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Valve positioners are widely used in everyday life and are very popular among the public. The internal structure of this locator is clear and simple; it mainly consists of a SPAN span adjustment mechanism, an amplifier, a feedback cam, a constant-throttle orifice, nozzles, a zero-point adjustment device, baffles, etc. Its internal construction principle is basically similar to that of other locators. The valve positioner features a 4-20mA feedback control regulating element and a potentiometer. The 4-20mA feedback control regulating element consists of an INPUT terminal for connecting the 4-20mA control signal, wiring terminals, a SUPPLY terminal for connecting to a 24VDC DC power source, and 4 interfaces; a wire needs to be connected to each of these components. A potentiometer, also known as a knob resistor, can be used to detect the actual angular displacement of a positioner. Each component in the instrument has its own function, and these components complement each other with clear divisions of labor, thereby enabling the full advantage of the locator’s performance. Operation principle of the valve positioner: When the input current (DC4~20mA) increases, through the input processing circuit, calculation processing circuit, and output processing circuit on the substrate, the current flowing into coil 0 of the torque motor changes, causing armature 0 to swing around plate spring 0 as a pivot. With this action, the gap between the nozzle and the baffle opens, and the back pressure inside the nozzle decreases. As a result, the exhaust spool inside the pilot valve moves to the right, the pressure on the OUT1 side rises, and the diaphragm valve operates. The operation of the diaphragm valve is transmitted to the displacement output processing circuit on the substrate via the feedback shaft 0, angle sensor 0, and feedback lever; through computational processing, the output current is made to match the position of the input current. When using a valve positioner, in order to extend its service life, it is necessary to clean the positioner on a regular basis, which helps to prolong its lifespan. So how should the locator be cleaned? The following will introduce it to you. Cleaning of valve positioners: 1. If there is nesting or infestation in the valve positioner system, or if there are signs of insects or animals on the positioner, remove the pests and then clean the positioner unit ； 2. If obvious pet hair, odors, debris, or other contaminants are released into the room through the ventilation openings, it may be necessary to clean the locator ； 3. If obvious mold growth occurs inside the valve actuator, the actuator system should be cleaned ； 4. During home renovation, valve positioners are not sealed; especially when a large amount of dust or lead-based paint is removed, or when asbestos is cleared away, harmful debris and dust can accumulate inside the valve positioners, and it becomes necessary to clean these positioners at such times ； 5. If someone in your family suffers from unexplained allergies or related conditions, to determine whether it might be caused by the tracker, it is necessary to consider cleaning the tracker. Valve positioners can control fluid pipelines; their primary function is to enable or disable the flow of the medium in the pipeline, to change the direction of the medium’s flow, to regulate the pressure and flow rate of the medium, and to ensure the proper operation of the equipment in the pipeline. When using it in the future, it is necessary to clean it promptly so that the locator can perform its functions more effectively. The above has introduced to you the components of valve positioners as well as their operating principles during use, along with cleaning procedures. I hope this information will be useful to you when using them.