Frequently Asked Questions (FAQ) for Fujita Electric Works KT-255U Thermo-Hygro Data Logger:

1. What is the KT-255U device?

The KT-255U is a compact thermo-hygro data logger with an integrated LCD display. It records ambient temperature and relative humidity over time for laboratory, storage, or transport monitoring applications.

2. What are its measurement ranges and resolutions?

Temperature: –40 °C to +80 °C with 0.1 °C resolution

Humidity: 5 %RH to 90 %RH with 1 %RH resolution

3. What are its accuracy specifications?

Temperature accuracy: ±1 °C over full range

Humidity accuracy: ±5 %RH over full range

4. How much data can it store and at what intervals?

The internal memory can hold up to 14 000 temperature readings and 14 000 humidity readings. Users can choose a sampling interval between 1 and 255 minutes to balance record length and data resolution.

5. How do I start and stop recording?

To start recording, press and hold the START/STOP button until “REC” appears on the LCD.

To stop and lock the log, press and hold the same button until “END” is displayed.

6. How can I change the sampling interval?

Power on the device.

Navigate to the “Interval” menu using the up/down arrows.

Select a value from 1 to 255 minutes.

Press OK to confirm and return to standby.

7. How do I set the date and time?

Enter the “Clock” menu.

Adjust year, month, day, hour, and minute with the arrow keys.

Press OK to save the settings.

8. Does the KT-255U have an alarm function?

Users can enable high- and low-value alarms for both temperature and humidity. When a threshold is exceeded, the LCD backlight flashes and an audible tone sounds to alert the operator.

9. How do I retrieve recorded data?

Connect the KT-255U to a PC via the supplied USB cable.

Launch the KTViewer software.

Click “Download” to transfer logged data to your computer.

10. What software is provided and which operating systems are supported?

The included KTViewer application runs on Windows XP, Vista, 7 and macOS 10.12 or later. It allows data download, graph plotting, report generation, and CSV/PDF export.

11. In what file format are the data exported?

Data are exported in standard CSV (comma-separated values), which can be opened in Excel or any text editor. PDF reports can also be generated directly from KTViewer.

12. How do I perform calibration?

Fujita recommends annual recalibration or after any mechanical shock. Calibration can be done by exposing the sensor to certified reference standards (e.g., salt-solution humidity chambers) and adjusting readings via KTViewer.

13. How should I clean and maintain the device?

Wipe the enclosure with a soft, damp cloth. Do not use organic solvents or immerse the unit in liquids. Store the logger in a clean, dry place when not in use.

14. How do I replace the battery?

Remove the rear cover.

Replace the CR2477 lithium cell with a fresh, same-type battery, ensuring correct polarity.

Reinstall the cover and confirm the clock setting.

15. What are the physical dimensions and power supply?

Dimensions: 90 mm × 15 mm × 34 mm

Weight: Approx. 45 g

Power: CR2477 lithium battery × 1 (test battery included)

16. What accessories are included in the package?

USB cable × 1

KTViewer software (CD-R) × 1

Flat-head screwdriver (for battery compartment) × 1

CR2477 lithium battery × 1

17. What are the recommended operating conditions?

Ambient temperature: –20 °C to +60 °C

Relative humidity: 10 % to 85 %RH

Atmospheric pressure: 700 to 1 060 hPa

18. In which applications is the KT-255U best suited?

Ideal for monitoring cold-chain logistics, server rooms, pharmaceutical storage, food production lines, museums, and research laboratories where precise temperature and humidity tracking is critical.

19. What is the device’s ingress protection rating?

The KT-255U housing meets IP54 standards, offering protection against limited dust ingress and splashing water.

20. What is the warranty and how do I get support?

Fujita covers the KT-255U under a 12-month warranty from the date of purchase. Technical support and calibration services are available through distributors as QTE Technologies (qtetech.com/en).