一、设计安装转速表的必要性 DE～719C是美国新近生产的超声波测深仪,广泛用于航道及江河湖海的水下地形测量,具有精度高、耗电小、操作方便、稳定可靠等特点。近年来国内不少单位相续购进,使用效果较为满意。众所周知,记录式测深仪测深精度与电机转速的稳定性有着直接的关系,若转速不稳或转速不准,将直接影响测深精度,进而影 First, the need to design and install tachometer DE ~ 719C is the United States recently produced ultrasonic sounder, widely used in waterway and rivers and lakes underwater topographic measurement, with high precision, low power consumption, easy operation, stable and reliable Features. In recent years, many domestic units continued purchase, the use of more satisfactory. It is well-known that the sounding accuracy of the recording sounder has a direct relationship with the stability of the motor speed. If the speed is not stable or the speed is not accurate, the sounding accuracy will be directly affected,