Significant Features: ① Automatic cleaning sensor allows setting the cleaning time and interval for the probe. ② One-key restoration (if non-professional operators perform incorrect operations, the device can be restored to factory settings via the restore key). ③ Simultaneous display of multiple parameters (temperature and mg/L displayed on the same screen). ④ Manual/automatic temperature compensation: automatically compensates when an external temperature-sensing element is connected; switches to manual mode when disconnected. ⑤ Automatic alarm function: isolated alarm signal output, customizable upper and lower alarm limits with hysteresis cancellation. ⑥ Startup self-check: each time the device is powered on, it automatically checks whether all parameters are within the normal range and can self-restore or correct if not. ⑦ Industrial watchdog: ensures the device does not freeze; designed with a built-in watchdog timer that automatically resets the device in case of abnormalities. ⑧ Online value correction function. Technical Parameters: 1. Measurement range: 0.00–19.99 mg/L 2. Resolution: 0.01 mg/L 3. Zero calibration range: 2.00 mg/L 4. Slope calibration range: 20%–180% 5. Temperature compensation: 0–45° (automatic or manual) 6. Relay control range: 0.00–19.99 7. Automatic cleaning time: 1s–99m59s 8. Cleaning interval: 1–720 min 9. Two signal outputs: 4–20 mA (residual chlorine), 4–20 mA (temperature) 10. Operating voltage: AC220V ±10%, 50/60 Hz 11. Dimensions: 185 × 155 × 115 mm 12. Installation method: Wall-mounted 13. Operating conditions: ① Ambient temperature: -5–55°C ② Relative humidity: ≤90% ③ No strong magnetic interference except the Earth's magnetic field.