The industrial dissolved oxygen meter is a kind of online water quality monitor with a microprocessor. It is widely used in industrial water, domestic water, and sewage treatment, as well as aquaculture. Continuous monitoring and control of oxygen content in aqueous solution. The instrument is equipped with a liquid crystal display; Intelligent English and Chinese menu operation; With current or voltage output, measurement range can be arbitrarily set, high and low limit alarm and two groups of relay control switches, adjustable hysteresis range; and Automatic electrode calibration.