



Onset
Dissolved Oxygen USB Data Logger
IMPORTANT INFORMATION
Requires HOBOware Pro software and either a U-DTW-1 Waterproof Shuttle or the Base-U-4 Optic USB Base Station for configuration and data offload.
Documentation
Data SheetUser Manual
Highlighted Features
- Affordable, high-performance dissolved oxygen (DO) monitoring with 0.2 mg/L accuracy
- Optical DO sensor technology for long-lasting calibration with less maintenance
- HOBOware Pro's Dissolved Oxygen Assistant software corrects for measurement drift from fouling; provides salinity-adjusted DO concentrations and percent saturation
- Optical USB interface for high-speed, reliable data offload
- User-replaceable DO sensor cap eliminates the need to send the logger back to the factory to replace the membrane
NOTE: For DO measurements in saltwater, an adjustment for salinity is required. For waters with small changes in salinity (<2 ppt), a salinity meter reading typically provides enough accuracy. For environments with greater salinity changes, we generally recommend the HOBO U24-002-C Conductivity logger. If you need DO in Percent Saturation, barometric pressure data is required, which can be logged with a HOBO U20-001-04 Water Level logger.
Specifications
Parameter | Value |
---|---|
Dissolved Oxygen | |
Sensor Type | Optical |
Measurement Range | 0 to 30 mg/L |
Calibrated Range | 0 to 20 mg/L; 0 to 35°C (32 to 95°F) |
Accuracy | ±0.2 mg/L up to 8 mg/L; ±0.5 mg/L from 8 to 20 mg/L |
Resolution | 0.02 mg/L |
Response Time | To 90% in less than 2 minutes |
DO Sensor Cap Life | 6 months, cap expires 7 months after initialization |
Temperature | |
Temperature Measurement/Operating Range | -5 to 40°C (23 to 104°F); non-Freezing |
Temperature Accuracy | 0.2°C (0.36°F) |
Temperature Resolution | 0.02°C (0.04°F) |
Response Time | To 90% in less than 30 minutes |
Logger | |
Memory | 21,700 sets of DO and temperature measurements (64 KB total memory) |
Logging Rate | 1 minute to 18 hours |
Time Accuracy | ±1 minute per month at 0 to 50°C (32 to 122°F) |
Battery | 3.6 V lithium battery; factory replaceable |
Battery Life | 3 years (at 5-minute logging) |
Download Type | Optical |
Depth Rating | 100 m (328 ft) |
Buoyancy | Saltwater: 13 g (0.46 oz) negative | Freshwater: 20 g (0.71 oz) negative |
Wetted Materials | Black Delrin®, PVC, EPDM o-rings, silicone bronze screws; rated for saltwater use |
Size | 39.6 mm diameter x 266.7 mm length (1.56 x 10.5 inches) |
Weight | 272.4 g (9.61 oz) |
Environmental Rating | IP68 |
Applications
In what environment does this data logger operate?
This data logger operates in an underwater environment.
What measurements does this data logger support?
The U26-001 data logger supports the following measurements: Dissolved Oxygen and Temperature