Hydrologic

LEVEL

measuring and recording water elevation in rivers, reservoirs, and ground water

LEVELMETER AND RECORDER

LPN 8/2 AND LPN 8/3


  • Level monitoring and recording.
  • Self-cleaning "bubble to bubble".
  • RS 232 / V 24 digital output.
  • Facility for measuring temperature, conductivity, dissolved oxygen, rain, etc...
  • Alarm thresholds.
  • Alert transmission.
  • Gray or BCD output via ISP 8.
  • No electronics underwater.
Functions
  Using a built-in compact air generator, LPN 8/2 and LPN 8/3 injects a small air flow through a pressure pick-up (BUBBLE TO BUBBLE).

This air pressure is applied to a SILICON MEMBRANE SENSOR which gives an electrical signal in proportion to the water height.

In order to improve result accuracy and credibility, LPN 8/2 or LPN 8/3 takes into account the following effects :

  • Temperature of pressure sensor.
  • Supply voltage.
  • Pressure in air reserve tank.

These signals are digitized and used by a MICROPROCESSOR which has the following functions :

  • Acquisition of digitized measurements.
  • Digital processing of measurements :
    • filtering,
    • compensation of temperature drifts,
    • compensation of interval drifts,
    • scaling.
  • Level monitoring with regard to the thresholds.
  • Compressor control to maintain a continuous air flow.
  • Monitoring normal internal operating conditions (temperature, voltage, pressure) with an alarm facility.
  • Storage control of compacted measurements in battery backed RAM (LPN 8/2).
  • Storage control measurements at fixed recording intervals (LPN 8/3).
  • Control of display unit and keybord for local operator dialogue.
  • Control of the asynchronous serial port communication V 24 / RS 232 C.
  • Control of the pneumatic circuit AUTOMATIC PURGING.
  • Facility for measuring temperature, conductivity, rain, dissolved oxygen, etc...).
  • Possible acquision and analysis of date using our software "OMNIDRO" IBM PC compatible or "TRADIDRO PLUS" IBM PC compatible.

    LPN 8/2 and LPN 8/3 is housed in a compact DIN 144 mm box and can be supplied in a wall cabinet.

Technical
specifications
 
Measurement range
Single built-in comp.
 0 - 5m or 0 - 10 m.
External compressor
 20 m - 60 m.
Resolution
Measurement scale < 10 m
 1 mm.
Measurement scale > 10 m
 1 cm.
Total error at 20°C ±0,1% FS on numerical value.
Temperature drift ±0,2% FS of sensor.
between -20°C et +60°
Measurement rate 5 to 120 sec.
Temperature range -20°C à +60°C
(-40°C à +60°C on request).
Relative humidity < 80% without condensation.
Operator dialogue
Display
 16 Alphanumeric characters.
Keyboard
 4 keys.
Serial link V 24 / RS 232 C.
Relay output 0.2 A / 220 VAC
(volt free contact).
Power supply 12 VDC (11.4 to 14.4 V).
12 VAC on request.
Consumption
Average
 10 mA
(without relay)
 Maximum 350 mA peak.
Box
Size
 144 x 144 x 165 mm.
Weight
 2,5 kg
Degree of protection
 IP 545.
Recording
Type
 Battery backed RAM.
Capacity
 Approx. 10 000 processed values.
Mode
 Compact (LPN 8/2)
Fixed recording interval (LPN 8/3).
1 to 60 minutes.
Data retrieval "OMNIDRO" or "TRADIDRO PLUS".
(PC computer)
Pressure purging
pick up		 Automatic.

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