A temperature transmitter is a device that converts physical measurement signals or ordinary electrical signals into standard electrical signals for output or signals that can be output via communication protocols. Temperature transmitters are instruments that convert temperature variables into standardized, transmittable output signals, primarily used for the measurement and control of temperature parameters in industrial processes. A current transmitter converts the AC current of the measured main circuit into a constant current loop standard signal, which is continuously transmitted to the receiving device.
A temperature transmitter is an instrument that converts temperature variables into a standardized, transmittable output signal. It is primarily used for the measurement and control of temperature parameters in industrial processes. It is widely used in on-site temperature measurement and process control in industries such as petroleum, chemical, synthetic fiber, textile, rubber, building materials, power, metallurgy, pharmaceuticals, and food; it is particularly suitable for computer-controlled measurement and control systems and can also be used in conjunction with other instruments.
Transmitters with sensors typically consist of two parts: a sensor and a signal converter. The sensor is mainly a thermocouple or resistance temperature detector (RTD); the signal converter mainly consists of a measurement unit, a signal processing and conversion unit (since industrial RTDs and thermocouple calibration tables are standardized, signal converters are also called transmitters when they are standalone products). Some transmitters also have a display unit, and some also have fieldbus functionality.
If a transmitter consists of two sensors used to measure the temperature difference, and the output signal has a given continuous functional relationship with the temperature difference, it is called a temperature transmitter.
There is a given continuous functional relationship (usually a linear function) between the transmitter output signal and the temperature variable. Early transmitters had a linear functional relationship between their output signal and the resistance (or voltage) value of the temperature sensor.
Standardized output signals are primarily 0mA~10mA and 4mA~20mA (or 1V~5V) DC signals. Other standardized output signals with special specifications are not excluded. Temperature transmitters can be classified into two-wire and four-wire systems according to their power supply wiring method, except for the RWB type temperature transmitter, which is a three-wire system.
Transmitters are available in electric unit combination instrument series and miniaturized modular type, as well as multi-functional intelligent type. The former do not have sensors, while the latter two types of transmitters can be easily combined with thermocouples or resistance temperature detectors (RTDs) to form transmitters with sensors.
