Flow Sensors

CS2/ CSP Correlation Wedge Sensor

Part No. CS2/CSP

Large measurement range for high flow levels

Ultrasonic sensors for flow measurement with very high accuracy in slight to heavily polluted media. For installation on channel wall or channel bottom

  • For high-accurate flow measurement by means of ultrasonic cross correlation method
  • Interference-free connection over long distances through digital signal transmission
  • Cables can be extended without any problems using standard cables
  • Absolutely stable zero point and drift-free
  • Measurement in heavily polluted and abrasive media
  • Easy installation without additional constructions and perfectly matched mounting accessories
  • Installation under process conditions possible
  • Suitable for all channel cross sections
  • The tailored selection of sensor constructions ensures the best possible solution for each application


CS2 flow velocity sensors are suitable for continuous measurement of slight to heavily polluted media in channels mainly featuring high levels.
The wedge-shaped sensors are designed for installation on either the channel wall or the channel bottom. Combined with transmitter types such as NivuFlow 750 and an external level measurement the result is a complete flow measurement system.

Typical applications for CS2 wedge sensors

  • Wastewater treatment plants: intake, discharge, activated sludge tank intakes, return sludge, recirculation, surplus sludge, digester discharge and flocculant dosage
  • Industrial wastewater networks
  • Large Collectors
  • Particularly suitable for large channels featuring levels starting at 500 mm






Technical Data

Wedge sensor for mounting on the channel floor or the channel wall

Measurement principle
  • Ultrasonic Cross Correlation with digital pattern detection (flow velocity)
  • Ultrasonic transit time (level measurement)
  • Piezo-resistive pressure measurement (level measurement)

IP 68

  • II 2 G Ex ib IIB T4 Gb (ATEX)
  • Ex ib IIB T4 Gb (IECEX)
Operating temperature
  • −20 °C to +50 °C
  • −20 °C to +40 °C if using the sensors in Ex Zone 1
Storage temperature

−30 °C to +70 °C

Operating pressure

max. 4 bar (combi sensor with pressure cell max. 1 bar)

Cable lengths

10/15/20/30/50/100 m pre-configured, can be extended upon request;

a pressure compensation element is required if cables longer than 30 m are used with sensors featuring an integrated pressure measurement cell. The compensation element can be used also to connect the extension

Cable types
  • Combi sensor with pressure measurement: LiYC11Y 2x1.5 + 1 x 2 x 0.34 + PA 1.5/2.5
  • Sensors without pressure measurement: LiYC11Y 2 x 1.5 + 1 x 2 x 0.34
Outside cable diameter
  • Combi sensor with pressure measurement: 9.75 mm ±0.25 mm
  • Sensors without pressure measurement: 8.4 mm ±0.25 mm
Sensor connection
  • Cable end pre-configured for connection to NivuFlow 750
  • Cable end with plug for connection to NivuFlow 750
  • Cable end with plug and pressure compensation element (sensors with pressure measurement cell only) for connection to NivuFlow Mobile 750
Sensor types
  • v-sensor with T-compensation
  • v-sensor with T-compensation and h measurement (water-ultrasound)
  • v-sensor with T-compensation and h measurement (hydrostatic)
  • v-sensor with T-compensation and 2 x h measurement (water-ultrasound + hydrostatic)
Medium-contacting materials

Polyurethane, stainless steel 1.4571, PPO GF30, PA6

Optional: sensor resistant to chemicals made of PEEK, mounting plate made of Hastelloy C-276; mounting plate made of titanium; cable with FEP coating

Flow velocity measurement

Measurement range

−100 cm/s to +600 cm/s

Quantity of scan layers recorded and computed

max. 32

Measurement uncertainty
  • for 0.05≤|V|≤0.5 m/s: E_v=0.5/|V| [%]
  • for |V|>0,5 m/s: E_v=1 %
Zero point drift

absolutely stable zero point

Beam angle

±5 degrees

Level measurement water-ultrasonic sensor

Measurement range

0.08 to 500 cm

Zero point drift

Absolutely stable zero point

Measurement uncertainty

+/− 2.0 mm or 0.2% of measured range (whichever is greater)

Level measurement – Pressure

Measurement range

0 to 500 cm

Zero point drift

max. 0.75 % of final value (0 - 50 °C)

Measurement uncertainty

standing medium: +/− 0.5 of final value (within a range of 0.05 – 5 m)

Temperature measurement

Measurement range

−20 °C to +50 °C

Measurement uncertainty

±0.5 K

Specifications subject to change.


Technical Instructions | Correlation Sensors (Rev. 09)

Technical instructions for correlation sensors and external electronic box

Installation Instruction | Correlation and Doppler Sensors (Rev. 07)

Installation instruction for save installation 

EC type examination certificate sensor type POA, OCL and CS2

EC type examination certificate sensor type POA incl. supplement

IECEx Certificate of Conformity "Sensors type POA, OCL and CS2"

Declaration of Conformity Ultrasonic Active Sensors POA / OCL / CS2

Ultraschall-Aktivsensoren POA / OCL / CS2

EU Declaration of Conformity | “Ex” Ultrasonic active sensors POA / OCL / CS2

System Products
Related Products

Haven't found the appropriate product?

You haven’t found the right product? Then use our application configurator – it will get you to the right product step by step.

Also for your individual measurement spot we support you gladly. Please fill in our questionnaire.

Product Consultation

You want to have best information about our products? Our experts will gladly develop together with you the best system solution for your application.


You have questions about your NIVUS products in use? Our service hotline will readily support you.

We are glad to have you here! For any question regarding water or digitisation we are happy to answer you call or your email message.
Im Täle 2
75031 Eppingen