The difference between pressure sensors, pressure relays and pressure switches

   The pressure sensor is composed of a pressure-sensitive element and a conversion circuit. It uses the pressure of the measured medium to generate a small change in current or voltage output on the pressure-sensitive element. The sensor often needs to be used in conjunction with an external amplifier circuit to complete the process from pressure detection to control and display. Since the pressure sensor is a primary element, the signal fed back by the pressure sensor needs to be processed, analyzed, stored, and controlled by the measurement and control system, making industrial automation equipment and engineering operation control more intelligent.

   The pressure relay is a hydraulic-electric switch signal conversion element that uses liquid pressure to open and close electrical contacts. When the system pressure reaches the set pressure of the relay, it sends out an electrical signal to control the action of the electrical element, realize the loading or unloading control of the pump, the sequential action of the actuator, the safety protection and interlocking of the system, etc. It consists of two parts: the pressure-displacement conversion component and the micro switch. According to the structural type of the pressure-displacement conversion component, there are four types: plunger type, spring type, diaphragm type and bellows type. Among them, the plunger type structure is divided into single plunger type and double plunger type. The single plunger type can be divided into three types: plunger, differential plunger and plunger-lever. According to the contact, there are single contact and double contact.

   A pressure switch is a functional switch that automatically connects or disconnects when the set pressure is reached.

   Pressure switches and pressure relays can only open or close switches under a given pressure, and are used for simple position control. They are both switch outputs! Pressure relays can provide more output nodes or node types than pressure switches. The output of pressure sensors can be analog signals or digital signals, which are easy to process at the later stage and can also be converted into standard transmitter signals for remote transmission.