The NO2-201 is an online nitrite nitrogen digital sensor that may be used to find out how much nitrite ion is in water bodies. It has automatic temperature correction with Pt1000 and uses an industrial-grade detecting method. It is easy to install, has a high level of security, and can adapt to many situations. It can correctly measure the amount of nitrite nitrogen in bodies of water and give real-time, dependable data support for controlling water quality in many areas.
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Parameters
| Parameter Item | Technical Index |
|---|---|
| Measuring Range | 0~100.0mg/L, Resolution: 0.1mg/L |
| Measuring Accuracy | ±10% or ±2mg/L; Temperature Accuracy: ±0.5℃ |
| Operating Temperature | 0~40℃ |
| Storage Temperature | -5~40℃ |
| Operating Pressure | <0.1MPa |
| pH Range | 2.5~11pH |
| Temperature Compensation | Automatic Temperature Compensation (Pt1000) |
| Power Supply | 12~24VDC |
| Power Consumption | 0.2W@12V |
| Signal Output | RS-485 (Modbus/RTU) |
| Housing Material | 316L Stainless Steel |
| Protection Grade | IP68 |
| Mounting Method | 3/4NPT Pipe Thread, Immersion Mounting |
| Cable Length | Standard: 5m, Customizable |
| Calibration Method | Two-point Calibration |
Why choose this digital sensor?
- Correct measurement: Pt1000 automated temperature compensation and a pH range of 2.5 to 11
- Installation is easy since the 3/4NPT thread and adjustable cable length can be used in a variety of situations.
- Long-lasting design: housing made of 316L stainless steel and an IP68 rating for long-term immersion
- RS-485 (Modbus/RTU) works with all PLCs and DCSs, so you may link them easily.
- Low maintenance: uses little power, just needs to be calibrated every so often, and is easy to calibrate with two points.
Featured Applications
- Municipal sewage treatment: online monitoring of nitrite nitrogen in the inlet, process section, and outlet of the sewage treatment plant to ensure that the effluent quality meets the discharge standards;
- Aquaculture: Monitoring of nitrite nitrogen in freshwater/seawater aquaculture ponds and recirculating aquaculture systems to accurately control aquaculture water quality and prevent fish and shrimp diseases;
- Industrial wastewater detection: Real time monitoring of nitrite nitrogen concentration in wastewater from chemical, food processing, printing and dyeing industries to meet the requirements of wastewater treatment control;
- Environmental water quality monitoring: Long term monitoring of natural water bodies such as rivers, lakes, and groundwater to assist in water quality assessment and ecological protection;

Installation and wiring
Installation requirements
- When installing an immersion system with 3/4NPT pipe threads, the installation site should not have dead zones or places with a lot of bubbles, as these can affect measurement accuracy;
- The power supply should work with 12-24VDC, and the wiring should be weatherproof and sealed so that water doesn’t get in and cause problems.
- The cable is made to resist interference, so it should be kept away from significant sources of electromagnetic interference to keep the signal stable.
Maintenance
- Soak the sensing end of the sensor in tap water before use to activate it and ensure detection sensitivity;
- Rinse the sensor probe with distilled or deionized water in daily use, gently absorb surface moisture, and avoid wiping or scratching the sensing components;
- Regularly check whether the probe is attached with dirt and sediment, clean it in a timely manner, and prevent it from affecting the measurement accuracy;
- When the measurement error exceeds the standard, the two-point calibration method is used to recalibrate and verify the measurement data after calibration;
- Long term disuse requires cleaning the probe, drying and protecting it, and storing it in its original packaging at -5~40 ℃ in a dry environment.
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The NO2-201 online nitrite nitrogen sensor relies on precise measurement performance, industrial grade high protection design, and flexible installation adaptability to fully meet the online monitoring needs of nitrite nitrogen in multiple fields such as municipal, aquaculture, industrial, and environmental protection. It provides stable and reliable real-time data support for scientific water quality control and standard discharge, and helps various industries safeguard water environmental safety with professional quality.
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