Explanation of the criteria for classification and numbering of components      C71.3.13
(JUN 00)
Explanation of the dates on the component's description



1.   Purpose and objectives

     To measure water level of dams, reservoirs and tidal level as well as water level of rivers with broader measuring range, 10m - 70m, by one sensor. Thus, this is a superb water level gauge from an economical point of view, too. Simple construction method and maintenance are another merit.

2.   Description

     The frequency of the Crystal Quartz Water Level Gauge reflects pressure stress fluctuations in such a way that any change in water level, that is water pressure in this case, converts itself into equivalent 
frequency shift of the crystal. This is converted to a digital signal for output and display. The mechanism guarantees accurate data free of any dispersion under any circumstances.

     This water level gauge can function fully automatically as a system for water level measurement and recording.

     The frequency seized as output of the sensor allows a direct measurement of change in water level as a digital quantity. This sensor enjoys a high resolution due to an excellent conversion rate and a large change in frequency as a function of pressure.

     Compact and not susceptible to any acceleration and gravity, it does not suffer any deterioration of its characteristics thereby ensuring far smaller power consumption.    

3.   Input

     Water pressure accompanying a change in water level.

4.   Output

     The external output of this unit is water level BCD signals to be delivered to telemeters and dam control systems. When combined with digital printers/recorders or with analogue recorders, it is versatile in any recording of water level desired.

5.   Operational requirements and restrictions

     Except for civil engineering works necessary for construction of the facilities to install this unit, the number of professional level personnel for its installation, operation and maintenance is of at least two.

     In case of recording the data measured at the recorder site, it is necessary to replace the paper tape periodically (about every 6 month: paper tape is required for 6 month use with max. one hour printing per day).

     When battery is used as the only power source, it is also necessary to replace it for a charged battery periodically.

     Ambient temperature is -10 to +40 C for the sensor, but no freezing is allowed. It is -10 to +40 C for the coder, with humidity 20 to 90 %, no condensing is allowed.

     There are 4 different ranges of water level measurable: 0 to 10 m, 0 to 20 m, 0 to 30 m, 0 to 70 m.

6.   Form of presentation

     A catalogue and specifications of the instrument and home page are available. (

7.   Operational experience

     Japanese users in more than 900 places may answer for the reliability of this water level gauge, which has been in use since 1984. Several units have been exported to Indonesia and China.

8.   Originator and technical support

     Takuwa Corporation.

9.   Availability

     From the HOMS National Reference Centre for Japan.

10.  Conditions on use

     The hardware is for sale.


(First entered: 1 FEB 93

Last updated: 21 APR 00)