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A single instrument enables measurement of the three types of radiation that are of most interest: visible (Lux), thermal radiation and ultraviolet. The 774 also measures temperature in °C or °F.
Thermal Radiation (IR)
The measurement of thermal radiation (shown as W/m2 or btu/hour/ft2)
allows the user to estimate how much solar heat is coming through windows, check
the performance of heat reflecting films, measure the heating effect of lamps on
objects etc.
Visible Light
The amount of visible light is important, not only to check illumination in work
areas, galleries etc. but also to control damage to light sensitive objects that
is also caused by normal light. Measurements can be displayed as Lux or
Foot-candles.
Ultraviolet (UV)
For many years it has been recognised that one of the major causes of damage to
museum objects and other sensitive objects, soft furnishings etc. is the fading
and rotting effect of light on the object. The most damaging part of the
illumination is its ultraviolet 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 774,
measurements can be taken of the proportion of UV present (mW/lumen), the total
amount of UV (mW/m2).
Data Logging (version 774C only)
The optional data-logging function enables 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 then be transferred to a computer by a wireless
infra-red link (IrDA compatible). Many modern computers have an infra-red
interface built in; for those that do not, adapters are available. When logging
data the 774 can be turned off to save power and the built in clock will turn
the unit on whenever a reading needs to be taken, this enables a 774 to be left
taking readings for months at a time. Software is provided to display the
measurements and save the logged data in CSV format that can be accessed and
displayed by many programs (e.g. Microsoft Excel).
Easy to use
Much trouble has been taken to make the 774 as easy to use as possible. 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 damage is done 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 20 mW/m2.
| Visible wavelength range | 400-700 nm (CIE response). No correction required for different light sources. |
| Visible power range | 0.1 - 200,000 Lux (0.1 - 20,000 Foot-candles) |
| UV wavelength range | 300 - 400 nm |
| UV power range | 2 - 50,000 mW/m² |
| UV proportion range | 0 - 10,000 µW/Lumen |
| Thermal radiation sensor | Bismuth/Antimony thermopile with KBr window |
| IR/Thermal wavelength range | 350 nm - 40 µm |
| Thermal radiation range | 0-1000 W/m² |
| Display resolution | 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 µW/Lumen Temperature: 0.1°C or °FIR: 0.1 up to 100 then 1 |
| Accuracy | Visible: 5% ±1 displayed digit IR: 5% ±10 W/m2 UV: 15% ±1 displayed digit Temperature: ±0.5°C (±0.9°F) |
| Angular response (Light, UV & IR) | Cosine |
| 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 (774C only) | 10,900 readings of all 4 parameters |
| Computer Interface (774C only) | IrDA compatible wireless infra-red link. |
| Date functions | Display as day-month-year or month-day-year. Fully Year 2000 compliant. |
| Batteries | 2 off 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 for 774C (if requested) | 4.0-5.2V DC, 100mA A connection for an external supply is provided to special order at extra cost. |
| Operating Temperature | 0-50°C |
| Dimensions | 150 x 65 x 25mm 5.9 x 2.5 x 1 inches Including IR/Temperature probe |
| Weight | 165 g (5.6 oz) with batteries. |
Environmental Monitor Type 774,
measures visible light (Lux or Foot-candles), UV light (mW/m² and µW/lumen,
IR-light and temperature (°C or °F) - at the moment not available! |
730,- € |
Environmental Monitor/Logger Type 774C, as above with data logging capacity
for over 10000 readings of all 4 parameters, with wireless infra-red interface and Windows software - at the moment not available! |
904,- € |
IrDA adapter for serial Com port RS232 or USB-port (please specify) |
24,- € |
Universal Mains power supply (100 - 240V). Note: The instruments are supplied without a connection for an external supply unless specifically requested. External power connection (not normally required) |
mains adaptor 25,- € mains connection 35,- € |
| Order/Contact |
