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This single environmental instrument measures the four parameters that cause most damage to buildings, valuable objects, documents, etc: ultraviolet and visible light, humidity and temperature.
The 765 measures and displays visible light (Lux or Foot-candles), UV light (mW/M² or µW/lumen), temperature (°C or °F) and humidity (%RH). This is the world standard instrument for museums, art galleries conservators or any application requiring a controlled environment.
The 765C (with data logging) is the same as 765 with data logging capacity for over 70,000 readings of all 4 parameters. No special software is required, logged information is stored on an internal USB Flash disc and the data can be downloaded onto a PC and viewed with any spreadsheet (Excel etc). A free application (RView) is also available for download that displays the data as a zoomable graph that can be saved as an image for inclusion in documents and/or printed.
For many years it has been recognized that one of the major causes of damage to museum objects and other antiquities is the fading and rotting effect of light on the object. The most damaging part of the illumination is its ultraviolet (UV) content.
Since 1976 Littlemore Scientific (ELSEC) has been providing instruments that enable the conservator to measure the UV content of light and thereby protect valuable exhibits. Using the 765, measurements can be taken of the proportion of UV present (mW/lumen), the total amount of UV (mW/M²), the amount of visible light present as Lux or Foot-candles. Temperature can be measured in °C or °F, humidity is shown as % Relative Humidity (%RH) and dew point. The displayed units can easily be changed by the user.
Min/max values and their time of measurement are displayed for each parameter.
Anyone can take measurements straight out of the box with little, if any, reference to the instruction manual. The appropriate button is pushed depending on the measurement required and the reading is taken. The unit automatically turns off 10 seconds after the last reading unless a button is held down for over 5 seconds, this causes continuous measurements to be taken until another button is pressed. The large 8 line display enables an easy to use menu system to select the more advanced functions, change units etc.
Units of measurement for UV
Traditionally UV has been measured in museums as the proportion of ultraviolet present. This result is useful for checking a particular lamp or window because the proportion of UV does not change with the distance from the light source. Using a simple rule, the amount of UV on an object can be limited (it is usual to arrange that the proportion of UV should not exceed 75mW/lumen in museums). The actual amount of damage done is determined by the total amount of UV falling on the object, so it is useful to be able to measure this directly, especially if non standard amounts of illumination are required. The amount of UV should be as little as possible but in general should not exceed 20mW/M².
A Lux readout is provided to control illumination and limit damage done by visible light. Normal museum light levels should be limited to 150-250 Lux.
Dimensions: 5.9" x 2.5" x 1" (150 x 65 x 25 mm) including RH/Temperature probe
Weight: 5.6 oz (165 g) with batteries.
|Visible Wavelength Range:||400 to 700 nM (CIE response). No correction required for different light sources.|
|Visible Power Range:||0.1 to 200,000 Lux (0.1 to 20,000 Foot-candles)|
|UV Wavelength Range:||300 to 400 nm|
|UV Power Range:||2 to 50,000 mW / sqm|
|UV Proportion Range:||8 to 10,000 mW / Lumen|
|RH Sensor:||Capacitive film type|
|RH Range:||0 to 100% RH|
Lux: 0.1 up to 100 then 1
Foot-candles: 0.1 up to 100 then 1
UV: 0.1 up to 100 then 1
Proportion of UV: 1 mW / Lumen
Temperature: 0.1°C or °F
Light and UV: 5% ± 1 displayed digit
Temperature: ±0.5°C (±0.9°F)
(Light & UV)
|Readout:||8 line graphical Liquid Crystal Display with automatic backlight|
Data Logging Time Intervals:
(Time Till Full)
|10 seconds (30 hours), 1 minute (7½ days), 10 minutes (75 days), 1 hour (454 days)|
|Data Logging Storage Capacity:||10,900 readings of all 4 parameters|
|Storage Resolution for Logged Data:||
Light & UV: 0.1% of saved value
Humidity: 0.5% RH
|Computer Interface:||IrDA compatible wireless infrared link.|
|Date Function:||Display as day-month-year or month-day-year.|
|Batteries:||2 alkaline AA type|
|Battery Life:||Approx. 100 hours continuous use or 12,000 readings taking 30 seconds each. Battery life will be less if the display backlight is used|
External Power Supply:
Unless specifically requested, the meter does NOT include a connection for an external supply.
|4.0 to 5.2V DC, 100 mA A suitable mains power supply can be provided as an optional extra (please specify mains voltage required).|
|Operating Temperature:||32 to 122°F
0 to 50°C
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