Fluke Biomedical 07-621 - Manual (Page 8)

Nuclear Associates 07-621
Operators Manual
1-4
When attempting luminance readings, avoid casting shadows upon the subjects when those subjects are
reflecting objects (i.e., not light sources).
Conversion factors are shown below for other units of measurement.
cd/m2 = Candela/m
2
= Nit
lux = footcandles x 10.8
footcandles = .093
cd/m
2
(Nit) = footlamberts x 3.43
footcandles = cd x .292
m
2
1.6 Optional Equipment: Fiber-Optic Probe (Model 07-634)
This (optional) attachment is designed for use with Model 07-621 Photometer. It reads brightness of self-
luminant objects such as diffuse lighting screens, video monitors, signs, etc. Small areas (3 mm or 1/8
inch) can be measured and otherwise inaccessible areas can be reached.
Each probe is calibrated to be compatible with the photometer. Only use it with the meter that has been
calibrated with the probe. Recalibration is recommended when it is desired to make calibrated
measurements with another probe/photometer combination. The calibration unit of luminance
measurements with the probe is footlamberts. Mount the probe on the meter by first removing the turret
supplied. Place the probe's turret flat on top of the meter and tighten the thumbscrew snugly, but do not
over-tighten. To use, hold the Fiber-Optic probe against the surface to be measured, and operate the
photometer according to its instructions.
If the front of the probe is not flush with the surface, background light may distort the reading.
Things to Avoid: Do not bend the probe sharply or force it beyond the point to which it easily bends.
Avoid scraping the tip of the probe and scratching the fibers. Do not attempt to loosen the threaded
portion of the probe or the locking ring; otherwise, calibration will be affected.
1.7 Batteries
Four 1.5V, Type A- 76 alkaline button cells, or silver oxide types, MS-76, 10L 14, RW-42, 357.
When the batteries are weak, the LO BAT signal on the display will light after the Measure control is
released. If LO BAT stays lit with the display, change the batteries. If LO BAT light intermittently, it is only
a warning.
To change the batteries, loosen the battery door screw with a coin. Handle the new batteries with tissue
paper to avoid corrosion of the contacts. Replacement battery types are listed under Specifications.
Cold temperatures may temporarily cause the battery voltage to drop, thereby lighting LO BAT.
If the instrument will not operate, clean all batteries and contacts, as most problems are caused by poor
electrical connections. Also observe proper battery polarity (+, -).