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OTT Orpheus Mini Water Level Logger

Pressure level transducer with datalogger for longterm groundwater monitoring

The OTT Orpheus Mini is an integrated pressure sensor and datalogger for level measurement in surface and groundwater applications. It features a robust ceramic measuring cell for long term accuracy and its built in datalogger manages and stores all measurements at user-programmable intervals.

  • Surface water, Groundwater
  • Vented pressure cell
  • Waterlevel/Pressure, Water temperature
  • Measures and stores water level and temperature data
  • 0 … 4, 10, 20, 40, and 100 m
  • ± 0.05% FS
  • Yes
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  • Accurate – Ceramic pressure cell, unlike membrane technology, will not deform over time providing long-term measurement stability
  • High Performance – Mechanical resistance to pressure overload and corrosive waters
  • Complete Solution – Pressure sensor with built-in data logger manages and stores pressure, depth to water, water level (stage), and/or temperature measurements at programmable intervals
  • Flexible Installation – Easily installs in wells or pipes of 1 in. diameter or larger with use of convenient adapter plates
  • Simple Maintenance – Infrared interface, batteries, and desiccant are accessible at the top of the well or pipe and no tools are required

For continuous or continuous real-time water level measurement of:

  • Streams, rivers, channels, or canals
  • Groundwater wells
  • Reservoirs, lakes, and wetlands

Ideal for monitoring:

  • Continuous water level networks
  • Short-term or long-term
  • Events
  • Pump tests
  • Landfill groundwater levels
Brief instructions Groundwater Datalogger OTT Orpheus Mini
Brochure - OTT Ground water measurement
Leaflet - Groundwater datalogger OTT Orpheus Mini
Operating instructions Groundwater Datalogger OTT Orpheus Mini
Orpheus Mini – Firmware - EN
OTT Orpheus Mini - CE Konformitätserklärung | Declaration of Conformity | Declaration de Conformité
OTT Water Logger Operating Program
Technical Note - Sensor Selection Guide Groundwater
USB interface drivers - OTT IrDA-Link USB - EN
White Paper - OTT ecoLog Guidance: Remote communication via mobile networks
Whitepaper - OTT ecoLog Guidance: Remote communication via mobile networks
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Waterlevel measurement
Measuring ranges 0 ... 4 m, 10 m, 20 m, 40 m, 100 m
Accuracy, pressure sensor ± 0.05 % FS
Resolution, pressure sensor 0.01 % FS
Temperature measurement
Measuring range temperature -25 °C ... +70 °C (ice-free)
Accuracy temperature ± 0.5 °C
Resolution temperature 0.1 °C
Electrical data
Power supply 3 x 1.5 V LR6-cells Alkaline- or Lithium-type
Lifetime (at 1 h reading interval)
with Lithium batteries min. 5 years
with Alkaline batteries min. 1.5 years (high quality battery types) 
Interface Infrared (IrDA)
Data Logger 
Memory 4 MB non-volatile
Number of measured values approx. 500,000
Reading interval 1 second …... 24 hours
Storage interval 1 second ...… 24 hours
Logging type - selectable linear, logarithmic - free progammable (logging table) for pumping tests , event triggered delta data logging
Installable in well pipes ≥ 1"
System length 1.5 ... 200 m ±1% ±5 cm (cable length incl. communication unit/pressure probe)
Material ABS, POM, 904 L (DIN 1.4539)
Communication unit (incl. batteries) approx. 0.410 kg
Pressure probe approx. 0.300 kg
Communication unit L x Ø 400 mm x 22 mm
Pressure probe L x Ø 195 mm x 22 mm
Operating Conditions
Temperature-compensated  working range -5 °C ... +45 °C (ice-free)
Storage temperature -40 °C ... +85 °C
Operating Temperature -20 °C ... +70 °C
Humidity 100 %  
Type of protection
Communication unit IP67 (immersion depth max. 2 m
duration of immersion max. 24 h)
Pressure probe IP68
EMV limits IEC61326/EN61326 are compliant with EN 61000-4-2, EN 61000-4-3, EN 61000-4-4, EN 61000-4-5, EN 61000-4-6, EN 550222 class B
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