Sensors and Transmitters

This post was last edited by liuei on 2010-11-12 at 10:23. Sensors are measuring elements, such as thermal resistors, thermocouples, strain gauge bridges, etc... Transmitters are amplifiers and converters that amplify the small signals detected and convert them into standard 4-20mA signals.

OP, in simple terms: a sensor is a detecting component that can detect physical variables of substances. For example, a pressure sensor can detect changes in pressure, and a temperature sensor can detect changes in temperature ； The transmitter is the processing component that converts the physical variables detected by the sensor into standard signals for display and control.

Thank you very much. I’ll rate it tomorrow; I’ve used up all my credits for today

Sensors are a general term for devices or apparatuses that can convert a specified quantity to be measured into an available output signal according to certain rules; they usually consist of sensitive elements or conversion elements. When the sensor’s output is a specified standard signal, it is called a transmitter. The concept of a transmitter is an instrument that converts non-standard electrical signals into standard electrical signals, while a sensor is a device that converts physical signals into electrical signals. In the past, physical signals were the ones referred to, but now other types of signals are also considered. Primary instruments refer to field measurement instruments or control instruments at the site, while secondary instruments are those that use the signals from primary instruments to carry out other functions such as control and display. Sensors and transmitters are originally concepts related to thermal instruments. Sensors convert non-electrical physical quantities such as temperature, pressure, liquid level, material properties, and gas characteristics into electrical signals, or they transmit physical quantities such as pressure and liquid level directly to transmitters. A transmitter amplifies the weak electrical signals collected by the sensor in order to transmit them or activate the control unit. Or a signal source that converts non-electrical quantities input by sensors into electrical signals, amplifying them for remote measurement and control. Analog signals can also be converted to digital signals as needed. Sensors and transmitters together constitute the monitoring signal source for automatic control. Different physical quantities require different sensors and corresponding transmitters. There is another type of transmitter that does not convert physical quantities into electrical signals; for example, a \"differential pressure transmitter\" used in boiler level gauges. This type of instrument sends the water at the bottom of the level sensor as well as the condensed water from the steam at the top, through instrument pipes, to both sides of the transmitter’s diaphragm. The differential pressure across these two sides drives a mechanical amplification mechanism that uses a pointer to indicate the water level. Of course, those that convert electrical analog signals into digital signals can also be called transmitters. The above is only a conceptual explanation of the difference between sensors and transmitters.

What is the difference between a transmitter and a sensor? (This is Baidu’s explanation) With the advancement of technology, the meanings of some technical terms have changed, often leading to misunderstandings. Sensors are such an example. A sensor, as it is referred to these days, consists of two parts, namely the sensitive element and the conversion element. Among them, the sensitive element refers to the part of the sensor that is capable of directly sensing or responding to the quantity being measured ； A conversion element refers to the part of a sensor that converts the quantity being measured, as perceived or responded to by the sensitive element, into an electrical signal suitable for transmission or measurement. Since the output signal of sensors is generally very weak, it needs to be modulated and amplified. With the development of integration technology, people have also placed this circuit along with circuits such as power supplies inside the sensor. In this way, the sensor can output usable signals that are easy to process and transmit. In the past, when technology was relatively underdeveloped, the so-called sensors referred to the sensitive elements mentioned above, while transmitters were the conversion elements mentioned above. Currently: There are many types of transmitters. Those used in industrial control instruments mainly include temperature transmitters, pressure transmitters, flow rate transmitters, current transmitters, voltage transmitters, and so on. In fact, the sensor has already been integrated with the transmission.

Sensors are the elements used for measurement, while transmitters convert the measured signals into 4-20MA electrical signals

Hehe, a sensor consists of two parts: one part is the sensing element； The other part is the transmitter. A transmitter is essentially a conversion circuit (that converts non-standard signals into standard signals).

Transmitters have one more function than sensors: the standardization of signals