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.

OTT Orpheus Mini is equipped with a rugged, ceramic-capacitive measuring cell and a precise temperature sensor. A data logger, which can be configured individually, stores and manages the monitored measured values in a 4 MB non-volatile memory (corresponds to approx. 500,000 measured values). The power supply of the Orpheus Mini as well as the connection for downloading data and start-up are provided by the communication unit.

The infrared interface allows the data to be conveniently read out or transferred from the device with a laptop. A well structured, intuitive operating program with all the necessary functions for data output and export, configuration and calibration is supplied.

Technical Specifications

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


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)

Data logger

Memory 4 MB non-volatile
Number of measured values approx. 500,000
Reading interval 1 second …to 24 hours
Storage interval 1 second …to 24 hours
Logging type - selectable Linear, logarithmic - free progammable (logging table) for pumping tests, event triggered delta data logging


System length 1.5 m to 200 m, ±1%, ±5 cm (cable length incl. communication unit/pressure probe)
Material ABS, POM, 904 L (DIN 1.4539)
Weight Communication unit (incl. batteries): approx. 0.410 kg
Pressure probe:approx. 0.300 kg
Dimensions Communication unit: 400 mm L x 22 mm Ø
Pressure probe: 195 mm L x 22 mm Ø

Operating conditions

Temperature-compensated working range -5 °C to +45 °C (ice-free)
Storage temperature -40 °C to +85 °C
Operating temperature -20 °C to +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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