YEX-S1-NHN Online Ammonium Nitrogen Sensor | RS485

YEX-S1-NHN is a high-precision online ammonium nitrogen sensor built on ion-selective electrode (ISE) technology with a patented long-life reference system. Ranges cover 0–10 / 0–100 / 0–1000 mg/L (selectable), with automatic temperature compensation and RS-485 Modbus RTU output (optional 4–20 mA) in a submersible IP68 body — reagent-free ammonium monitoring for sewage treatment, rivers and industrial effluent.

Where It Fits in the YexSensor Line

The YexSensor online water quality family is organized in three tiers: the S1 standard series (cost-effective probes in an IP68 engineering-plastic housing for high-volume monitoring points), the S1 PRO stainless-steel series (316L stainless-steel housings for seawater, high-chloride and oily duty), and the S2 flagship series (dual-interface RS485 + 4–20 mA connectivity for OEM and mixed analog/digital projects). If your duty is conventional municipal, industrial or agricultural water at scale, the S1 series is the economical choice; specify S1 PRO when corrosion resistance and higher accuracy are required.

Core Technical Highlights

• Three selectable ranges: from aquaculture-grade resolution (0–10 mg/L) to raw-inlet loads (0–1000 mg/L).

• Patented long-life reference: extends service intervals and stabilizes ISE drift between calibrations.

• Reagent-free ISE method: no chemical consumption, continuous data, low operating cost.

• Digital RS-485 Modbus RTU (optional 4–20 mA): integrate with PLC, SCADA and dataloggers.

• IP68 submersible body: aeration basins, ponds and channels; NPT 3/4 thread mounting.

Application Scenarios

WWTP aeration control:

1. track ammonium valleys to trim blower output while protecting the permit.

Discharge compliance:

2. continuous nitrogen records at the outfall with early-warning alarms.

Aquaculture and RAS:

3. toxic ammonia surveillance in ponds and recirculating systems.

River and lake stations:

4. nutrient-pollution event tracking on environmental platforms.

Technical Specifications

Contact our engineering team for the full datasheet and register map before ordering.

Frequently Asked Questions

How often does the ISE need calibration?

Typical practice is monthly slope verification with standard solutions, adjusted from your drift data. Compare against laboratory results at commissioning to anchor the site correlation.

Ammonium vs ammonia — which do I need?

Ammonium (NH4+) is what the ISE reports; un-ionized ammonia (NH3) — the toxic fraction for fish — depends on pH and temperature and can be derived from ammonium plus pH/temperature data. Confirm which quantity your permit or biology decision uses.

What information should I provide for a quotation?

Provide the water matrix, expected ammonium span, temperature range, installation method, cable distance, power supply and Modbus integration requirements, plus quantity and destination country.

What quality assurance is provided?

Every unit passes a standardized inspection process and a 72-hour high-temperature aging test before shipment, and is backed by a one-year warranty from the date of sale. Standard delivery includes the sensor, a 5 m four-core shielded cable, an instruction manual and a certificate of conformity.

Planning a ammonium nitrogen monitoring project? Send us your water matrix, range and control-system interface — our engineers will return a configuration proposal, Modbus register map and quotation within one business day.