Water level - capacitive (Trutrack)

Parameter to be measured:

water level

Method:

capacitive

Equipment:

TruTrack WT-HR xxxxx

Advantages:

• Cheap
• Easy to install
• Optional Logging of battery level, water and air temperature in 8 / 12 bit resolution
• Logging of 64 k of data
• Logger start by starting condition or start time

Disadvantages:

• Water level measurement is temperature sensitive. The internal temperature compensation does a unreliable job: (stronger) temperature changes MAY produce periods (up to 60 min) of very noisy data.
• Internal Logger calibration: The loggers can be calibrated for exact water level measurements. The loggers may loose this internal calibration for no apparent reason, producing raw data instead. If independent readings are available, the record may be saved by "post-calibration".
• No outside sign of logger operation: For checking the proper logger operation, you must connect a computer to the logger. A full/not activated/malfunctioning logger cannot be detected otherwise.
• Logger connects via serial port: For most modern laptops you will need a USB to Serial(RS232) adaptor, causing yet other problems (sic).
• Bugs in Logger-Software (OmniLog): The detection of the connected loggers is unstable. Detection may fail for no apparent reasons. Reinstalling the software may help. Another reason may be the slightly reduced voltage at laptop ports being insufficient for communication with the logger. Try a desktop computer. Bringing the loggers inside for a couple of hours/days may also help.
• If any of your records happen to coincide with midnight exactly, the data export to Excel will produce faulty date values for these records.
• Poor (=nonexistent) customer support: No problem-related reply of the manufacturer whatsoever has ever been reported. You will, however, get a quick answer if you make an inquiry about an item you'd like to order.

What to watch out for:

Make sure the inner rod is screwed tightly into the logger-unit. To check that you need to unscrew the metal casing from the logger-unit. Shaking during transport might also loosen this connection.

Links

Projects that used the above equipment:

- SESAM [1]

Other related web sites:

- Trutrack homepage [2]

References

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