Nitrate "OPUS" for fresh and salt water


Nitrate Probe Configurator

 Download OPUS Manual pdf

Fully Compatible with Kisters® Software 

Why are continuous nitrate sensors needed?

Nitrate in water can vary in three dimensions and in time due to many stressors

Sampling once per year, seasonally, or monthly does not provide adequate information about the variability of nitrate in the environment

OPUS is the new generation of spectral sensors for online measurement of nitrogen and carbon compounds. Through the analysis of a full spectrum, OPUS is able to deliver reliable readings for NO3-N, NO2-N, organic ingredients (CODeq, BODeq, DOCeq, TOCeq), and a number of other parameters.

OPUS features the new TriOS G2 interface, allowing fast and easy configuration of sensors by using a web browser. Integration into existing process control systems and external data loggers has never been easier.

With the optional battery pack, mobile applications are also feasible. WiFi connectivity allows laptops, tablets or smartphones to be easily used for control without any special application software or app installation.


  • Without sampling and preparation of test samples
  • Real-time sensor
  • Without reagents
  • Optical window with nano coating
  • Pre-installed application calibration 


  • Sewage treatment plants
  • Environmental monitoring
  • Drinking water monitoring
  • Industrial applications

Absorption spectrum with/without CODeq

Screen Shot 2020-04-16 at 3.29.40 PM

Technical Specifications

Measurement technology

  • light source: Xenon flash lamp
  • detector:
    • High-end miniature spectrometer
      256 Channels
      200 to 360 nm
      0.8 nm/pixel

Measurement principle: Attenuation, spectral analysis

Optical path: 0.3 mm, 1 mm, 2 mm, 5 mm, 10 mm, 50 mm

Parameter: See parameter list p. 3

Measuring range: See parameter list p. 3

 Measurement accuracy: See parameter list p. 3

 Turbidity compensation: Yes

Data logger: ~ 2 GB

 T100 response time: 2 min

Measurement interval: ≥ 1 min

Housing material: Stainless steel (1.4571/1.4404) or titanium (3.7035)

Dimensions (L x Ø): 470 mm x 48 mm (with 10 mm path); ~ 18.5“ x 1.9“ (with 10 mm path)


  • stainless steel: ~ 3 kg (with 10 mm path); ~ 6.6 lbs (with 10 mm path)
  • Titanium: ~ 2 kg (with 10 mm path); ~ 4.4 lbs (with 10 mm path) 


Interface: Ethernet (TCP/IP); RS-232 or RS-485 (Modbus RTU); 

Power consumption: ≤ 8W

Power supply: 12...24 VDC (± 10 %)

Maintenance effort: ≤ 0.5 h/month (typical)

Calibration/maintenance interval: 24 months

System compatibility: Modbus RTU

Warranty: 2 years

Max. pressure: 

  • with SubConn: ~ 435 psig
  • with fixed cable: ~ 43.5 psig
  • in FlowCell: ~ 14.5 psig at 0.5 to 1.0 gpm

Protection type: IP68; NEMA 6P

Sample temperature: +2...+40 °C

Ambient temperature: +2...+40 °C

 Storage temperature: -20...+80 °C

Inflow velocity: 0.1...10 m/s


 Measuring Range

Screen Shot 2020-04-16 at 4.01.33 PM

Single parameter under optimum laboratory conditions

  * Based on a standard calibration solution

** Based on KHP (100 mg/L COD standard solution correspond to 85 mg/L KHP)

*** Depending on composition of COD and BOD (checksum parameter)

1 mg/L NO -N correspond to 4.43 mg/L NO 33

1 mg/L NO -N correspond to 3.28 mg/L NO 22 

 OPUS G2 Interface

Screen Shot 2020-04-16 at 3.54.58 PM

The easiest and fastest way of sensor integration and configuration in any process control system or data logger via web browser:  

Let OPUS automatically monitor your processes and react to unexpected events or incidents with the optional "policing" feature of OPUS.

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Accessories for NICO and OPUS

G2plus interface:

G2plus Rev2

# G2plus: G2plus interface

G2 interfacebox:

11C100000: G2 interfacebox with WIFI

# 11C200000: G2 interfacebox without WIFI

11C000000: 2 G2 Interface Boxes without WiFi


Wiper W55:

02A100008: Wiper "W55 V2" is a mechanical wiper system for NICO and OPUS without wiper axis and wiper blades

Wiper blades: 


For W55 V2:

   # 02A100118  V2 Wiper blades set incl. wiper axis for 1mm path length

   # 02A100218  V2 Wiper blades set incl. wiper axis for 2mm path length

   # 02A100518 V2 Wiper blades set incl. wiper axis for 5mm path length

   # 02A100618 V2 Wiper blades set incl. wiper axis for 10mm path length

For W55 V1: 

     # 02A100108:Wiper blades set incl. wiper axis for 1mm path length

     # 02A100208:Wiper blades set incl. wiper axis for 2mm path length

     # 02A100508:Wiper blades set incl. wiper axis for 5mm path length

    # 02A100608:Wiper blades set incl. wiper axis for 10mm path length


 # 05A000005: Mounting assembly for submerged application Sensor float 



  #10A100005: Flowcell 0.3 to 10mmm

  #10A100007: Flowcell 50mm

  #10A100013: Flowcell 0.3 to 10mmm with panel mount

  #10A100015: Flowcell 50mm with panel mount

Valtub (Calibration shell):

# 10A300000: VALtub 10 mm Cal. Shell

# 10A300001: VALtub 50 mm Cal. Shell


 SID-12 Converter: 


11C100001: SDI-12 Coverter

Video: Lens socket change










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