Model 202 Ozone Monitor Manual Rev. J-4
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5. For each ozone concentration standard, record the response of the ozone
monitor as well as either the response of the UV photometer or the transfer
standard.
6.6.4. Calibration Curve
1. Plot the Model 202 Monitor responses (y-axis) versus the corresponding
standard ozone concentrations (x-axis).
2. Fit the data to a straight line (y = mx + b) using the linear regression
technique to determine the calibration relationships, where m = slope and b
= intercept.
3. Determine if any points deviate significantly from the line, which is an
indication of an error in determining the calibration curve. The error may
be due to the calibration setup or the ozone monitor being calibrated. The
most likely problems in the ozone monitor are leaks, a malfunctioning
ozone scrubber, a contaminated valve, or contamination in the optical
setup. See the “Troubleshooting” section of the manual (Section 8).
4. The inverse of the slope of the line (1/m) is the gain factor (S) and the
negative of the intercept (-b) is the offset (Z) that need to be applied to the
ozone monitor response to calibrate it to the primary ozone standard. If the
intercept is outside of the range from -10 to 10 or the slope is outside of the
range from 0.90 to 1.10, this is an indication of a problem in the calibration
setup or the ozone monitor being calibrated. The most likely problems in
the ozone monitor are leaks, a malfunctioning ozone scrubber, a
contaminated valve, or contamination in the optical setup. See the
“Troubleshooting” section of this manual.
5. Enter the calibration menu (
Main Menu / Cfg / Cal / O3
) in the instrument
software and set the calibration parameters Z and S as determined above
(see Section 3.14 of this manual).
Refer also to our Technical Note No. 015 on calibration of 2B Tech Ozone Monitors,
posted on our website:
https://twobtech.com/docs/tech_notes/TN015.pdf
.
