Optical Dissolved Oxygen Sensors
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
Legacy VisiFerm sensors will continue to be supported:
Optical Dissolved Oxygen Sensors for Hygienic Applications
Optical Dissolved Oxygen Sensors for Low-Level Applications
Optical Dissolved Oxygen Sensors for Submerged Applications
Do you know all the potential sources of DO measurement error?
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
Sensor Features
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Intelligent Sensors
An integrated microprocessor eliminates the need for an external transmitter. Sensor outputs options include: nA, 4 - 20 mA, and digital protocols.
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Sensor Caps
A variety of different cap designs are available depending on the installation
Learn More -
Bluetooth Sensor Management
VisiFerm mA / VisiTrace mA have integrated BT and the VisiFerm RS485 requires the optional Arc Wi adapter. All sensors are compatible with ArcAir software.
Specifications
| VisiFerm RS485 | VisiFerm mA | VisiTrace RS485 | VisiTrace mA | VisiWater | |
|---|---|---|---|---|---|
| Measuring Range (DO) | 4 ppb - 25 ppm | 4 ppb - 25 ppm | 0 - 2000 ppb | 0 - 2000 ppb | 4 ppb - 40 ppm |
| Measuring Principle | Optical DO | Optical DO | Optical 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, SIP | Autoclavable, 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 - 4 | VP8 | 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 1.4435 | Stainless steel 1.4435 | Stainless steel 1.4435 | Stainless steel 1.4435 |
| O-ring | EPDM | EPDM | EPDM | EPDM | EPDM |
* 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.
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
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
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App Note - Continuous Cyanobacteria - Limnospora (Spirulina) Monitoring in the MELiSSA Loop using Dencytee
Drift free long term biomass monitoring for better understanding of process dynamics -
App Note - Online monitoring of CHO cell culture
A suite of Hamilton sensors is used to continuously monitor batch fermentation of CHO cells for tighter process control. -
App Note - Arc DO, pH, ORP in wastewater treatment in coking plant
ArcelorMittal, the world's largest steel manufacturer, uses Arc sensors for the effluent treatmentin their coking plant in Ostrava, Czech Republic. -
App Note - DO in microbial fermentation
F. Hoffmann-La Roche, a Swiss multinational healthcare company, uses optical dissolved oxygen sensors in thier R&D department in Basel to monitor microbial fermentation.
Resources
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Catalog - Process Analytics
Download the Process Analytics sensor catalog to learn about the complete offering of Hamilton process sensors and accessories. -
Brochure - BioPharma
Innovative solutions for process analytics in biotechnological and pharmaceutical industries. -
Brochure - Arc Intelligent Sensors
Arc Intelligent sensors offer a new way to connect to your process control system.
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How do I communicate with an Arc sensor?
Arc sensors have a built-in micro-transmitter within the sensor. ArcAir software is a powerful tool to access data, configure and calibrate the sensor. This can be done with Bluetooth wireless communication or with a wired connection directly to a PC. -
Whats the difference between a VisiFerm sensor with ECS output and a sensor with Arc?
The ECS interface mimics a traditional polarographic DO sensor output signal (nA). The Arc output provides both 4 - 20mA and Modbus digital outputs. -
What is the expected lifetime and when should I replace my ODO cap?
ODO cap health is process specific, with a cap quality indicator in ArcAir representing the general health of the ODO cap. ODO cap quality replacement is advised at 35%, however, some customers may replace ODO caps as part of a preventative maintenance program before reaching 35%. Click to learn more.
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Optical Dissolved Oxygen Sensor Caps
There are several different options for optical dissolved oxygen (ODO) caps. This article provides recommendations for each product. -
Optical Dissolved Oxygen Cap Cleaning
Best practices for care and maintenance of optical dissolved oxygen (ODO) sensor caps. -
Optical Dissolved Oxygen Cap Quality
How do you know if the ODO cap on your sensor has degraded? This article gets into why these caps can degrade and how to assess them.
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