Water Data Loggers
Overview
HOBO MX800 Series multiparameter wireless data loggers work with interchangeable sensors to provide a highly configurable solution for monitoring water conductivity/salinity, temperature, depth, and dissolved oxygen. Available in both an easy-to-deploy, fully submersible model (MX801) and a direct read model (MX802) for convenient data offload that doesn’t require having to remove sensors from the water.
Top reasons customers like award-winning MX800 loggers:
- A less expensive, non-bulky alternative to sondes that can be difficult to calibrate and maintain
- Affordable price allows customers to purchase more loggers to swap in and out—saving time and optimizing data quality
- User-replaceable batteries
- 2-year vs. 6-month cap life saves resources needed to replace cap to prevent data loss
- Bluetooth prevents communication issues and the necessity of taking computer into the field
Features
- Compatible with interchangeable Conductivity, CTD (conductivity/temperature/depth), and DO sensors (sold separately) – swap out sensors for different applications
- Bluetooth, for easy logger configuration and data offload
- Easy to deploy, fully submersible (MX801)
- Direct read for convenient data offload (MX802)
- Logger diameter is less than 2 inches
- Faster data offload via Bluetooth 5.0
- Water detect feature indicates when logger was out of the water (MX801)
- Barometric pressure sensor included (MX802)
- Connect two sensors to one logger to get measurements like salinity adjusted DO directly, with no need for post-processing
- Guided calibration ensures accurate data
- User-replaceable batteries
Specifications
MX801 and MX802
Operating Range
-40° to 50°C (-40° to 122°F), cannot be frozen in ice
Radio Power
1 mW (0 dBm)
Transmission Range
Approximately 30.5 m (100 ft) line-of-sight
Wireless Data Standard
Bluetooth 5
Number of sensors that can be connected
2
Maximum Cable Length
120m (400 ft)
Logging Rate
5 second to 18 hours
Logging Modes
Fixed interval (normal or statistics), burst, or multiple intervals with up to 8 user-defined logging intervals and durations, with pause and repeat options
Start Modes
Immediate, next interval or date & time
Stop Modes
Memory full, never stop (overwrite oldest data), date & time, or after a set logging period
Water Detect
Events are logged when logger is submerged or removed from the water (MX801 only)
Time Accuracy
±1 minute per month 0° to 50°C (32° to 122°F)
Battery
Four AA, 1.5 V lithium batteries, user replaceable
Battery Life
With W-CTD or W-CT sensors: 2 years, typical with 1-minute logging interval or slower
With W-DO sensor: 1-year, typical with 5-minute logging interval or slower
Faster logging or statistics sampling intervals, entering burst logging mode, excessive readouts, and remaining connected with the app will impact battery life
Memory
730,000 measurements, divided between channels (4 Mbyte memory)
Data Download Time (with Bluetooth 5+ devices)
Full memory: Approximately 3.5 minutes
120,000 measurements: 1 minute
May take longer the farther the device is from the logger
Barometric Pressure (MX802 only)
Measurement & Calibrated Range
66 to 107 kPa (9.6 to 15.5 psia), -20° to 50°C (-4° to 122°F)
Accuracy*
Typical error: ±0.2 kPa (0.029 psi)
Maximum error: ±0.5 kPa (0.073 psi)
Resolution
<0.01 kPa (0.0015 psi)
Pressure Response Time**
<1 second to 90% at a stable temperature
Contribution to Water Level Accuracy***
Typical error: ±0.075% FS, 0.3 cm (0.01 ft) water
Maximum error: ±0.15% FS, 0.6 cm (0.02 ft) water
MX801 & MX802 Specs, continued:
Dimensions
Logger diameter: 4.14 cm (1.63 inches)
Length without sensor: 20 cm (8 inches)
Length with W-CTD sensor: 36 cm (14 inches)
Length with W-CT sensor: 33 cm (13 inches)
Mounting loop: 12.7 x 22.6 mm (0.5 x 0.89 inches)
Weight
MX801 Logger Head Only
224 g
7.90 oz
MX802 Logger Head Only
226 g
7.97 oz
Wetted Materials
Logger: PVC housing with polyester film label, PET sensor connector end cap and mounting handle with EPDM and Buna-N O-rings, passivated 316 stainless steel hardware rated for use in saltwater; MX802 also has ePTFE vent
Collar: HDPE, titanium screws
Note: logger should be mounted so that no metal parts of the logger are in contact with other metals
Depth/Environmental Rating
MX801: IP68; waterproof to 100m (with sensor(s) attached)
MX802: IP67, NEMA 6; Weatherproof (with cable or Termination Plug attached); this model is not waterproof
* Pressure Accuracy: Absolute pressure sensor accuracy includes all sensor drift, temperature, and hysteresis-induced errors.
** Changes in Temperature: Allow 20 minutes in water to achieve full temperature compensation of the pressure sensor. There can be up to 0.5% of additional error due to rapid temperature changes.
***Water Level Accuracy: With accurate reference water level measurement, known water density, and a stable temperature environment. System Water Level Accuracy equals the sum of the Barometric Water Level Accuracy plus the selected CTD sensor Water Level Accuracy.
Water Data Loggers
