Field-installation Type Dissolved Oxygen Meter(Two-Wire Transmission, Membrane Type)

HD-300 connects the DO (Dissolved Oxygen) sensor (DO-1100) and measures the DO in the sample water.The measurement method is membrane type polarography method. It is suitable for monitoring DO in wastewater treatment or aquarium for aquaculture.

Measurement range

Dissolved oxygen concentration: 0 - 20 mg/L
Saturation degree: 0 - 200 %
Temperature: 0 - 50 ℃

Division: Process Water
Manufacturing Company: HORIBA Advanced Techno Co., Ltd.


  • Responds to harsh conditions at the site process
    Operating temperature range(Transmitter):-20 - 60℃   
    Rated voltage: DC 24 V
    Robust aluminum die cast (Protection code:IP65)
  • CE Marking and FCC Compliance suitable for use at overseas sites



  • Self-diagnosis of membrane damage and infiltration into the probe
  • Convenient function to display liquid temperature at the same time(Transmission output available)
  • Designed to be environmentally friendly (Pb-free) in response to WEEE and RoHS


Easy maintenance

  • Easy to view big display
  • Easy operation
  • Calibration log memory
  • Screw terminals that do not fall off are used in the terminal block for wiring
  • Span calibration by air preceded by auto-zeroing (Electrical auto zeroing function)
  • On-site membrane replacement as well as whole sensor replacement
Product nameDissolved oxygen meter
Combined sensor5505, 5510 (A bipolar diaphragm type polarography sensor)
Combined probeDO-1100
Dissolved oxygen
0 mg/L to 20 mg/L (Display range: 0 mg/L to 22 mg/L)
Saturation degree0% to 200% (Display range: 0% to 200%)
Temperature0℃ to 50℃ (Display range: -10℃ to 110℃)
Dissolved oxygen
0.01 mg/L
Saturation degree1%
RepeatabilityWithin ±0.5% of the full scale (response for equivalent input)
LinearityWithin ±0.5% of the full scale (response for equivalent input)
TemperatureRepeatability±0.5℃ (response for equivalent input)
Linearity±0.5℃ (response for equivalent input)
Output type4 mA to 20 mA DC: input/output isolated type
Load resistanceMaximum: 600 Ω(when power supply voltage is 24 V DC) (*1)
LinearityWithin ±0.08 mA (output only)
RepeatabilityWithin ±0.02 mA (output only)
Output rangeDissolved oxygen concentration: Selection from preset ranges or free range input within measuring range.
Occasional out for errorHold or burnout to either 3.8 mA or 21 mA
Transmission holdIn the maintenance mode, transmission signal is held at the latest value or preset value.
In the calibration mode, transmission signal can be alive or held.
Contact inputNumber of input points1
Contact typeNo-voltage a-contact
ConditionsON resistance: 40 Ω maximum.
Open voltage: 1.2 V DC
Short-circuit current: 21 mA DC
Contact functionExternal input for transmission holding.
Applicable temperature
Platinum resistor: 1 kΩ (0℃)
(The temperature sensor is built into the probe DO-1000.)
Temperature compensation
0℃ to 50℃
Temperature calibration1 point calibration comparing to reference thermometer
CalibrationCalibration methodSpan calibration in the air or DO saturated aquaous solution
Number of calibration pointsAtmospheric calibration: 1 point
(Zero electric calibration is carried out automatically)
Saturation liquid calibration: 2 points (zero calibration is omitted)
Additional capabilitiesSalinity compensation (0.0% to 5.0%)
Automatic detection of calibration failure (Zero error, Sensitivity error)
Calibration history (Elapsed days from the last calibration which ever zero or span, zero shift, span sensitivity)
Self-checkCalibration errorZero calibration error, sensitivity error, outside of temperature calibration range
Electrode diagnostic errorSensor error (damage to diaphragm), disconnection of sensor (or damage to sealing), temperature sensor short-circuit, and electric discontinuity of temperature sensor
meter errorCPU error, CPU error, ADC error, memory error
Operating temperature range-20℃ to 60℃ (without freeze)
Operating humidity rangeRelative humidity: 5% to 90% (without condensation)
Storage temperature-25℃ to 65℃
Power supplyRated voltage24 V DC (operating voltage range: 21 V to 32 V DC)*1
Power consumption0.6 W max.
CE markingEMC  :EN61326-1
     Class A, Industrial electromagnetic environment
RoHS  :EN50581
     9. Industrial monitoring and control instruments
FCC rulesPart15 Class A
StructureInstallationOutdoor installation type
Installation methodAttached to 50A pole or wall
Protection codeIP65
Case materialAluminum alloy (coated with epoxy-denatured melamine resin)
Material of fittingsSUS304
Material of hoodSUS304 (Epoxy degenerated melamine resin painting)
Material of windowPolycarbonate
Display elementReflective monochrome LCD
External dimensions180 (W) × 155 (H) × 115 (D) mm (excluding mounting brackets)
MassMain body: Approx. 2.8 kg
Cover and mounting brackets: Approx. 1 kg

*1: The maximum load resistance that can be connected is decided depending on the power-supply voltage.

Relation between power supply voltage and load resistance


An arrester (spark over voltage: 400 V) is implemented for transmission output, contact input, and communication. However, use a most suitable surge absorption element on the connection lines in accordance with the ambient environment, the situation of equipment installed, and the externally connected equipment.

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