1. Overview
The UNI-T UT330+ series Digital Temperature Humidity Meters are designed with a high-precision sensor and a super-low power consumption microprocessor. These meters offer high accuracy, manual and automatic data storage, USB data transfer, USB power supply, backlight alarm, real-time display, and low power consumption. They are suitable for use in various environments including factories, laboratories, research institutes, food and health facilities, and for environmental protection.
The product features include higher accuracy, a wider temperature measurement range, increased data storage capacity, USB/battery dual-mode power supply for convenience, high and low temperature limit screen flashing alarms, and PC software for data transmission and real-time data functions.
Figure 1: UNI-T UT331+ and UT332+ Digital Thermometer Hygrometer
Video 1: Overview of UT331+ and UT332+ features and applications.
2. Safety Information
▲ Warning: This section identifies conditions and actions that pose hazards to the user. To avoid electrical shock or personal injury, follow these guidelines:
- Inspect the case before using the meter. Do not use if it appears damaged (cracks, missing plastic).
- Replace batteries as soon as the battery indicator appears.
- Do not use the meter if it operates abnormally. Protection may be impaired.
- Do not operate the meter around explosive gas, vapor, or dust.
- When servicing, use only specified replacement parts.
- Do not use the meter with any part of the case or cover removed.
- Do not clean the sensor with water. Close the protective sensor cover when not in use to avoid damage.
- Never charge the battery.
- Use only approved alkaline AAA 1.5V batteries. Pay attention to '+' and '-' marks.
- Close the sensor cover and remove batteries if the meter is not used for a long time.
3. Meter Description and Components
The meter consists of several key components for accurate temperature and humidity measurement and data management.
Figure 2: Appearance Introduction and Labeled Parts
Meter Structure
- Protective cover of sensor: Turn to open or close.
- Display screen: Shows readings and status.
- Power on/off button: To turn the device on or off.
- MAX/MIN button: Displays maximum/minimum values. Long press to exit.
- STORE button: Saves data.
- SETUP button: Enters setup mode. Used with ▲▼ buttons.
- Backlight button: Short press to turn on/off backlight. Long press to turn on/off alarm.
- HOLD button: Freezes displayed readings. Press again to exit. (Also used as ▼ button).
- RECALL button: Views stored data. Used with ▲▼ buttons.
- ENTER/DP button: Dew-point temperature and wet bulb temperature selection key (also used as confirm button).
Display Screen Elements
The LCD displays various information including:
- HI/LO: Upper/Lower limit indicators
- DEW POINT: Dew-point temperature
- WET: Wet-bulb temperature
- LOG: Storage group number
- MAX/MIN: Maximum/Minimum value
- HOLD: Data hold indicator
- %RH: Humidity unit
- °C/°F: Temperature units
- Time display zone
- Low battery/USB power supply indicator
- Alarm icon
- Auto power off icon
4. Setup
To enter setup mode, short press the SETUP button. The first page is unit setting. Press SETUP repeatedly to cycle through settings. If no button is pressed for 15 seconds, the meter will exit setup mode.
Setup Cycle Sequence:
Measuring state → Temperature unit setup → Time interval setup → Temperature & Humidity Upper Limit Alarm Setup → Temperature & Humidity Lower Limit Alarm Setup → Sleep time setup → System time setup → Temperature & Humidity Offset setup → Measuring state.
Performing Setups:
- Setting Temperature Unit: Short press SETUP. Use HOLD/▲ or MAX/MIN/▼ to select °C or °F.
- Setting Time Interval (for Auto Storage): Short press SETUP to switch to time interval mode (