Teledyne 9110AH - Nitrogen oxides analyzer - Manual (Page 99)

TELEDYNE Model 9110AH NO
X
Analyzer Operator Manual, 01620, Rev. F
7-11
The offset value gives information about the background signal level. Check the observed
offset value against the factory value in Table 2-1. If significantly higher, check Section 9.1.6.
Increasing readings are a predictor of problems.
Table 7-9: Calibration Quality Check
Step Number Action Comment
1. Scroll the TEST
function menu
until the NO
x
SLOPE is
displayed.
The SLOPE value for NO
x
should be 1.0 0.3. If the value is
not in this range, check Section 9.1.6. If the SLOPE value is in
the acceptable range the instrument will perform optimally.
2. Scroll the TEST
function menu
until the NO
x
OFFSET is
displayed.
This number should be near zero. A value of 0.0 50 indicates
calibration in the optimal range. This number already has the
AutoZero value subtracted out and is mainly the background
signal due to the molybdenum converter. If the OFFSET value
is outside this range, check Section 9.1.6.
3. Scroll the TEST
function menu
until the NO
SLOPE is
displayed. The SLOPE value for NO should be 1.0 0.3. If the SLOPE
is in the acceptable range the instrument will perform
optimally. If the value is not in this range, check Section 9.1.6.
NOTE:
The NO and NO
x
slopes should be equal within 0.1.
4. Scroll the TEST
function menu
until the NO
OFFSET is
displayed. The instrument will now display the NO OFFSET value. It
should also have a value near zero (0.0 50). This number
already has the AutoZero reading subtracted out and should be
near zero. If the OFFSET value is outside this range, check
Section 9.1.6.
7.10 Converter Efficiency Compensation
The converter efficiency factor compensates NO
2
readings for converter efficiency. The NO
2
component of the NO
x
reading is also compensated when instrument is in switching mode. An
efficiency factor of 1.0 disables efficiency compensation, acceptable values are .80 to 1.20.
There are some fault conditions that can be revealed by a NO
2
channel linearity check, such as a
faulty switching valve or a partially plugged converter. For the converter to operate properly
there should be at least a few percent oxygen present in the sample stream.
There are 2 ways to enter the NO
2
converter efficiency.
Method 1. is covered in Table 7-10.