1 nA shutdown mode.3） 1/8 unit load—up to 256 nodes on a bus. In order to enhance system stability, 6N137 is used to separate circuit and magnetic beads and lightning protection devices are added to the circuit.IV. SOFTWARE DESIGN Design of the Main Controller Program flow of the main controller is described. Before running into the main loop program, the microcontroller and other chips must be initialized and the startup interface displays for 1 minute. In this process the system detects power state, key value and reads parameters. The system parameters mainly include using condition of nodes, password and other information. Multihost munication method may be used on CAN bus, but the main controller is still used as host for estimating faults and maintaining balance of each node. The system can work stably and quickly as soon as proper error handling method is taken. The main function of key value detection and processing part is to detect weather the touch screen is pushed and then respond it. Touchscreen images mainly include three pulldown menus: displaying menu, setting menu and control menu. Each menu has several pulldown options and all the functions are pleted by key value handling function. Interruption INT0 is used to receive data from CAN bus and 29 bits extended frame format is used to send and receive messages. Register TXBnSIDH is used as node39。t receive mands from the main controller. is program flow chart of CAN/
畢業(yè)設(shè)計相關(guān)推薦
鄂ICP備17016276號-1