Page 212 - Sensors and Control Systems in Manufacturing

FIGURE 3.52 Fiber Optics in Sensors and Contr ol Systems 173
Photodyne 9XT
optical source
driver. (Courtesy
3M Corporation)

work-crew environment. The unit is powered from two rechargeable
nicad batteries or from line voltage. The LED series is suited for mea-
surement applications where moderate dynamic range is required or
where coherent light should be avoided. The laser modules are used
for attenuation measurements, requiring extreme dynamic range or
where narrow spectral width and coherent light are required. The
laser modules are the most powerful source modules available.

3.16.1 Power Meters
Optical power meters are commonly used to measure absolute light
power in dBm, Figure 3.53. For dBm measurement of light transmis-
sion power, traceable calibration of fiber-optic power meters is essen-
tial. A fiber-optic power meter is also used with an optical light source
for measuring relative power levels in dB. Alternatively, some users
may prefer an integrated two-way Test Loss Set (TLS), or a simple
Loss Test Set (LTS).
The Photodyne 2285XQ fiber-optic power meter (Fig. 3.54) is a
low-cost optical power meter for general-purpose average-power