Illuminance Meter UNI-T UT381A, 0–400,000 lx, Bluetooth, CCF

UNI-T UT381A Illuminance Meter, 0–400,000 lx, Bluetooth, CCF

The UNI-T UT381A is a digital illuminance meter designed primarily for indoor light-intensity measurements in lux (lx) or foot-candles (fc). It provides a measurement range up to 400,000 lx, automatic ranging, MAX/MIN/AVG, Data Hold, storage for 99 readings and Bluetooth connectivity with the UNI-T iENV mobile app. Its rotatable, split probe provides flexible sensor positioning, while the CCF function supports measurements of coloured LED light sources.

Key specifications: 0–400,000 lx • resolution down to 0.01 lx • ±3% with a 2856 K standard light source • 99 records • Bluetooth / iENV • CCF

Key features and benefits

• Wide 0–400,000 lx measuring range – suitable for measuring both low and high indoor illumination levels.
• Automatic range selection – eliminates the need to select the measurement range manually.
• Three resolution levels – readings are displayed with 0.01 lx, 0.1 lx or 1 lx resolution depending on the range.
• CCF (Color Correction Coefficient) – R, G, B, Y, P and USER options are available for coloured LED measurements.
• Rotatable and split probe – allows the sensor to be positioned more conveniently relative to the light source.
• MAX/MIN/AVG and Data Hold – enables monitoring of maximum, minimum and average values and holding the current reading on screen.
• 99-reading memory – readings can be stored manually or recorded automatically at a selected interval.
• Bluetooth connection with the UNI-T iENV app – enables measurement data transfer to a smartphone, trend viewing and data export.
• Backlit LCD and over-range indication – improves readability in dim conditions and displays “OL” when the measurement range is exceeded.

Applications

The UT381A is suitable for indoor illuminance measurements in offices, laboratories, commercial premises, workplaces and other areas where light intensity needs to be evaluated. It can also be used during lighting installation, adjustment and maintenance, and for coloured LED measurements using the CCF function.

The meter is suitable for general users who need to evaluate illumination as well as technicians and specialists who require data logging and smartphone connectivity.

Compatibility and limitations

• Supports the UNI-T iENV application for iOS and Android devices.
• Measurement data can be transferred to the app via Bluetooth; the meter clock can also be updated through the phone connection.
• According to the manufacturer’s manual, Android 10 or later requires the location function to be enabled during Bluetooth connection.
• CCF options include R (red), G (green), B (blue), Y (yellow), P (purple) and USER. For white LEDs, the manufacturer specifies normal measurement without a colour correction coefficient.
• UNI-T specifies the UT381A for indoor use and does not recommend outdoor measurements in direct sunlight because sunlight may cause increased measurement deviation.

Technical specifications

Parameter	Value
Model	UNI-T UT381A
Product type	Digital illuminance meter
Illuminance measurement range	0–400,000 lx
Maximum value in fc mode	37,160 fc
Resolution, 0–99.99 lx (99.99 fc)	0.01 lx (0.01 fc)
Resolution, 100–999.9 lx (999.9 fc)	0.1 lx (0.1 fc)
Resolution, 1000–400,000 lx (up to 37,160 fc)	1 lx (1 fc)
Measurement accuracy	±3% when calibrated to a standard 2856 K light source; ±6% with other visible light sources
Measurement units	lx / fc
Conversion	1 fc = 10.764 lx
Automatic range selection	Yes
MAX / MIN / AVG	Yes
Data Hold	Yes
Color Correction Coefficient (CCF)	Yes
CCF selections	R / G / B / Y / P / USER
Display backlight	Yes
Bluetooth	Yes
Supported mobile app	UNI-T iENV
Internal data storage	99 readings
Automatic recording interval	1–59 s
Manual recording	Yes
Probe configuration	Integrated / rotatable / split
Real-time clock	Manually adjustable or updated through the phone app
Over-range indication	“OL”
Automatic power off	After approximately 10 min of inactivity; can be disabled
Low-battery indication	Yes; the meter powers off after the low-battery icon flashes for 10 s
Power supply	3 × 1.5 V AAA
Battery life	More than 100 h with alkaline batteries when Bluetooth and the backlight are off
Operating temperature	-10 °C to 50 °C
Operating relative humidity	<90% RH, non-condensing
Storage temperature	-20 °C to 70 °C
Storage relative humidity	<80% RH, non-condensing
Intended environment	Indoor
EMC standard	EN IEC 61326-1:2021
Manufacturer-listed compliance	CE, UKCA, RoHS
Dimensions	235 × 64.5 × 40 mm
Weight	Approx. 257 g, batteries excluded

Construction and controls

The UT381A features a backlit LCD and a spherical light sensor protected by a removable protective cap. The probe is rotatable and can be used in a split configuration, allowing the sensor to be positioned more conveniently with respect to the measured light source.

Dedicated controls are provided for unit selection, MAX/MIN/AVG, data recording, Data Hold, settings and Bluetooth operation.

Important operating and safety notes

• For low-level measurements below 10 lx, the manufacturer recommends fitting the protective cap and performing zero calibration before measurement.
• The white spherical sensor surface should be protected from scratches and contamination. Fit the protective cap when the meter is not in use.
• Do not use or store the meter in abnormally high temperature or humidity, flammable or explosive environments, or strong electromagnetic fields.
• Do not open the meter housing; servicing should be performed by qualified personnel.

Package contents

• UNI-T UT381A illuminance meter
• 3 × 1.5 V AAA batteries
• Strap