OPERATION
General Operating Procedures
4_03 OMH-6722B 11
CHAPTER 2
• Use the WAVELENGTH LEFT and RIGHT arrow buttons to select the digit on the
Wavelength display that will be controlled by the WAVELENGTH UP and DOWN arrow
buttons. The selected digit will flash.
• Use the WAVELENGTH UP and DOWN arrow buttons to increment or decrement the
selected digit. If no buttons are pressed in three seconds, the displayed wavelength will be
locked in and the digit will stop flashing.
• Commonly used wavelengths may be stored or retrieved by using the WAVELENGTH BLUE
SHIFT, STORE λ, λ1,λ2,λ3, and λ4 buttons as described in Chapter 2 of the OMM-6810B
manual.
Zeroing
The ZERO function is used to remove the effects that
erroneous room light has on the wavelength and power
measurement. It is important to zero the OMM-6810B with the
OMH-6722B attached before taking measurements. This is
especially true for low input power applications or in cases of
high ambient light intensity. When measuring lower power
levels, avoid letting background radiation into the measurement head.
Pressing the DISPLAY
ZERO button when the DISPLAY ZERO indicator is not
lighted starts the zeroing process. While zeroing the "0" digit
walks across both
displays and the DISPLAY
ZERO indicator flashes. When zeroing is complete the
DISPLAY
ZERO indicator is illuminated. Pressing the DISPLAY ZERO button
when the DISPLAY
ZERO indicator is illuminated disables the effects of the zero.
The procedure for zeroing the instrument is described below.
• The beam from the optical source should be blocked at the source or turned off.
Note: If a beam stop is used, it should be positioned as close to the source as possible to
allow the
maximum collection of background "noise". If the entry aperture to the
OMH-6722B is blocked instead, the zeroing function will not work properly. This is
especially true for low power applications or in areas of high background light.
• If the DISPLAY ZERO indicator is illuminated, press the DISPLAY ZERO button once to
disable the existing compensation factors.
• Press the DISPLAY ZERO button. While zeroing, the "0" digit walks across the display and
the DISPLAY ZERO indicator flashes. When zeroing is complete the DISPLAY ZERO
indicator is lighted. The process takes about 15 seconds.
• Allow the beam to enter the aperture of the head. Accurate measurements are displayed.
Note: If the ambient environmental conditions change, e.g. the room lights are turned on or
off, the instrument must be re-zeroed to maintain its accuracy.
• Pressing the DISPLAY ZERO button again disables the compensating factors and the
DISPLAY ZERO indicator is turned off.
