HOBO® Water Level Logger vs the Competition
This paper highlights results from Onset's tests of the HOBO Water Level logger and comparable loggers from two competitors. Vendors specify water level data loggers in different ways, and we felt it would be valuable to compare accuracy under identical test conditions. All loggers tested have a 30-ft measurement range. Our testing concluded that while the data loggers have similar accuracy at a fixed temperature, the HOBO Water Level Logger had significantly better accuracy when there were changing temperatures. See the detailed test results below.
|HOBO® Water Level Logger||±0.015 ft||over the factory-calibrated range 0 to 40 °C (32 to 104 °F)|
|Competitor 1||±0.016 ft||with automatic temperature compensation, but no range specified|
|Competitor 2, Model A||±0.033 ft||over the factory-calibrated range 0 to 40 °C (32 to 104 °F)|
|Competitor 2, Model B||±0.016 ft||over the factory-calibrated range 0 to 40 °C (32 to 104 °F)|
Accuracy at a Constant Temperature
We tested the water level loggers in a constant temperature environment to collect data for accuracy deviation over a range of depths.
The HOBO® Water Level logger performed well in this test. The worst case error for the HOBO logger was 0.013 feet, while the worst case errors for the competitive loggers were 0.016, 0.027 and 0.029 feet respectively.
Temperature Compensation Accuracy
Accurate performance over temperature is particularly important for applications with varying water temperatures, such as streams, wetlands and tidal areas. We tested the water level loggers for accuracy across a range of temperatures.
The worst case error for the HOBO® Water Level logger in this test was 0.010 feet, while the worst case errors for the competitive loggers were 0.100, 0.023 and 0.077 feet respectively.
The HOBO was within its accuracy specification across the full range of temperatures tested, measuring 10 times more accurately than the Competitor 1 logger at 35 °C.
Barometric Pressure Logger Accuracy
We tested the HOBO® Water Level Logger's barometric pressure sensor against dedicated barometric pressure loggers from both competitors. The graph below shows the stability of the HOBO Water Level logger's sensor over the same range of barometric pressure as those dedicated loggers.
Measuring accurately over temperature is particularly important for barometric pressure loggers, since air temperatures can vary widely. When tested, the HOBO logger had accuracy similar to that of the two competitors' dedicated barometric pressure loggers when tested at a constant temperature.
For the temperature test, the HOBO and Competitor 2 had similar accuracy (0.0085 and 0.0095 feet of error respectively), while the logger from Competitor 1 had over twice as much error (0.0215 feet).
Other Advantages of the HOBO Water Level Logger:
The HOBO Water Level Logger has Guaranteed Accuracy
Onset guarantees the accuracy performance of HOBO U20 Water Level Loggers by providing a 3-point calibration certificate with every logger, showing measured accuracy versus a NIST-traceable standard.
The HOBO Water Level Logger uses a Robust Sensor
The HOBO U20 Water Level Logger uses a ceramic sensor, while Competitor 1's logger uses a stainless steel sensor. Stainless steel sensor diaphragms are the thickness of aluminum foil and are sensitive to any kind of shock. Even the shock from hitting water too hard can be enough to damage this type of diaphragm. Stainless steel sensors can also be damaged in freezing water, while ceramic sensors survive and continue to operate once the water thaws. Ceramic sensors are also suitable for use in salt water, while stainless steel sensors will corrode. Competitor 1's logger housing is protected by a zirconium coating; however, if scratched, this will actually increase the corrosion of the underlying stainless steel. For loggers that will be deployed in a corrosive environment, the best option is the titanium version of the HOBO Water Level Logger.
The HOBO Water Level Logger has a Factory-replaceable Battery
The competitive loggers' batteries are not replaceable. Although the competitive loggers claim a 10-year battery life, when they are used at fast sampling rates or at higher temperatures, their batteries can be depleted in months vs. years.
The HOBO Water Level Logger is part of the HOBO System
The HOBO Water Level Logger works seamlessly with other components in the HOBO System, including the HOBO waterproof shuttle for easy field offload and HOBOware software, well-known for its powerful graphing and analysis capabilities.
The HOBO Water Level Logger uses reliable optic communications
The completely sealed housing and optic communications in the HOBO Water Level Logger provide a reliable, easy way to offload data quickly to either the HOBO Waterproof Shuttle or a computer. Other loggers require additional mechanical connectors and spring-loaded pins for offloading, which can become corroded. The system uses USB communication to the computer for fast and convenient data offload.
Easy Import of Barometric Pressure Data
HOBO Loggers are Proven in Field Use
Used in more than one million deployments worldwide, HOBO data loggers have earned a reputation for reliable operation in harsh field conditions.
Data File Compatibility
HOBOware software is compatible with all HOBO Water Level Logger files and allows import of data from other manufacturers' water level loggers as well.
The HOBO Water Level Logger is the Best Value
The HOBO Water Level Logger provides accurate and reliable measurements at an affordable price. This logger not only offers 0.01 foot accuracy over a full temperature range, but its all-metal sensor mounting provides the dimensional stability necessary for repeatable measurements. Plus, the 13 foot model provides the highest accuracy among affordably priced water level loggers making it ideal for applications with less than 13 feet of change, such as wetlands. And, to ensure top-quality construction, the HOBO Water Level Logger is manufactured in-house following IPC 610 Class 2 specifications. You can be sure with the HOBO Water Level Logger that your investment will last for years to come.