Performing a Span Calibration

A Span calibration is performed the similarly to the zero calibration but with two small changes.  First, the selector button at the top should be on Span Calibration instead of Zero Calibration. 

Second, the gas values for the specific cylinder of gas being used need to be entered into the Target values.  To do this, press the blue box associated with each gas and enter the value shown on the cylinder.  For example, the nominal value for CO may be 20%, but your cylinder may actually have 19.96% CO.  19.96 is the value that should be entered as a Target.

 

After the gas values have been entered, proceed with the calibration in the same manner as with the zero calibration.  Never perform a span calibration without first doing a zero calibration.