Industrial Fiber Optics IF-FOM, Руководство оператора

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– 10 –
1018.eps
ZERO
FIBER OPTIC TEST SET
DISPLAY
SELECTOR
SWITCH
ON/OFF
SWITCH
20 μ
W
200
μ W 2 mW
20 mW
Industrial Fiber Optics
LED
ACTIVATION
WAVELENGTH
( λ )
650 nm
850 nm
LED TURNS OFF
AFTER 10 MIN.
DETECTOR
Optical
Energy
Remote Optical
Source
6. Turn the optical transmitter or source on and make any adjustments necessary to
set the data rate or power level.
Observe proper safety precautions as outlined in
the SAFETY section of this manual.
If you are using the built-in LED optical source
in the Fiber Optic Test Set, push the “LED ACTIVATION” button. Allow one
minute for the source to stabilize.
7. Observe the LCD display for an indication or non-zero reading. If the reading is
zero or very low, rotate the ‘”DISPLAY SELECTOR SWITCH” counter-clockwise
(more sensitive scale) until the display gives a maximum reading without
over-ranging. Note the reading in µW or mW and compare it to the expected
power level. Optical power is often specifi ed in units of dBm which uses a more
compressed scale to indicate wide variations in power. Table 4 shows some
common units of dBm and the equivalent power in watts. For an explanation of
the dBm scale, see the section titled Logarithms/dB measurement units.
8. If the reading is much less than expected, possible causes are:
• Lossy or bad connection at transmitter or optical source-check connector ends
for cleanliness and scratches or other damage.
• Bad splices or connector-to-connector interfaces.
• Fiber broken inside cable jacket
9. Turn off the Fiber Optic Test Set by pressing the “ON/OFF” switch. Remove all
cable ends from the test set receptacles and replace the protective caps.
Figure 2. Diagram showing test set
connected to measure optical power