Teledyne 200AU - page 116

Teledyne API Model 200AU NOX Analyzer Instruction Manual, 02293, Rev. F
7-34
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. Also,
after calibration check the PREREACT – TEST function reading and compare it against the
factory checkout value. Increasing readings are a predictor of problems.
Table 7-18: Calibration Quality Check
Step Number Action Comment
1. Scroll the TEST
function menu until
the NOx SLOPE is
displayed.
The SLOPE value for NOx 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 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 NOx slopes should be equal within ± 0.1.
3. Scroll the TEST
function menu until
the NOx OFFSET is
displayed.
This number should be near zero. Values between –10 to 150
mV are acceptable. This number already has the PREREACT
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.
4. Scroll the TEST
function menu until
the NO OFFSET is
displayed.
The instrument will now display the NO OFFSET value. Values
between –10 to 150 mV are acceptable. This number already
has the PREREACT reading subtracted out and should be near
zero. If the OFFSET value is outside this range, check
Section 9.1.6.
After the above procedure is complete, the M200AU is ready to measure sample gas.