The WQ-FDO Optical Dissolved Oxygen Sensor is designed for measuring dissolved oxygen concentrations in liquids. The WQ-FDO Optical Dissolved Oxygen Sensors were developed to meet different requirements ranging from surface water monitoring programs to harsh waste water applications. NOTE: Does not include armoring.
The optical dissolved oxygen sensor has been specifically designed to meet the demanding requirements of the environmental monitoring and scientific research sectors, providing long term, accurate and reliable dissolved oxygen measurement. The WQ-FDO Optical Dissolved Oxygen Sensor has extremely low power requirements and a 4-20 mA output making it ideal for incorporation into remote environmental monitoring installations.
- Specification Sheets
• Extremely fast and precise optical DO sensor – outstanding for field and lab applications
• Proven green light technology for long operation life of sensor
• Beveled membrane minimizes interference that can be caused by air bubbles
• Universal protective armoring available
• Low power consumption and maintenance
• Simple to integrate and operate
• One year sensor life
Methodology – Optical Dissolved Oxygen Sensor
The WQ-FDO Optical Dissolved Oxygen Sensor’s optical measuring technology is based on an attenuated fluorescent signal measured in a defined time frame. A fluorescent dye is stimulated in the optical dissolved oxygen sensor’s membrane by a short wave length light source. By falling back into the passive state, long wave light is emitted, which is recorded as a measurement signal. If oxygen contacts the dye by diffusing through the membrane the period of back scattering light is shortened according to the oxygen concentration of the sample. The optical dissolved oxygen measurement is more or less a highly precision time measurement. In order to process this time measurement as precisely as possible, the optical dissolved oxygen sensor optics are calibrated to the speed of light.
Optical Dissolved Oxygen Sensor Product Applications
• Long term monitoring of dissolved oxygen in streams, rivers and lakes
• Scientific research projects, both long and short term projects
• Water quality monitoring around industrial outfall
• Homeland security
• Thermocline profiling
• Fish farm and aquaculture water quality monitoring
• Wastewater industry
• Food and wine industry
Optical Dissolved Oxygen Sensor Advantages
The WQ-FDO Optical Dissolved Oxygen Sensor has many advantages over traditional DO sensors. Unlike conventional galvanic and polargraphic dissolved oxygen sensors, WQ-FDO optical dissolved oxygen sensors have no consumable cathodes or anodes that require replacement, minimizing servicing requirements. Neither do the optical dissolved oxygen sensors consume oxygen. Consequently the measurement of dissolved oxygen by the optical dissolved oxygen sensor is unaffected by water flow. The WQ-FDO optical dissolved oxygen sensors can even be deployed in stagnate groundwater bores. The WQ-FDO optical dissolved oxygen sensors have extremely stable electronics – a calibration interval of 1 year is typical.
The measuring and reference path optical components are identically designed inside this optical dissolved oxygen sensor. Natural aging processes of the optical dissolved oxygen sensor’s optical components can therefore be compensated by the reference path and accordingly compensated in the measuring path. As a result, the optical dissolved oxygen sensor provides accurate dissolved oxygen measurements over long periods of time without the need for re-calibration. Additionally by stimulating the fluorescent reaction in the membrane with low energetic green-light, the fluorescent dye in the sensor membrane won’t be bleached out.
The WQ-FDO optical dissolved oxygen sensors can be used to monitor dissolved oxygen in almost any liquid, including wines, beer, and milk. The optical dissolved oxygen sensors are not affected by color of the liquid. With the beveled membrane design bubbles or aeration do not affect the optical dissolved oxygen sensor’s measurements. There is no chemical interference from typical wastewater chemicals and the optical dissolved oxygen sensors can withstand harsh wastewater applications.
Global Water’s PC320 Optical Dissolved Oxygen Controller can use the optical dissolved oxygen sensor’s 4-20mA output to control pumps or alarms. In addition Global Water offers the GL500 optical dissolved oxygen data logger which adds recording capabilities and the ability to report DO concentration and saturation measurements from the 4-20mA optical dissolved oxygen sensor. The GL500 optical dissolved data logger connects to the optical dissolved oxygen sensor’s 4-20mA output, along with optional conductivity and barometric pressure sensors, to record highly accurate dissolved oxygen data.
|WQ-FDO DO Sensor|
|Dissolved Oxygen||Partial pressure: 0-400 mbar
Accuracy: ± 0.5 % of value
Repeatability: 0.01 ppm
Response time: 90% in less than 60 seconds
Sensor Drift: Less than 1% per year
Temperature: Compensated 32 to 122°F (0 to 50°C)
|Temperature||Accuracy: ±0.2°F (±0.1°C)
Resolution: 0.02°F (0.01°C)
Range: 32 to 122°F (0 to 50°C)
|Maximum Pressure||35 PSI (25 m/82 ft water depth)|
|Ouput||Dual 4-20 mA (Partial Pressure and Temperature)|
|Operating Voltage||10-30 VDC|
|Current Draw||24 mA plus both sensor outputs|
|Warm Up Time||6 seconds minimum, 8 recommended|
|Operating Temperature||32 to +122°F (0 to +50°C)|
|Size of Sensor||8 inch L x 0.86 inch Diameter (202 mm L x 22 cm Dia.)|
|Sensor Construction||Acetyl, stainless steel, cast epoxy|
|Weight||8 oz (227 g) plus cable|