DO9709 - Portable Instrument

Portable Instrument and data logger for D.O. measure

DO9709Mod.DO9709 is suitable to receive the input from polarographic Dissolved Oxygen sensors, with 2 or 3 electrodes, including the temperature sensor. The instrument can also be connected to 4 wires Pt100 temperature sensors and includes a barometric pressure sensor for D.O. measure compensation.

Portable instrument Mod.DO9709 also performs as a data logger by memorizing up to 30000 analysis data with configurable sampling period. Each data is related to time and date of analysis and can be sent to a pc or a printer through serial link RS 232C.

Thanks to great flexibility and large data logging capacity this instrument is suitable for D.O. monitoring in the most of the applications.

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Main features:

  • Input from D.O. and temperature sensors
  • Includes barometric pressure sensor
  • Data logger functionality, up to 30000 data
  • Configurable sampling intervals
  • Memorization of measured data, time and date
  • Serial link RS232C
  • Maximum, minimum and averaged value memorization
  • Fast calibration procedure
  • Advanced functionalities

Technical Specifications:

Measuring ranges (autoranging):

  • O2 in mg/l: 0.0090.0 mg/l, resolution: 0.01 mg/l (0.0019.99 mg/l); 0.1 mg/l (20.090.0 mg/l), Accuracy: 0.3 mg/l for 60110% RH, 1013 mbar, 2025°C
  • O2 in % saturation: 0.0600.0%, resolution: 0.1% (0.0199,9%) 1% (200.0600.0%),Accuracy: 0.3% for 0199.9 %; 2% for 200600 %
  • Temperature compensation: 0+50 °C
  • Barometric pressure measurement: 6001100 mbar, 1 mbar resolution. Accuracy: 2 mbar for 1825 °C; 2 mbar + 0.1 mbar/°C for -518 °C and 2550 °C
  • Sample salinity setting: setting limits 0.070,0 g/l, 0,1 g/l resolution
  • Temperature measure, input B: TP870 sensor (Pt100), range -50200 °C, 0,1 °C resolution
  • Display: LCD dual line, 3 ? digit, 12,5 mm; symbols
  • Keyboard: membrane, water tight
  • Operating temperature and RH limits: -550°C; 090% U.R., not condensing
  • Storage temperature limits: -2060°C
  • Power supply: alcaline battery, 9 V, average operation 100 h
  • O2 cell and temperature sensor connection: 2 circular connectors, 8 pin DIN 41524 female, A and B
  • Serial link connector: 9 pin connector sub-D male
  • Instrument housing: ABS
  • Dimensions: Instrument: 210x72x40 mm; Carrying case: 370x295x85 mm
  • Weight: Instrument: 350 g; kit: 1600 g.

Advanced Functionalities

Auto-power-off (can optionally be excluded); hold; relative data memorization and transmission through serial link; visualization of minimum, maximum and averaged values of O2 and temperature; Samplig interval setting (1 second to 12 hours); O2 measure compensation for temperature, barometric pressure and salinity.


The instrument is factory calibrated; at start up, when the sensor is connected, calibrate for zero and slope.
The instrument is supplied c/w zero calibration solution and slope calibrating system. Calibration procedure is very fast.
Mod.DO9709 meter also includes two point calibration procedure for temperature and for barometric pressure sensor.

Available Version

Mod.DO9709 portable dissolved oxygen meter and data logger, supplied c/w carrying case, zero solution, calibrator, temperature sensor, battery, serial link cable and Instruction Manual.

Accessories included in the supply:

Carrying case, Mod.DO9709 meter, Instruction Manual, 9V alcaline battery, temperature sensor TP870, serial communication cable CP RS 232C, calibrator, zero solution.

CP RS 232C serial link connecting cable includes 9 pin sub-D female connector and 25 pin sub-D female connector.

Dissolved oxygen sensor should be ordered separately (Mod.332/P). The sensor is supplied c/w the accessories kit including electrolyte bottle and 10 membranes.

Application Fields:

  • drinking water plants
  • wastewater treatment plants
  • food and beverage industry
  • fish breeding
  • hospital laboratories
  • biochemistry laboratories
  • miocrobiological laboratories

Operating principle:

Portable meter Mod.DO9709 measures D.O. concentration through a polaroghrafic cell, 2 or 3 electrodes, including the temperature sensor. The meter includes a barometric pressure sensor for measure compensation and can correct D.O. measured value for the salinity of the sample. Dissolved Oxygen concentration may be expressed in mg/l or in % of saturation.

The instrument can also be connected to 4 wires Pt100 or to Mod.TP870 temperature sensors for temperature readings in the limits –50°C a 200 °C; the meter can detect whether these sensors are connected or not and, if not, displays temperature and operates temperature compensation through the input given by temperature sensor integral to D.O. cell.

The data logger collects up to 30000 readings, with time and date. Sampling period can be set in the limits 1 second to 12 hours. Stored data can be printed or sent to a personal computer through the serial link (optocoupled) RS 232C.

Each acquisition block is ended with a report including maximum, minimum and averaged values. Instantaneous measurements can also be sent to the serial output for printing or memorizing on pc. Power supply is from alcaline battery, 9V, supplied; the instrument displays a symbol and generates a beep when the battery is low.

Mod.DO9709 meter is suplied c/w carrying case including battery, temperature sensor TP870, serial cable, zero solution, calibrator and Instruction Manual.