5.3 Manual Background
A background is a measurement that is made when CO free air is drawn through the reaction cell. The
resulting measurement signal (background) will include signals unrelated to CO. The background is an
electronic baseline, it is normally run every 24 hours automatically. There is sometimes a need for the
user to run a manual background.
Note: A manual background is recommended before commencing a multipoint precision check.
Equipment Required
• N/A
Procedure
1. Open - Main Menu → Calibration Menu.
2. Start - Manual Background → Running.
3. Manual background will now display running and will proceed to draw air from the CO-CO
2
converter for 4 minutes (3 minutes of fill time and 1 minute of measure). The user can press stop
at any time to cancel the background. At the end of the 4 minute period a new background voltage
will be recorded in the event log as well as in the Calculation Factors Menu.
5.4 Zero Calibration
Zero calibrations are used to determine the zero response of the instrument and apply an offset to the
reading.
Performing a zero calibration will adjust the Zero Offset CO. This offset can be checked in the Main
Menu → Service Menu → Calculation Factors Menu and should be very close to zero. A large offset
may indicate a problem with the instrument (refer to Section 7).
Note: Ecotech encourages regular zero precision checks; however Ecotech recommends that the
zero calibration only be performed when specifically required as it may mask issues that should be
addressed during maintenance/service.
A zero calibration can be performed either through the Calibration Port, Background Air Port or the
Sample Port. Refer to the instructions outlined in the next three sections:
Note: Ensure the instrument has been running for at least one hour before any calibration is
performed to ensure sufficient stability.
5.4.1 Calibration Port
Equipment Required
• Zero Air Source (refer to Section for 1.3 definition)
To Next Page
Loading...
