The electricity that why uses 4~20mA will transmit imitate quantity?
[introduction] everybody may be familiar with RS232 very much, RS485, the commonly used bus line on the industry such as CAN, they are the means of transmission number signal. So, with what means we transmit imitate signal? General need measures the of all kinds physical quantity that be not report on industry, for example temperature, pressure, speed, angle, these need to be changed into imitate to measure telegraphic number ability to transmit hundreds of meters of control outside room or…