Wide Range Probe for Gaseous & Dissolved Oxygen Measurements

OXYBase® WR-RS485 & WR-RS485M

The OXYBase® WR-RS485 & WR-RS485M combine an optical sensor type PSt3 and electro-optical module in one probe. The sensor has a maximum measurement range of 0 - 100 % O2, and a detection limit of 0.03 % O2. These probes are waterproof and can be submerged completely so they are ideally suited for e. g. environmental research applications, aquaculture, and measurements in sewage. They are connected directly to the control unit, and use RS485 as digital interface (OXYBase® WR-RS485 = PreSens proprietary, OXYBase® WR-RS485M = Modbus RTU). A serial communication protocol is offered for data exchange between the OXYBase® and a PC or other host unit. For initial operation the PreSens EOM-STS software can be used. The probes are available with various cable lengths, and their sensor is integrated in a removable sensor cap (OEC). These exchange caps are offered in different versions for certain demands (fast response time, safe for food applications, for measurements in aggressive environments, USP Class VI compatible). The sensor is not autoclavable.

  • Maximum measurement range of 0 - 100 % O2, detection limit 0.03 % O2
  • Ideal for e. g. environmental research, aquaculture
  • Waterproof
  • Communication via RS485 (PreSens proprietary or Modbus RTU)
  • Available with various cable lengths
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Oxygen Monitoring in Aquaculture

OXYBase® are the solution to control dissolved oxygen in aquaculture. The robust probes can be connected to control units so ideal water conditions can be assured, thus also helping to increase yield. OXYBase® are real low-maintenance probes, as a used sensor can simply be replaced by changing the OEC at the probe tip.

OXYBase® in Biological & Environmental Research

OXYBase® are long-term stable probes that can be implanted in soil or other samples for prolonged time periods. They are ideally suited for long-term monitoring of e. g. soil aeration processes, which are very critical for plant productivity, or dissolved oxygen measurements in water samples.


Specifications Gaseous & Dissolved O2 Dissolved O2
*at 20 °C, 960 - 980 hPa; humidified gas mixture
**after customized calibration
***determined changing from 20.9 % oxygen gas to nitrogen 5.0
****determined changing from air-saturated water to a freshly prepared 1 % sodium sulfite solution
Measurement range* Optimal: 0 - 50 % O2, 0 - 500 hPa
Max.**: 0 - 100 % O2, 0 - 1000 hPa
Optimal: 0 - 22.5 mg/L
Max.**: 0 - 45.0 mg/L
Limit of detection* 0.03 % O2, 0.3 hPa 0.020 mg/L
Resolution* 1 % O2 ± 0.02 % O2
20.9 % O2 ± 0.1 % O2
0.4 mg/L ± 0.009 mg/L
9 mg/L ± 0.04 mg/L
Response time (t90) < 10 sec.*** < 30 sec.****
Compatibility Aqueous solutions, ethanol, methanol, cleaning agents containing ClO2 at room temperature
No cross-sensitivity to pH 1 - 14, CO2, H2S, SO2, ionic species
Cross-sensitivity to Organic solvents such as pure acetone, toluene, chloroform or methylene chloride
Chlorine gas
Cleaning procedure 3 % H2O2, acidic agents (HCl, H2SO4) max. 4 - 5 %
Cleaning agents containing ClO2 at room temperature
Calibration Two-point calibration in oxygen-free (e. g. nitrogen 5.0, 1 % sodium sulfite solution) and air-saturated environment (20.9 % oxygen, air-saturated water)
Storage stability of sensor cap 5 years provided the sensor material is stored at room temperature in dry conditions and in the dark
Sampling rate 1 sec. up to 9 min. 59 sec.
Temperature sensor NTC
Temperature performance Accuracy < ± 1 °C
Power supply 5 - 30 VDC
Power consumption in active mode Max. 1 W
Power consumption in stand-by mode < 0.15 W
Temperature range operation Optimal: 0 °C to + 40 °C
Max.: - 10 °C to + 70 °C
Temperature range storage Optimal: room temperature (+ 20 °C ± 5 °C)
Max.: 0 °C to + 70 °C  
Pressure resistance* 3 bar
Dimensions Probe length: 106 mm, diameter 12 mm; various cable lengths available
Probe housing material Stainless steel SUS 316 L
Weight 100 g
Digital interface RS485 (PreSens proprietary or Modbus RTU)

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