Flow Sensors

CSM Correlation Sensor

Part No. CSM-V100

Measurements starting at flow levels of 3 cm

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

  • Infiltration measurement (extraneous water)
  • Influent control
  • Billing measurement places
  • Discharge constructions
  • Precipitation discharge measurements

The Mini sensor family provides the best possible sensors to detect lowest flow levels e.g. for infiltration measurement (extraneous water) or indirect discharge measurement.
The sensors use the proven ultrasonic cross correlation method patented by NIVUS. This method allows to detect and to indicate flow profiles starting at flow levels as low as a few centimeters.

Due to their shape the sensors are particularly suitable for small geometries and help to avoid backwater effects, the risk of build-up and clogging.

Typical applications for Mini sensors

  • Measurement campaigns in channel networks
  • Small WWTPs: intake and discharge
  • Industrial wastewater networks
  • Particularly suitable for channels featuring low flow levels



Technical Data

Flow Velocity Sensor, Type CSM

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

IP 68


II 2 G Ex ib IIB T4 Gb

Operating temperature

Wedge sensor without hydrostatic level measurement

  • −20 °C up to +70 °C for up to 15 min operating time
  • −20 °C up to +65 °C when used continuously
  • −40 °C up to +80 °C when used in Ex Zone 1


Wedge sensor without hydrostatic level measurement

  • −20 °C up to +50 °C
  • −40 °C up to +80 °C when used 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
  • 7/15 m, not extendable, for connection to electronic box / NivuFlow Mobile 750
  • 20 m (sensor with pressure cell only)
Outside cable diameter
  • Combi sensor with pressure measurement: 9 mm ±0.25 mm
  • Sensors without pressure measurement: 6 mm ±0.2 mm
Sensor connection
  • Cable end with plug for connection to Electronic Box EBM
  • Cable end with plug and pressure compensation element (sensors with pressure measurement cell only) for connection to Electronic Box EBM
Sensor types
  • v-sensor with T-compensation
  • v-sensor with T-compensation and h measurement (hydrostatic)

Wedge sensor for installation on the channel bottom

Installation Options
  • In pipes starting at 150 mm diameter (sensor with pressure cell) or 160 mm (sensor without pressure cell + air-ultrasonic sensor Type DSM)
  • In channels with a minimum width of 100 mm
Medium-contacting materials

Polyurethane, stainless steel 1.4571, PVDF, PA

Pressure compensationelement: POM-C, PMMA, PA, stainless steel 1.4571 (CSM-D only)

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 – 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 – 3.5 m)

Temperature measurement

Measurement range

−20 °C to +60 °C

Measurement uncertainty

±0.5 K

Specifications subject to change.

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 

Declaration of Conformity "Ex" ultrasonic sensors CSM / CSP / DSM / OCL-LM

IECEx Certificate of Conformity Sensor Family Mini and Transit Time Sensors

System Products
Related Products

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