Global Water Optical Dissolved Oxygen Transmitter w/25 ft. Cable
Specifications Sheet
Operation Manual
ItemDailyWeeklyMonthly
Unit w/25 ft. cable (#WQ-FDO-925 PN: DD0500) $41.25 $96.25 $275
The Global Water WQ-FDO Optical Dissolved Oxygen Transmitter is an instrument designed for measuring dissolved oxygen concentrations in liquids.  The WQ-FDO Optical Dissolved Oxygen Transmitters were developed to meet different requirements ranging from surface water monitoring programs to harsh waste water applications.  The optical dissolved oxygen transmitter 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 Transmitter has extremely low power requirements and a 4-20 mA output making it ideal for incorporation into remote environmental monitoring installations.

Methodology

The WQ-FDO Optical Dissolved Oxygen Transmitter'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.

Advantages

The WQ-FDO Optical Dissolved Oxygen Transmitter has many advantages over traditional DO sensors.  Unlike conventional galvanic and polargraphic dissolved oxygen sensors, WQ-FDO optical dissolved oxygen transmitters have no consumable cathodes or anodes that require replacement, minimizing servicing requirements.  Neither do the optical dissolved oxygen transmitters 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 transmitters can even be deployed in stagnate groundwater bores.  The WQ-FDO optical dissolved oxygen transmitters 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 transmitter 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 transmitters 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 transmitter's measurements.  There is no chemical interference from typical wastewater chemicals and the optical dissolved oxygen transmitters can withstand harsh wastewater applications.