HOBO Pendant Temperature Data Logger (UA-001-xx) Manual
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Product Overview
The HOBO Pendant Temperature Data Logger is a waterproof, one-channel logger with 10-bit resolution. It can record up to approximately 6,500 (8K model) or 52,000 (64K model) measurements or internal logger events. The logger utilizes a coupler and optical base station with a USB interface for launching and data readout by a computer. Onset software is required for logger operation.
Specifications
| Specification | Details |
|---|---|
| Measurement Range | -20° to 70°C (-4° to 158°F) |
| Alarms | High and low alarms can be configured for total amount of contiguous or non-contiguous time outside of user-defined limits between -20° and 70°C (-4° to 158°F). |
| Accuracy | ±0.53°C from 0° to 50°C (±0.95°F from 32° to 122°F), see Plot A |
| Resolution | 0.14°C at 25°C (0.25°F at 77°F), see Plot A |
| Drift | Less than 0.1°C/year (0.2°F/year) |
| Response Time | Airflow of 2 m/s (4.4 mph): 10 minutes, typical to 90% Water: 5 minutes, typical to 90% |
| Time Accuracy | ±1 minute per month at 25°C (77°F), see Plot B |
| Operating Range | In water/ice: -20° to 50°C (-4° to 122°F) In air: -20° to 70°C (-4° to 158°F) |
| Water Depth Rating | 30 m from -20° to 20°C (100 ft from -4° to 68°F), see Plot C |
| NIST Traceable Certification | Available for temperature only at additional charge; temperature range -20° to 70°C (-4° to 158°F) |
| Battery Life | 1 year typical use |
| Memory | UA-001-08: 8K bytes (approx. 6.5K readings) UA-001-64: 64K bytes (approx. 52K readings) |
| Materials | Polypropylene case; stainless steel screws; Buna-N o-ring |
| Weight | 15.0 g (0.53 oz) |
| Dimensions | 58 x 33 x 23 mm (2.3 x 1.3 x 0.9 inches) |
| Environmental Rating | IP68 |
| Compliance | CE Marking (European Union) Passed RTCA DO160G, part 21H |
Graphical Data Descriptions
Plot A: Accuracy/Resolution vs. Temperature
This plot displays the logger's accuracy and resolution in degrees Celsius across a temperature range from -20°C to 70°C. Two lines are shown: one for accuracy and one for resolution. Accuracy is generally higher (closer to zero) at moderate temperatures (0°C to 50°C) and decreases at colder temperatures. Resolution is shown as a single value across the range.
Plot B: Timebase Error vs. Temperature
This plot illustrates the timebase error in parts per million (PPM) as a function of temperature, ranging from -20°C to 70°C. The plot shows that timebase error is minimal around 25°C and increases negatively as temperature decreases, and slightly positively as temperature increases.
Plot C: Waterproof Range vs. Temperature
This plot indicates the logger's waterproof depth rating in meters against temperature in degrees Celsius. The depth rating is 30 meters (100 feet) from -20°C up to 20°C. Above 20°C, the waterproof depth rating decreases.
Connecting the Logger
The HOBO Pendant logger requires one of the following to connect to a computer:
- Pendant Optic USB Base Station & Coupler (BASE-U-1) with HOBOware 2.1 or later.
- Optic USB Base Station (BASE-U-4) or HOBO Waterproof Shuttle (U-DTW-1) with coupler (COUPLER2-A) and HOBOware 2.2 or later.
It is advisable to avoid connecting at temperatures below 0°C (32°F) or above 50°C (122°F).
Connection Steps:
- Plug the USB connector of the base station into an available USB port on your computer.
- Insert the logger and the base station into the coupler, aligning any ridges with grooves.
- For BASE-U-1, ensure the logger is in the coupler end with the magnet and align ridges.
- For BASE-U-4 or HOBO Waterproof Shuttle, insert the optical end of the base station into the D-shaped end of the coupler and align the logger's ridge with the coupler's groove.
- If using the HOBO Waterproof Shuttle, briefly press the coupler lever to activate base station mode.
- Allow a few seconds for the computer to detect the new hardware if it's the first connection.
- Use the HOBOware software to set up alarms, launch, and read out the logger. Data can be read out or status checked while logging continues, or the logger can be stopped manually or allowed to fill its memory. Refer to the HOBOware user's guide for detailed instructions.
Important: Do not cover the logger's optical communication window with labels or stickers, as this may interfere with communication.
Triggered Start
The logger can be configured to start logging using a magnet in the coupler.
- Launch the logger using HOBOware, selecting "Using Coupler". Remove the logger from the coupler.
- Take the logger, an empty coupler, or a strong magnet to the deployment location.
