Abstract
This paper mainly designs the electronic draft gage, which is at core of AT89S51. Electronic draft gage ameliorate the traditional pointer type instrument, which change the traditional pointer show into a visual display. Through these it reduce the problems of visual errors.
Pressure sensor changes the detected pressure signals into analog signals of mV level. Then these are magnified 0~5 Voltage signals by amplifier and sent these to the analog input of AD converters. AD converter transforms the analog signals to the corresponding digital signals. And then the MCU reads the digital signals and transforms the corresponding codes. This paper transforms the 8 digital signals that are read into corresponding 0~2000PA pressure through the MCU that display on the four Nixie tubes.
This electronic draft gage also design the alarm function, which is completed through the three keys on the keyboard. The third key open and set off the alarm, the second key is the lower limiting alarm button; the first key is the upper limiting button. The highest ceiling LED displays 0 and flash when the upper limiting button alarm and the higher ceiling LED display 0 and flash when the lower limiting button alarm.
