Explanation of the criteria for classification and numbering of components     C79.2.09
(DEC 00)
Explanation of the dates on the component's description



1.   Purpose and objectives

     To measure water velocities in rivers, streams, sewers and other open channels. Exceptionally high sensitivity down to 1mm/sec permits measurement in very shallow and sluggish flows, and is invaluable for hydraulic modelling.

2.   Description

     The instruments measure the velocity of water or other aqueous fluid flowing over a sensing probe. The measurement method uses the Faraday Principle of Electromagnetic Induction, where a conductor moving in a magnetic field has induced in it a voltage proportional to the speed of movement. In this case the water is the moving conductor, and the induced voltage is sensed by two electrodes on the probe.

     The probes have no moving parts, and the initial calibration remains valid for life. They are also unaffected by debris and suspended solids in the flow, making them ideal for sewer flow measurement and other difficult applications.

     Several versions of the instrument are available, all using the same probes and measuring principles. Probe cables may be up to 60m as standard. 

     SENSA- RC2 is a battery powered portable system for measurement of flow velocity over the range 0 to 4 metres/sec, with resolution down to 1mm/sec. LCD display of instantaneous or averaged readings, with RS232 output as standard.

     SENSA-RC3 is a battery-operated system for portable or semi-permanent applications. Fully bi-directional measurement from -8.00 to +8.00 m/sec, with 1mm/sec resolution. Selectable averaging and built-in data logging facilities with programmable sampling and time/date recording. LCD display 
for set-up and results. Standard RS232 output for real-time or stored data.

     SENSA-RMX is a multi-channel version of the Sensa-RC3 that can operate with up to 6 velocity probes simultaneously. All the measurement and data-logging functions are available for the selected probes.

     All instruments can display instantaneous velocity, or the velocity averaged over the range 2 to 60 seconds. Longer averaging periods may be supplied on request. Operating temperature is - 5 to + 50 C. The control boxes are rated to IP67, and are designed to float if dropped in the river.

     The optional Wading Rod Kit allows measurement at specified depths, in accordance with standard gauging procedures.

3.   Input

     Water flow along the axis of a submerged probe.

4.   Output

     Direct reading in metres/second of the velocity, displayed on the internal LCD display and also transmitted as an ASCII string from the RS232 output. Together with depth information provided by the Wading Rods, manual or computer calculations can be performed to calculate stream flow.

5.   Operational requirements and restrictions

     The instruments are designed for use by a single unskilled operator. Operation is extremely easy, and little training is required for basic measurements. Higher skill levels and training are suggested for gauging larger rivers.

     All the instruments are battery powered, using commonly available batteries. Rechargeable batteries are available as an option.

6.   Form of presentation

     Catalogues and specifications of the instruments are available.

7.   Operational experience

     Our instruments are used by Water Authorities, Universities and Environmental Agencies worldwide. Over 1000 have been supplied since 1990.

8.   Originator and technical support

     Aqua Data Services Ltd. England.

9.   Availability

     From Aqua Data Services Ltd
     Aquatec House,  Lyneham,  Wiltshire
     SN15 4PP
     Tel:    +44 1249 890724 
     Fax:    +44 1249 891329
     Web:  (also lists agents world-wide)

10.  Conditions of use

     Instruments are for sale direct from manufacturer or from agents.


(First entered: 1 DEC 00

Last updated: 1 DEC 00)