Onset Computer Corporation - 2 - LEDs > A light (LED) in the communications window of the logger confirms logger operation. The following table explains when the logger blinks during logger operation: Before you deploy the HOBO U20 Water Level Logger in the field, perform the following steps in the office: 1.Start HOBOware. 2.Connect the logger to the computer. See below. 3.Verify Status Click STATUS on toolbar and observe that the absolute pressure is near barometric pressure for the location and the temperature is near the actual temperature.4.Launch the logger. See the > The logger is logging...

Onset Computer Corporation - 4 - 5.Measure the water depth from the desired reference point (top of pipe, ground level, or sea level). Collecting Data To maximize accuracy, allow 20 minutes after deploying the logger before measuring water depth to allow the logger to reach temperature equilibrium with the water. For reading out the Water Level logger in the field, you can use either of the following: If the well is too small in diameter to measure the water depth after deployment, measure the water depth before deployment, then deploy logger immediately and record deployment time. Laptop computer...

Onset Computer Corporation - 5 - Barometric Data from Other Sources Third Party Weather Station or Barometric > To determine water level using barometric pressure data, use the Logger Barometric Compensation Assistant in HOBOware Pro, as described below. If you are using barometric pressure data from a HOBO weather station, you can use the data file as if it were U20 barometric data. For data from sources other than Onset products, see If you choose to use barometric pressure from a third party weather station or barometric logger, you need to convert the date, time, and pressure data to a text...

Onset Computer Corporation - 6 - Solvents of your HOBO Water Level Logger by comparing its ambient pressure readings to a second HOBO logger. Their readings should be within each others specified accuracy. Alternatively, you can check the pressure reading against an accurate local barometer. If you use a non-local source of barometric information, such as the NOAA website, adjust for altitude. Check a materials-compatibility chart before deploying the logger in locations where untested solvents are present: The logger is shipped with Viton O-rings installed. Viton has an excellent resistance...

Operation range 0 to 207 kPa (0 to 30 psia); approximately 0 to 9 m (0 to 30 ft) of water depth at sea level, or 0 to 12 m (0 to 40 ft) of water at 3,000 m (10,000 ft) of altitude Factory calibrated range 69 to 207 kPa (10 to 30 psia), 0 to 40аC (32 to 104аF) Burst pressure 310 kPa (45 psia) or 18 m (60 ft) depth Water level accuracy* Typical error - 0.05% FS, 0.5 cm (0.015 ft) water Maximum error - 0.1% FS, 1.0 cm (0.03 ft) water Raw pressure accuracy** 0.3% FS, 0.62 kPa (0.09 psi) maximum error Resolution < 0.02 kPa (0.003 psi), 0.21 cm (0.007 ft) water Pressure response time 90% < 1 second...

Operation range -20 to 50аC (-4 to 122аF) Accuracy 0.37C at 20аC (0.67F at 68аF), see Plot A Resolution 0.1C at 20аC (0.18F at 68аF) (10-bit), see Plot A Response time (90%) 3.5 minutes in water (typical) Stability (drift) 0.1C (0.18аF) per year > Accuracy Resolution ) Accuracy/Resolution (C 00.511.52 -2002040Temperature (аC) Plot A Real-time clock 1 minute per month 0Ѱ to 50C (32а to 122F) Battery 2/3 AA, 3.6 Volt Lithium, factory-replaceable Battery life (typical use) 5 years with 1 minute or greater logging interval Memory (non-volatile) 64K bytes memory (approx. 21,700 pressure and temperature...