The DO-200 dissolved oxygen meter is an online intelligent dissolved oxygen detection instrument developed by our company using imported technology. It incorporates imported components and a dissolved oxygen membrane head, combined with advanced manufacturing processes and surface-mount technology to ensure long-term stability and reliability. The electrode automatically detects zero point and slope exceedances. Optocoupler isolation protects the 4–20 mA signal output, ensuring no interference between input and output signals. It features EEPROM memory, eliminating the need for backup batteries and preventing data loss after power failure. With low temperature drift, high stability, and precision, its uniquely designed operation menu simplifies user interaction for unparalleled convenience. A large backlit LCD screen displays multiple parameters simultaneously (dissolved oxygen value, temperature, output current, etc.), making it intuitive and easy to read. The backlight automatically turns off after three minutes of non-use to save power and extend the instrument’s lifespan. Screen contrast is adjustable. High and low alarm points can be freely set, with alarm status displayed directly on the screen alongside ON/OFF signal output. Hysteresis can be arbitrarily configured to prevent frequent relay switching. Optional RS485 communication is available. The instrument is housed in a fully sealed, flame-retardant, waterproof, and gas-proof enclosure with an IP65 protection rating, making it suitable for use in harsh environments. It is widely applicable for continuous monitoring of dissolved oxygen in various solutions, including chemical fertilizers, metallurgy, environmental water treatment, pharmaceuticals, biochemistry, food, aquaculture, and tap water. Technical Parameters ■ Measurement Range: 0.00–20.00 mg/L ■ Temperature Compensation Range: Automatic 0–60°C ■ Resolution: 0.01 mg/L ■ Accuracy: ±1.5% FS ■ Current Isolation Output: 4–20 mA (Load < 500 Ω) ■ Alarm Relay: AC220V, 3A, isolated alarm signal output ■ Protection Rating: IP65 ■ Power Supply: AC230V±10%, 50/60 Hz ■ Operating Conditions: Ambient temperature 0–60°C, relative humidity ≤80%, no strong magnetic interference except Earth’s magnetic field ■ Data Retention After Power Loss: >10 years ■ Weight & Dimensions: 1 kg, 96×96×145 mm ■ Panel Cutout Dimensions: 92×92 mm ■ Secondary Meter Installation: Panel-mounted ■ Electrode Installation: Submersible/Pipeline ■ Electrode Type: Polarographic Electrode Standard Configuration One secondary meter, two fixing lock strips, one user manual, one electrode. Application Fields: Power plants, chemical industry, environmental water treatment, biological fermentation, aquaculture, pharmaceuticals, and other industries.