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PS-3224
Troubleshooting the Sensor
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SPARKvue Collecting Data
•
In SPARKvue, select the Start button to begin collecting data.
PASCO Capstone Set Up
Connecting the Sensor to a computing device (such as a computer) via Bluetooth
•
For PASCO Capstone, select
Hardware Setup
in the Tools palette. In
Hardware Setup
the sensors are listed
in order by proximity to the device. Select the address that matches the Device ID XXX-XXX number on the
sensor.
Select a display in the main window or from the
Display
palette. In the display, use the
<Select Measurement>
menu to pick a measurement to be shown.
Connecting the Sensor to a Computer with the Micro USB Cable
•
Connect the micro end of the included Micro USB Cable into the micro USB port on the end of the sensor.
Connect the other end of the Micro USB Cable to a USB port on the computer, or into a powered USB hub
connected to the computer.
•
In PASCO Capstone, select a display in the main window or from the
Displays
palette. In the display, use the
<Select Measurement>
menus to pick the measurement to be shown.
PASCO Capstone Collecting Data
•
In Capstone, select
Record
to begin recording data.
Troubleshooting the Sensor
•
If the sensor loses Bluetooth connection and will not reconnect, try cycling the ON button. Press and briefly
hold
the button until the status LEDs blink in sequence, and then release the button. Start the sensor in the
usual way.
•
If the sensor stops communicating with the computer software or tablet application, try restarting the software
or application. If the problem remains, press and
hold
the ON button on the sensor for 10 seconds and then
release. Start the sensor in the usual way.
•
Turn Bluetooth off and then back on. Retry.
Theory of Sensor Operation
Optical measurement methods that detect dissolved oxygen are based on the principle that dissolved oxygen
quenches both the lifetime and the intensity of the luminescence associated with certain chemical dyes. When
there is no dissolved oxygen present, the lifetime and intensity of the luminescence are at their maximum. The
luminescence of the dye and the amount of oxygen present have an approximately inverse proportionality.
The sensing element of the Optical Dissolved Oxygen Probe is inside the Sensor Cap. The sensing element has
two layers, The outer layer is a paint that acts as an oxygen permeable diffusion layer which allows oxygen
molecules to pass though while protecting the dye layer. The inner sensing layer is an immobilized polystyrene dye
layer that luminesces when excited with light of the correct wavelength. The probe measures dissolved oxygen by
emitting a blue light of the proper wavelength that causes the dye in the sensing layer to luminesce (glow) a red
color. Oxygen dissolved in the sample being tested continually passes through the diffusion layer to the dye layer,
affecting the luminescence lifetime and intensity of the dye. The sensor measures the lifetime of the luminescence
as it is affected by the oxygen with a photodiode and compares the reading to a reference.