Guide: Pressure sensor: When the steam boiler pressure acts on the diaphragm, the resistance value changes and produces a linear output signal proportional to the applied pressure. After the secondary conversion circuit, a two-wire system 4-20mA output is realized;

　　Pressure sensor: When the steam boiler pressure acts on the diaphragm, the resistance value changes and produces a linear output signal proportional to the applied pressure. After the secondary conversion circuit, a two-wire system 4~20mA output is realized;

　　Electric contact pressure gauge: It is composed of measuring system, indicating system, magnetic-assisted electrical contact device, housing, adjusting device and junction box (plug seat), etc.;

　　Pressure gauge: a device for measuring pressure, usually pointer pressure gauge and digital display pressure gauge;

　　Voltmeter: The function is to measure the voltage at both ends of the circuit;

　　Ammeter: The function is to measure the circuit;

　　Pressure controller: it is to detect the system pressure. When the pressure reaches the set value, the state of the auxiliary contact changes (normally open point is closed, normally closed point is disconnected). A control element is generally mechanical;

　　Temperature digital display meter: an instrument that can display temperature digitally;

　　Thermocouple: It is a kind of temperature sensing element, which converts the temperature signal into a thermoelectromotive force signal, which can measure the temperature of the measured medium;

　　Electrode type liquid level sensor: it is a digital quantity to measure the water level: high water level, medium water level, low water level, and extremely low water level;

　　Floating ball type liquid level sensor: It is an analog quantity to measure the water level;