Nutrients Analyzer
Nitrate Meter

SMR21 series

Nitrate Analyzer

Nitrate Analyzer is connected directly via RS485 communication interface, providing simple, reliable, cost-saving process data with remote monitoring, calibration, configuration and diagnostics capabilities. Nitrate Meter housing in a robust IP68 proof enclosure, 1500 N tensile strength Kevlar reinforced cable, up to 1.2 km digital data transmission, the NO3-N analyzer and NO3-N Meter is ideally used in water/wastewater industry.
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  • All-in-One Compact Housing, Built-in Transmitter and Sensors
  • Robust IP68 Water Submersible Protection
  • Plug & Play, On- line Realtime Measurement
  • Ultra Low Power Consumption, Ideal for Outdoor Applications
  • 1500 N Tensile Strength Kevlar Reinforced Cable
  • Temperature and Chloride Compensation(SMR21-2)
  • Surge Protection for Power and RS485 Communication
  • RS485 Digital Communication, Minimize Cabling and Engineering Cost
  • Standard Modbus RTU Protocol, Direct Connected with PLC, HMI
  • Software Tool for Data Monitoring, Calibration , Configuration and Diagnosis
  • Very Stable Electrodes, without the Need of Frequent Calibration(SMR21-2)
  • Metal Membrane of Electrode to Prevent Scratch(SMR21-2)
  • Electrode is over 12 Months Long Period of Life(SMR21-2)
  • Sapphire Glass Windows to Prevent Scratch(SMR21-4~7)
  • Innovative Nano Coating to Remain Window Clean(SMR21-4~7)
  • Auto Cleaning Wiper, Less Maintenance
  • Chemical Oxygen Demand (COD) and Suspended Solids Compensation(SMR21-4~7)
  • Onboard Memory Allowing Users Easily Calibrate and Configure Sensor at Lab and Distribute to Various Fields Sites
  • AQCFG Software Tool for Data Monitoring, Calibration , Configuration and Diagnosis
Drinking water, water treatment, wastewater, fishery
  • Output Signal: RS485 (Modbus RTU protocol), 19,200 bps, 8 data bits, no parity, 1 stop bit; 4~20 mA
  • Data Resolution: 16 bits (0.001% FS)
  • Surge Protection: 4000 V DC
  • Power:12 V DC, 300 mA (SMR21-2); 12 V DC, 500 mA (SMR21-4~7)
  • Protection: polarity, overload, short circuit
  • Safety: CE, FCC
Measurement Method
SMR21-2: The ion selective electrode continuous measurement of nitrate is carried out with specific membrane that is selective of nitrate. That membrane creates charge seperation between the water surrounded electrode and internal filling solution. The charge is measured as a voltage that changes the concentration in the water adjacent the membrane. Compared with the traditional colorimetric method, there are many advantages such as fast response time, more accurate, easier and no reagents used.
SMR21-4~7: The Xenon flash lamp emits UV-Vis light passing through the sample to be analysed. The spectrometer resolve the wavelength into high resolution spectrum with advanced algorithms to provide the concentration and eliminates mutual interferences such as organic chemicals, turbidity and color.

SMR21-2 Nitrate Analyzer 
Type Ion selective electrode
Measurement range 0.1~100/1,000 mg/L, auto range
Accuracy ±5% in standard solution
Resolution 0.01 mg/L
Repeatability ±3% in standard solution
Operation pH pH 4~11
Operating pressure Max. 0.2 Kgf/cm²
Operating Temperature 0 ~ 40 °C
Process Flow Rate 0.1~4 m/s
Response time 2 min (90%)
Protection IP68
Sensor Pt1000
Measurement range 0~40 °C
Accuracy ±0.1 °C
Resolution 0.01 °C
Repeatability 0.1 °C
Measurement range 0.1~1,000 mg/L
Accuracy ±5% measured valie ±0.5 mg/L
Resolution 0.01 mg/L
Repeatability ±3% measured valie ±0.5 mg/L
Connection 1”-11 PT, 5-pin M16 plug
Housing POM
Dimension Φ 47 x 279 mm
Weight Nitrate analyzer: approx. 1.5 Kg
cable: 80 g/m
SMR21-4~7 Optical Nitrate Analyzer 
Type Optical
Measurement range SMR21-4: 0~5 mg/L (20 mm)(suspended solids< 200 mg/L)
SMR21-5: 0~20 mg/L (5 mm)(suspended solids< 1,000 mg/L)
SMR21-6: 0~100 mg/L (1 mm)(suspended solids< 5,000 mg/L)
SMR21-7: 0~300 mg/L (0.3 mm)(suspended solids< 5,000 mg/L)
Accuracy ±5% in standard solution
Resolution 0.01 mg/L
Repeatability ±3% in standard solution
Light Source Xenon flash lamp
Beam Angle 180 °
Light Path Length 1, 5, 20 mm
Process Flow Rate Max. 3 m/s
Operating pressure Max. 10 Kgf/cm²
Operating Temperature 0 ~ 50 °C
Response time 10 secs 
Protection IP68
Connection 5-pin M12 plug
Housing Titanium
Dimension Φ 75 x 416 mm
Weight analyzer: approx. 3.5 Kg
cable: 80 g/m