Method For Span Calibration By Check Gas - Fuji Electric ZPA Service Manual

(2) Method for span calibration by check gas

The method for span calibration by use of check gas (give in 2) is explained based on the example.
(Since span calibration has an error of calibration curve, preset a calibration indication on the calibration curve
graph attached to this analyzer for indirect calibration.)
The following calibration curve graph is attached to the test results for the product. In graph, the calibration
1)
curve by the scale gas (that is similar to plant gas and determines scales of this analyzer) and the calibration
curve by the check gas that is adjusted by the scale gas (gas of simple composition of N
facilitate the analyzer check) are drawn.
Y
1.0V
0.9
0.89V
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0 0.1
Calibration curve graph attached to the product
When using 0.95% CO
2)
In graph, a point of 0.95% on X-axis should be stretched to upward, draw a line toward Y-axis from the
cross point with the check gas calibration curve. From the cross point with calibration curve on the scale gas
composition, 0.89% or equivalent values can be obtained.
Set this point (0.89%) to the span calibration concentration of the calibration concentration set value.
3)
Supply 0.95% check gas to perform span calibration. Then, the concentration value is corrected to 0.89%.
4)
Measurement suited to actual plants can be performed by this error correction of calibration curve.
30
0.2 0.3 0.4 0.5
Measuring gas concentration
and remainder N
2 2
0.6 0.7 0.8 0.9
0.89%CO
0.95%CO
2
(check gas) as calibration gas,
balance gas to
2
Calibration curve by
scale gas
(composition of plant
gases)
Calibration curve by
check gas
(N balance gas)
2
* When supplying
check gases to
analyzer adjusted by
the scale gas
composition.
X
1%CO
2
2
TN5A1191-E