4 20ma temperature and humidity sensor
4 20ma temperature and humidity sensor is a device that converts temperature and humidity signals into analog current signals (4-20mA), which is widely used in industrial, agricultural, medical, and environmental monitoring fields. It converts the signals collected by the temperature and humidity sensor into a standard 4-20mA current signal for transmission and control.
Principle of operation
The 4 20ma temperature and humidity sensor is usually composed of a temperature sensor, a humidity sensor, a signal conditioning circuit, an AD converter circuit, and an output circuit. The signals collected by the temperature and humidity sensor are processed by the signal conditioning circuit and then sent to the AD converter circuit for analog-to-digital conversion, and the converted digital signals are then converted to 4-20mA current signals by the output circuit.
Meaning of 4-20mA
4 20mA means that the minimum current is 4mA, the maximum current is 20mA, the upper limit of 20mA is taken because of explosion-proof requirements, 20mA current breakage caused by the spark energy is not enough to ignite the gas and other gases, gas sensors is very important because the spark energy is too large may ignite flammable and explosive gases, resulting in unimaginable consequences.
The reason why the lower limit is not taken as 0mA is in order to be able to detect the disconnection: it will not be lower than 4mA in normal operation, when the transmission line is disconnected due to a fault, the loop current is reduced to 0. 2mA is often taken as the disconnection alarm value. Another reason is that in the 4-20mA is used in the two-wire system, that is, two wires that is the signal line, but also the power line, and 4mA is to provide the sensor with the static operating current of the circuit.
Functional features
- Good linearity: the current signal output from the 4 20ma temperature and humidity sensor has a linear relationship with the temperature and humidity, which has a good linearity.
- High accuracy: the use of high-precision temperature and humidity sensors can provide accurate measurement results.
- Good stability: with good stability and reliability, it can work stably for a long time.
- easy to install and maintain: adopting a standardized interface and installation method, easy to install and maintain.
- with data storage and transmission function: you can store the measurement data inside the transmitter and transmit the data to the control system or data acquisition system through the communication interface.
Application Fields
- industrial automation field: used to measure and control the temperature and humidity in industrial production process, improve production efficiency and product quality.
- agricultural field: used to measure and control the temperature and humidity in a greenhouse, to promote the growth of plants. 3. medical field: used to measure and control the temperature and humidity in the medical field, to promote the growth of plants.
- medical field: used to measure and control the temperature and humidity in hospitals, laboratories, and other places, to ensure the normal operation of medical equipment and experiments.
- Environmental monitoring field: used to measure and monitor the temperature and humidity in the atmosphere, water, and other environments, to provide data support for environmental protection.
4-20ma temperature and humidity sensor is a very important environmental monitoring equipment, which can provide accurate temperature and humidity data for the fields of industry, agriculture, medical treatment, and environmental monitoring to ensure normal production and life. As people’s requirements for environmental comfort and product quality continue to improve, the application prospects of 4-20ma temperature and humidity transmitters will be more and more broad.
