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Visible (Lux), Thermal Radiation and Ultraviolet Meter with Datalogger
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 recognized 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
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
20mW/M2.
|
Specifications |
| Visible
wavelength range: |
400-700nM
(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 mW/Lumen |
| Thermal
radiation sensor: |
Bismuth/Antimony
thermopile with KBr window |
| IR/Thermal
wavelength range: |
350nM
- ~40µM |
| 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 mW/Lumen
Temperature: 0.1°C or °FIR: 0.1 up to 100 then 1 |
| Accuracy: |
Visible:
5% ±1 displayed digit
IR: 5% ±10W/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: |
10,900
readings of all 4 parameters |
| Computer
Interface: |
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 (If available): |
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: |
165g
(5.6 oz) with batteries. |
View Comparison Chart for:
Environmental Quality Meters
Ultra Violet Light Meters
Warranty Information
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