- When ready to start logging, insert the logger into the coupler (or place it next to a strong magnet) and remove it after three seconds.
- Verify that the logger's status light blinks at least every four seconds.
Important: Any magnet can trigger a start, which could lead to premature logging. Keep the logger away from strong magnetic fields until ready to deploy. The logger will not launch if the base station is in the coupler.
Sample and Event Logging
The logger records two types of data: samples (measurements at logging intervals, e.g., temperature every minute) and events (occurrences like "Bad Battery" or "Host Connected" that help track logger activity).
Operation Indicators (LEDs)
The logger's front LEDs indicate its operational status:
- Logging faster than four seconds: Lights blink at the logging interval. Green for OK temperature, Red for high alarm, Blue for low alarm.
- Logging at four seconds or slower: Lights blink every four seconds. Green for OK temperature, Red for high alarm, Blue for low alarm.
- Awaiting start (configured for Interval, Date/Time, or Using Coupler): Green light blinks once every eight seconds until logging begins.
Protecting the Logger
The logger can be damaged if its water depth rating is exceeded. The rating is approximately 30 m (100 ft) at temperatures below 20°C (68°F), decreasing in warmer water (refer to Plot C).
Do not store the logger in the coupler when not in use, as it consumes more power and can drain the battery prematurely. Keep the logger away from magnets to prevent false events or premature starts.
Periodically inspect the desiccant pack in the logger's cap. If it is not bright blue, it needs drying. Remove the pack and dry it in a warm, dry location until blue, or in a 70°C (160°F) oven for two hours.
Static Electricity Warning: To prevent data loss from static discharge, transport the logger in an anti-static bag and ground yourself before handling.
Desiccant Maintenance Schedule:
| Temperature Range | Maintenance Schedule |
|---|---|
| Less than 30°C (86°F) | Approximately once per year |
| 30° to 40°C (86° to 104°F) | Approximately every six months |
| Over 40°C (104°F) | Approximately every three months |
Configuring Alarms
Alarms can be configured to flash high or low LEDs when the sensor reading falls outside user-defined limits.
- In the HOBOware "Launch Logger" window, click the "Alarms" button to open the "Configure Alarms" window.
- Select the check box for High Alarm and/or Low Alarm, and enter the desired threshold values using the sliders or by typing.
- Specify the number of out-of-range samples required to trigger each alarm.
- Choose an Alarm Mode:
- Cumulative: Alarm triggers after a specified number of samples logged outside the allowed value, regardless of consecutiveness.
- Consecutive: Alarm triggers only when the value remains outside the allowed value for a specified duration. The count resets if the value returns to the normal range before triggering.
- Click "OK" to save the settings.
Battery Information
The logger uses one 3-Volt CR-2032 lithium battery. Battery life depends on temperature and logging frequency. A new battery typically lasts one year with logging intervals greater than one minute. Extreme temperatures or logging at one-second intervals can significantly reduce battery life, potentially to as little as two weeks.
Battery Replacement Procedure:
You will need a small Philips head screwdriver and silicone-based O-ring grease (e.g., Parker Super-O-Lube). Ensure the logger is clean and dry before opening.
- Ground yourself to avoid electrostatic discharge. Handle the circuit board by its edges.
- Remove the two screws securing the end cap and remove the cap.
- Inspect the desiccant pack in the cap. If not bright blue, dry it as described previously.
- Gently tap the case to loosen the circuit board and carefully remove it.
- Using a small, nonmetallic blunt instrument, push the old battery out of its holder.
- Insert a new CR-2032 battery with the positive side facing up.
- Carefully return the circuit board and label to the case, aligning it with the case grooves, ensuring the battery faces the ridged side.
- Remove the O-ring from the end cap. To do this safely, form a loop with the O-ring using your fingers and slide it off.
- Inspect the O-ring for damage and replace if necessary (replacement parts kit UA-PARTSKIT available).
- Apply a small amount of silicone-based grease to the O-ring, ensuring it is fully coated without grit or debris.
- Place the lubricated O-ring back into the end cap groove, ensuring it is seated correctly, not pinched or twisted, and free of debris. This is crucial for a waterproof seal.
- Apply a small amount of silicone grease to the inside rim of the logger case, especially around screw holes, avoiding circuitry. Ensure no excess lubricant or debris is present.
- Check that the desiccant pack is properly placed in the cap.
- Carefully push the end cap onto the lubricated case until screw holes align. Visually confirm the O-ring creates a uniform seal.
- Re-fasten the screws. Tighten until snug, but do not overtighten to avoid distorting the housing.
Battery Warning: Do not cut open, incinerate, heat above 85°C (185°F), or recharge the lithium battery. Improper handling can cause explosion. Dispose of batteries according to local regulations.
