给定速度数值，模拟仪表显示。本程序以有轨电车的速度范围设计，程序模块清晰，看懂后较容易修改量程和量纲。(Given the speed value, the analog instrument is displayed. The program is designed for the speed range of tram, and the program module is clear. After reading, it is easier to modify the range and d