1-Point Calibration; Figure 27 1-Point Calibration Page - Michell Instruments XTP501 User Manual

CALIBRATION
3.1

1-point Calibration

This is a single point offset overlaid on top of the factory calibration. It is designed to
correct minor drift and minor changes during transit. This calibration makes the unit
very accurate at the calibration point and improves accuracy throughout the range.
The calibration gas should be of a value that is within the main area of interest, i.e.
if main points of interest for a 0-25% range instrument are around the 6% area then
apply a calibration gas as close as possible, in the example below we used 6.5% O
1. Apply the 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 open the Passcode Page – 1919 Passcode. Navigate to
the Field Cal page using the Up () button. Press ENTER to highlight
CAL TYPE and set to 1 POINT. 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 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. Press ESC to return to the Main
Menu.
6. The Adjusted reading will now be the same as that displayed on the
Main Page and be equal to the calibration gas.
7. The calibration process is complete. Return to sampling the process
gas.
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XTP501 & XTC501 User's Manual
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Figure 27 1-Point Calibration Page
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99976 Issue 1.1, May 2020
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