New Focus 1480, User Manual, Page: 8 / 20

8 • Operation NEW FOCUS, Inc.
9.
Connect your optical fiber to the connector on the
detector module.
10.
When finished using the module, turn off the
power to preserve battery life.
If any of these steps present problems or you would
like more information, please consult the remainder of
this manual.
Checking the Battery and Offset Voltage
The battery and offset voltage should be checked
regularly to ensure proper functioning of the detector.
1.
Turn on the module using the power switch.
2.
Connect the “Bias Monitor” port to a voltmeter.
3.
Press and hold the “Batt Chk” button and observe
the bias-monitor output. The photodiode bias
voltage is momentarily applied to the “Bias
Monitor” SMA connector. A reading of 5 V on this
connector is typical with a new battery; the
battery should be replaced when the voltage
reaches 3.5 V.
4.
Release the “Batt Chk” button and observe the
voltage level on the voltmeter. Without an optical
input, this voltage is the DC offset plus dark
current. This “dark voltage” should be less than
10 mV.
5.
If needed, keep the voltmeter connected to the
module to optimize coupling to the fiber.
Replacing the battery
1.
Turn off the module and remove the two screws
on the back panel with a Phillips screwdriver. (See
Figure 1 on page 6.)
2.
Remove the back panel and replace the battery.
3.
Replace the back panel.
1480 FC Det revA.fm Page 8 Monday, March 13, 2000 2:55 PM