2-Point Calibration; Figure 28 2-Point Calibration Page - Michell Instruments XTP501 User Manual

XTP501 & XTC501 User's Manual
3.2

2-Point Calibration

This is a 2-point adjustment that is overlaid on top of the factory calibration. It is
designed to correct minor drift and minor changes during transit. This calibration makes
the unit more accurate throughout the range than the single point calibration.
1. Apply the lower calibration gas and purge the unit for at least 5 minutes.
View the chart until a flat line shows for 1–2 minutes.
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2. Press ENTER to highlight CAL TYPE and set to 2 POINTS. Press ENTER
to de-select.
3. Press ENTER to highlight REF GAS 1 and use the Up () and Down ()
buttons to match the value of the concentration of the lower calibration
gas. NOTE: This value only needs to be set when using a new
gas cylinder. Press ENTER to de-select.
4. Ensure the Adjusted value at the bottom of the page has stabilized.
NOTE: There will be a ~ symbol next to 'Adjusted' while the
reading is stabilizing. When the ~ symbol disappears, the
reading will be stable and the next change can be made.
5. Press ENTER to highlight ACTUAL 1 value and press the Up () button
3 times. Ensure that the Adjusted value equals the REF Gas 1 value
(±0.01%). Press ENTER to de-select.
6. Apply the upper calibration gas and purge the unit for at least 5 minutes.
View the chart until a flat line shows for 1–2 minutes (see above).
7. Press ENTER to highlight REF GAS 2 and use the Up () and Down ()
buttons to match the value of the concentration of the upper calibration
gas. NOTE: This value only needs to be set when using a new
gas cylinder. Press ENTER to de-select.
8. Ensure that the Adjusted value at the bottom of the page has stabilized.
9. Press ENTER to highlight ACTUAL 2 value and press the Up () button
3 times. Ensure that the Adjusted value now equals REF Gas 2 value
(±0.01%). Press ENTER to de-select. Press ESC to return to the Main
Menu.
10. The Adjusted reading will now be the same as that displayed on the
Main Page and be equal to the upper calibration gas.
11. The calibration process is complete. Return to sampling the process gas.
Michell Instruments
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Figure 28 2-Point Calibration Page
CALIBRATION
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