Lines of variables "Max. zero calibration deviation" / "Max. span calibration deviation":

The deviation between two zero or span gas concentrations will be determined during the stability time of the calibration procedure (see menu "Calibration Procedure Setup"

p.5-9/10). The maximum calibration deviation is the deviation tolerance expressed as percentage of the current end of range value. The calibration procedure will only be possible within this range.

If you choose a very small deviation tolerance, perhaps the calculated deviation is out of range during the whole calibration procedure and the calibration will run into time out. If you choose a very large deviation tolerance, the calibration will also be done in ranges with a little stability.

Value is usually: 10% or 20%

Line of variables "Check deviation":

♦Enabled: The stability and tolerance control during the calibration procedure will be based on the values of the menu "Tolerances".

♦Disabled: The calibration procedure is running without stability and tolerance control. Any Calibration will be accepted.

Example:

 

♦ End of range:

1000 ppm

♦ Max. calibration deviation:

20% (equivalent 200 ppm)

♦ Desired value:

990 ppm

♦ Display:

720 ppm

♦ Deviation:

250 ppm (more than 200 ppm!)

♦ Result:

Max. calibration procedure time over limit;

 

Calibration will be canceled !

Potential solutions:

♦Adjust 100% in the line "Max. zero calibration deviation" resp. "Max. span calibration deviation"

or

select "Disabled" in the line "Check deviation".

♦Result: Any Calibration will be accepted!

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NGA 2000

90003482(2) [NGA-e (MLT-Software 3.2.X)] 07/98