VisiFerm mA RS485

Simplify your dissolved oxygen measurement

Optical sensors measure using an oxygen-sensitive fluorescent dye. The dye requires no equilibration time so it is instantly ready for use. A quality indicator displays the health of the sensor cap, and maintenance is as simple as removing and reinstalling the cap.

Introducing VisiFerm

The next generation VisiFerm drastically reduces calibration frequency and has a higher robustness.

See VisiFerm RS485 sensors See VisiFerm Ma Sensors

VisiFerm sensors for Dissolved Oxygen Measurement

Optical Dissolved Oxygen Sensors for Hygienic Applications

VisiFerm mA and VisiFerm RS485 sensors are designed to meet the demanding needs of hygienic applications in the biotech, pharmaceutical, and food and beverage industry. The VisiFerm mA is ideal for production environments with ATEX approval

Optical Dissolved Oxygen Sensors for Low-Level Applications

The VisiTrace optical oxygen sensor is specifically designed for low level dissolved oxygen down to ppb levels.

Optical Dissolved Oxygen Sensors for Submerged Applications

The VisiWater has a fixed cable making it ideal for submersible dissolved oxygen applications in the environmental water industry.

Do you know all the potential sources of DO measurement error?

dissolved oxygen whitepaper

Much has been written about different strategies for proper DO control. However, little information has been publicly available regarding optimization of the actual measurement accuracy and reducing common sources of process-related error.

Get Hamilton's whitepaper on potential sources of optical dissolved oxygen measurement error and ways to mitigate the impact.

VisiFamily Sensor Features


VisiFerm RS485VisiFerm mAVisiTrace RS485VisiTrace mAVisiWater
Measuring Range (DO) 4 ppb - 25 ppm 4 ppb - 25 ppm0 - 2000 ppb 0 - 2000 ppb 4 ppb - 40 ppm
Measuring Principle Optical DO Optical DOOptical DO Optical DO Optical DO
Process temperature -20 – 140 °C (no reading above 85 °C) -20 – 140 °C (no reading above 85 °C)-20 – 140 °C (no reading above 85 °C) -20 – 140 °C (no reading above 85 °C) 0 – 60 °C (no reading above 60 °C)
Pressure range -1 – 12 bar -1 – 12 bar-1 – 12 bar -1 – 12 bar -1 – 12 bar
Hygienic aspects Autoclavable, CIP, SIP Autoclavable, CIP, SIPAutoclavable, CIP, SIP Autoclavable, CIP, SIP None
Sensor Output ECS, 4-20 mA*, Modbus, Profibus*,
Foundation Fieldbus*
2 wire 4-20 mA (HART)4-20 mA*, Modbus, Profibus*,
Foundation Fieldbus*
2 wire 4-20 mA (HART) 4-20 mA, Modbus, Profibus*,
Foundation Fieldbus*
Sensor Connector VP8 M12 - 4VP8 M12 - 4 Fixed Cable
Surface Quality Ra < 0.4 μm (N5) Ra < 0.4 μm (N5)Ra < 0.4 μm (N5) Ra < 0.4 μm (N5) Ra < 0.4 μm (N5)
Material Stainless steel 1.4435 Stainless steel 1.4435Stainless steel 1.4435 Stainless steel 1.4435 Stainless steel 1.4435

* are achieved through a converter/adapter.

Benefits of going with Optical Dissolved Oxygen

Optical dissolved oxygen sensors offer a significant improvement over traditional amperometric sensors commonly used in the demanding applications found in pharmaceutical, biotechnology, and beverage applications. Process related drift due to carbon dioxide and other acid gases is fully eliminated with optical technology. Maintenance and calibration intervals can also be extended as optical sensors do not require electrolyte or internal cathode/anode replacement. Finally, optical sensors have no polarization time thus can accurately measure oxygen immediately upon power up.

  • Insensitive to CO2 fouling
  • Eliminates polarization
  • Simplifies maintenance with a single replacement part
  • No electrolyte to contaminate the process
  • Quicker response time
  • Measurement is independent of flow
  • Stable against pressure spikes
  • Can be installed inverted
  • Insensitive to poisoners like H2S and Ammonia

How does optical dissolved oxygen work?

The sensing element for an optical DO sensor is an oxygen sensitive luminophore. A blue light from the sensor excites the luminophore. When the excited molecule returns to its ground state it gives off red light. In the presence of oxygen some of the energy is transferred to the oxygen molecule. The oxygen measurement is made by comparing the excitation light (blue) to the emitted light (red).

Optical sensors are insensitive to CO2 fouling?

Over long fermentation runs, sensors are exposed to CO2 gas used for pH control or resulting from cellular respiration. The gas travels through the membrane of a polarographic sensor and changes the pH of the electrolyte. This change results in a lower nA reading.

Arc air software

The power of Arc connectivity

All optical sensors are compatible with ArcAir software. Connect wired or wireless to PC's, tablets, and mobile devices.

  • Simplify troubleshooting
  • Automatic documentation
  • Enhanced user security


Download our O2 Measurement Guide

O2 measurement guide

Get a better understanding of dissolved oxygen (DO) measurement in Hamilton's comprehensive O2 Measurement Guide. This 72-page booklet is intended for anyone with an interest in DO sensor technology or anyone who needs to implement DO sensors in controlled environments such as laboratories and industrial plants. The guide covers the following essential topics:

  • The basics of oxygen and its chemical and physical properties.
  • The physics of dissolved oxygen.
  • Types of DO sensors and how they work.
  • Applications, calibration, and maintenance of DO sensors.


Specific Applications


Hamilton's knowledge base provides a range of explanatory articles, frequently asked questions, and document downloads.
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