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Operations/Analysis Unit 4
Teledyne Analytical Instruments
A Business Unit of Teledyne Electronic Technologies
chemical background has changed. In some cases, TAI is
not able to duplicate the background your sample for
purposes of optically balancing the analyzer before shipment.
In these cases, it is necessary for you to screen for an
approximate balance, and to then electronically adjust R3 for
precise balance. To do so:
1. Reset R3 to its midpoint.
2. Re-screen the filter wheel, as necessary, to obtain a
measuring voltage within 10% of the reference voltage.
Every time a screen is added or removed from a filter, the
analyzer must be turned off, and the filter wheel removed
from the analyzer. When the filter wheel is replaced in the
analyzer, its rotational position is not critical, but the
white backing must face in the direction of the position
sensor. The filter wheel must also be securely tightened,
so that no slippage or vibration can occur. See Figure 5-1.
NOTE: Refer to Figure 5-1 when installing filter screens. Screens should be
installed in the filter disk cup, under the filter holder. Also, if a bal-
ance ring is used, it should be placed over the screen.
c. After screening to bring the measuring voltage to within
10% of the reference voltage, adjust R3 as in step a above
to make the measuring peak voltage read the same as the
reference peak voltage.
5. Turn the NORM/ZERO switch to ZERO. The analysis section
meter should be made to read zero by adjusting the coarse ZERO
control on the analysis section power module.
6. Check the control module SPAN setting to make sure it agrees
with the calibration results obtained by TAI (see Specific
Application Data in the Appendix).
7. Adjust the ZERO control on the control module to give a zero
reading on the control module meter.
8. Add span fluid (see Span Fluid, above) to the sample cell. Make
certain that all of the zero fluid is displaced.
9. Adjust the control module SPAN control to obtain the correct
meter reading with reference to the concentration of span fluid.
For example, if the sample contains 100% of whatever the