传感器是一种检测装置，能感受到被测量的信息，并能将感受到的信息，按一定规律变换成为电信号或其他所需形式的信息输出，以满足信息的传输、处理、存储、显示、记录和控制等要求。
传感器包括温度传感器：如热电阻、热电偶。压力传感器。流量传感器等
变送器是把传感器的输出信号转变为可被控制器识别的信号（或将传感器输入的非电量转换成电信号同时放大以便供远方测量和控制的信号源）的转换器。传感器和变送器一同构成自动控制的监测信号源。不同的物理量需要不同的传感器和相应的变送器。
变送器的种类很多，用在工控仪表上面的变送器主要有温度变送器、差压变送器、压力变送器、液位变送器、流量变送器、电流变送器、电压变送器、功率变送器等。
信号隔离器是将输入的信号，如电流信号、电压信号、热电阻信号、热电偶信号等，变送输出隔离的线性的电流或电压信号，并提高输入、输出、电源之间的电气隔离性能。
The difference and connection between sensors, transmitters and signal isolators
Sensor is a kind of detection device, which can sense the measured information and transform the sensed information into electrical signals or other required forms of information output according to certain rules to meet the requirements of information transmission, processing, storage, display, recording and control.
Sensors include temperature sensors such as thermal resistors and thermocouples. Pressure sensor. Flow sensors, etc.
A transmitter is a converter that converts the output signal of a sensor into a signal recognized by the controller (or a signal source that converts the non-electrical input of the sensor into an electrical signal and amplifies it for remote measurement and control). Sensors and transmitters together form an automatic monitoring signal source. Different physical quantities require different sensors and corresponding transmitters.
There are many kinds of transmitters. The main transmitters used in industrial control instruments are temperature transmitter, differential pressure transmitter, pressure transmitter, liquid level transmitter, flow transmitter, current transmitter, voltage transmitter, power transmitter and so on.
Signal isolator is to transmit the input signal, such as current signal, voltage signal, thermal resistance signal, thermocouple signal, etc., to output the isolated linear current or voltage signal, and improve the electrical isolation performance between input, output and power supply.
