Teledyne 514 Instruction Manual page 37

control temperature. Make certain that bubbles are not introduced
or formed in the cell. (Some back-pressure may help avoid this.)
Gas samples can be introduced at about 200 ml/minute.
2. Turn the power module NORM/ZERO switch to NORM.
3. Turn the power module MEAS/REF switch to REF. Verify that
the analysis section meter reads 9±0.1 volts.
4. Make adjustment of the measuring peak voltage as follows
(zero fluid must be in the sample cell during this adjustment):
a. Switch the MEAS/REF switch to the MEAS position.
The meter should read almost the same as in the REF
mode. If the reading is somewhat different, the
measuring peak may be re-adjusted with R3 on the peak
level detector circuit card (see dwg. B-14554 and "Peak
Level Detector" in Chapter 5) inside the detector
module.
b. If the measuring peak is so far out of balance with the
reference peak that it can no longer be adjusted with
potentiometer R3, the optical filters require re-
screening. If the analyzer has been in use for some time,
it is possible that the sample cell windows need cleaning
or that a filter has deteriorated.
Another cause of peak imbalance might be that the
sample 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
Teledyne Analytical Instruments
A Business Unit of Teledyne Electronic Technologies
Operations 4.0
4–7