499ado sensor is used to continuously detect the content of dissolved oxygen in the liquid, with the measurement range of 0-20ppm. It is mainly used in the aeration tank of municipal sewage and industrial sewage treatment plant, and also can be used to detect the content of dissolved oxygen in the aquaculture pool.            499ado is a diaphragm covered current sensor, which is composed of (gold) negative electrode, (silver) positive electrode and electrolyte. The negative electrode is covered with a diaphragm that allows oxygen to penetrate. During the working period of the sensor, the oxygen molecules in the measured liquid diffuse to the negative electrode through the diaphragm, and the polarization voltage applied on the negative electrode will reduce the oxygen molecules to the hydroxide ion, and then generate the current between the negative electrode and the positive electrode. The current is detected by the analyzer, which is proportional to the rate at which the oxygen molecules reach the negative electrode, and finally is positive to the concentration of dissolved oxygen in the measured liquid. Ratio.            Since the diffusion rate of oxygen molecules through the diaphragm depends on the temperature of the measured liquid, the response time of the sensor must correct the effect of temperature on the permeability of the diaphragm. PT100 temperature probe is built in the dissolved oxygen sensor, so the analyzer can automatically correct the temperature.            The calibration of 499ado sensor is very convenient. When the sensor is exposed to saturated air, press the relevant button on the analyzer. At this time, the analyzer measures the atmospheric pressure and calculates the equilibrium concentration of oxygen in the atmosphere under the current temperature and pressure. (delta analyzer, 1054abo and 1054bdo require the user to manually input atmospheric pressure value to the instrument.)            The maintenance of the sensor is also very convenient and fast. It is not necessary to use special tools or other fixed equipment to replace the diaphragm. Just drop a few drops of electrolyte in the diaphragm assembly, place it on the cathode, then place it on the cathode, and screw the retainer in place. When filling the electrolyte, turn the position of the sensor upside down and the position of the diaphragm upward, unscrew the liquid stopper located at the side of the sensor, then squeeze the plastic bottle containing the dielectric, and slowly drop the electrolyte from the filling port until the liquid level is lower than the lower part of the filling port (Note: 1. When charging the dielectric, there shall be no air bubble in the middle of the dielectric; 2. The liquid level of the dielectric shall not be higher than the filling port ), then reset and tighten the liquid stopper, and then return the sensor to normal position, i.e. the diaphragm is facing down, hold the upper part of it with the right hand finger, and shake it to the outside with force for several times, so that the charged dielectric liquid is completely connected with the dissolved oxygen diaphragm assembly, and remove the possible bubbles in the middle.            A flexible air bag is arranged in the sensor, which can automatically adjust the pressure change inside the chamber, maintain the pressure balance on both sides of the diaphragm, and prevent the diaphragm from deforming.            There are many ways to install the sensor. For the measurement application of air pool or water pool, the immersion installation mode is selected; for the measurement application of pipeline, the flow installation mode is selected.            499ado sensor can also be equipped with VP cable connector and a special cable, i.e. split structure. The VP male connector connected with the sensor can be quickly installed and removed with the cable equipped with the VP female interface. Once the wiring between the cable and the analyzer is completed, when the sensor is replaced later, there is no need to replace the cable or rewire it, and when the sensor is installed, the cable will not twist.