The sensor is capable of a predetermined sum of the measured and converted into the available output signal of the device or apparatus according to certain rules, usually by the conversion element and the sensitive element. When the output of the sensor is a predetermined standard signal, it is called the transmitter.

    Transmitter is non-standard electrical signal is converted into a standard electrical signals instrument or device, the sensor is to convert the physical signal into an electrical signal devices, physical signals used to say, there are still other signals.

    Refer to the on-site measuring instrument or base control table, the so-called primary instrument, secondary instrument is the use of a table signal the completion of other functions: for example, control, display meter.

The sensor and transmitter was originally the concept of thermal instrumentation. The sensor is a non-electrical physical quantities such as temperature, humidity, pressure, materials, and characteristics of a gas, is converted into an electrical signal or sent directly to the physical quantities such as pressure, depth, etc. transmitter. Transmitter is collected by sensors to a weak electrical signal to be enlarged in order to transfer or start control elements. Or non-power sensor input is converted into an electrical signal to be amplified so that the signal source for the the distant measurement and control equipment needs. Needed also for converting analog to digital signals. Constitute automatic control monitoring with sensor and transmitter signal source. Different physical quantities require different sensors and the corresponding transmitter. There is also a transmitter is not a physical quantity is converted into an electric signal, such as a boiler water level of the differential pressure transmitter, it is the level sensor in the lower water and upper steam condensate through instrumentation tube Get to the transmitter is on both sides of the bellows, the bellows differential pressure on both sides to boost the mechanical amplification device to a meter pointer indicates the water level. Of course, there is the electrical analog signal into a digital signal can also be called a transmitter. These are just simple conceptual description of the difference between the sensor and transmitter.