Environmental Meter | RH / Temp / Light (UV & Lux)

It is recognised that a major cause of damage to museum works of art can be in the light illuminating a room (Ultra violet and visible radiation), with the most damaging being the UV content.To enable curators and conservators to monitor these levels we offer a proven range of instruments.


With regard to light, this meter measures:

  1. Proportion of UV present (µW/Lumen)
  2. The total amount of UV (µW/M²)
  3. The amount of visible light present (Lux).
Allowing you to take action when needed: The amount of UV should be as small as possible, and in general should not exceed 20µW/M² or 75µW/Lumen. Normal museum light levels should be limited to 150-250 Lux. Once measurements have been observed action can be taken, light levels altered, if necessary UV filters fitted to display cases, windows and fluorescent tubes.

This single instrument measures:

  1. Humidity (RH) + Absolute humidity (AH)
  2. Temperature (Degrees C/F) + Heat Index (HI) and Humidex (Hmdx) (further information in 'Specification' tab below)
  3. Ultra Violet (UV)
  4. Visible Light (LUX)

The large 128x64 OLED Display with automatic brightness control has an easy to use menu system to select more advanced functions.

Data Logging functions (available on 684-765C) enable over 10,000 readings of all four parameters to be automatically taken at selectable intervals (every 10 seconds to 1 hour). The saved data can be transferred to a computer by a USB connection. Software is provided to save the logged data in a CSV format that can be accessed and displayed by many applications.

Further technical information in 'Specification' tab below

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Code Description Image Pack Size Price Stock QTY
P684-765 684-765 Environmental Meter for Temp., RH, UV, and Lux
P684-765 684-765
Pack Size: Each Price: £704.00 ex VAT In Stock
P684-765C 684-765C Environmental Monitor with Data Logging
P684-765C 684-765C
Pack Size: Each Price: £835.00 ex VAT In Stock
P684-7657 684-7657 RH Test Kit for 684-765 Environmental Monitor
P684-7657 684-7657
Pack Size: Each Price: £166.00 ex VAT Low Stock
P684-7648 684-7648 Recalibration for Environmental Monitors
P684-7648 684-7648
Pack Size: Each Price: Call Made to Order

Visible wavelength: 400-700nM
Visible power: 0.1-200,000 Lux
UV wavelength: 300-400nM
UV power:2-50,000 µW/M²
UV proportion:0-10,000 uW/Lumen
RH Range:0-100%
Display Resolution LUX: 0.1 up to 100 then 1. footcandles: 0.1 up to 100 then 1. UV: 0.1 up to 100 then 1. proportion of UV 1 uW/Lumen. Temperature: 0.1°C or °F. RH: 0.1%
Accuracy: Light & UV: 5% +/- 1 displayed digit. Temperature: +/- 0.5°C (+/- 0.9°F). RH: +/-2.5% 0-90% otherwise +/-5%
Data logging intervals: 10 sec (8 days). 1 min (49 days). 10 mins (486 days).
Data logging capacity: 70,000 readings of all 4 parameters
Batteries: Rechargable NiMH
Dimensions: 150 x 65 x 25mm (including probes)
Weight: 165g

Heat Index (HI) and Humidex (Hmdx) These are indexes that combines air temperature and relative humidity, in shaded areas, to posit a human-perceived equivalent temperature, as how hot it would feel if the humidity were some other value in the shade. The result is also known as the "felt air temperature", "apparent temperature" or "feels like". Heat Index was developed in the USA, Humidex in Canada.

Absolute humidity (AH) is displayed with RH.

Calibration recommended every 12-24 months for accurate readings.

Software is provided to save the logged data in a CSV format that can be accessed and displayed by many applications (e.g. Microsoft Excel). Maximum and minimum values and their time measurement are displayed for each parameter. A calibration kit is available for user calibration of the RH sensor using saturated salt solutions.

Operation: The appropriate button is pushed depending on the measurement required and the reading taken. The environmental monitor automatically turns off 10 seconds after the last reading to preserve battery power. If a button is held down for over 5 seconds, the monitor enters continuous monitoring mode until another button is pressed.

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