Honeywell 301C Manuel De L'utilisateur page 61

7. To calibrate the device, scroll to Set Span** and change the span
gas calibration value using this procedure;
a. Using the right arrow, move the cursor to xxx PPM (span
value field). Press Enter to select the field (it is editable
when flashing).
b. Use the up or down arrows to increase or decrease the
value, press Enter to validate the new value.
c. Move the cursor back to Set Span and press Enter to start
the calibration.
The device Span is being calibrated. The screen will display the
device's status as "In calib..." until the calibration is complete.
**When selecting Set Span, make sure that the device has been
supplied with the appropriate calibration gas before and during the
calibration process.
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