Difference between revisions of "Water level - capacitive (Odyssey)"
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Line 23: | Line 23: | ||
*Each sensor needs to be calibrated. | *Each sensor needs to be calibrated. | ||
*the sensor is not compensated for temperature or electrical conductivity. | *the sensor is not compensated for temperature or electrical conductivity. | ||
− | *manufacture state the | + | *manufacture state the accuracy to be -+ 5mm, but in practice it tends to be -+1cm. |
+ | *temperature dependency: "tests in water temperatures of 0°C - 20°C have shown a variation (under estimation) of approximately 5mm" (manufacture statement). | ||
+ | *electrical conductivity dependency: "If the conductivity of the water is above 5000µS/cm the sensor is largely unaffected by fluctuations in conductivity whereby large changes result in very small variations in the recorded data" (manufacture statement). | ||
==What to watch out for:== | ==What to watch out for:== |
Revision as of 07:54, 16 July 2010
Parameter to be measured:
Water level
Method:
Capacitive
Equipment:
Odyssey
Advantages:
- Cheap
- Logging of 64k of data
- Logger start by starting start time
- The lack of an outer shroud makes it easy to transport the probes
- Available in different lengths
- Available with 2 sizes of brass weights
- The probe fits exactly on a 32 mm (ID) PVC pipe
- You can replace the batteries yourself
- Log-intervale can be event-controlled
Disadvantages:
- Each sensor needs to be calibrated.
- the sensor is not compensated for temperature or electrical conductivity.
- manufacture state the accuracy to be -+ 5mm, but in practice it tends to be -+1cm.
- temperature dependency: "tests in water temperatures of 0°C - 20°C have shown a variation (under estimation) of approximately 5mm" (manufacture statement).
- electrical conductivity dependency: "If the conductivity of the water is above 5000µS/cm the sensor is largely unaffected by fluctuations in conductivity whereby large changes result in very small variations in the recorded data" (manufacture statement).
What to watch out for:
- Don’t damage the wire.
Problems/Questions:
- After 2 years of use, two of my loggers would no longer connect to the computer. All others still worked fined.
- One of my loggers would only record data for a few seconds. Restarting the logger and letting it run until the storage was full seemed to take care of this.
- How do temperature/electrical conductivity influence the measurement.
Links
Projects that used the above equipment:
Other related web sites:
http://www.odysseydatarecording.com/odyssey_productsview.php?key=1