Emerson Rosemount CCO 5500, Reference Manual

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2. Span Adjust
3. Calibrate
Set detectors
You can display both the D1 and D2 levels; you can also display saturation counts. To give
an immediate response to any alterations that are required, the filters and gas cells are not
moved during this operation.
Refer to Section 3.5 for a discussion of the detector level and saturation count.
Span adjust
Note
Rosemount
™
initially sets the span factor at the factory; do not adjust it unless the instrument
sensitivity is suspected. In any case, Rosemount recommends that you record the orginal value
before making adjustments.
You can adjust instrument sensitivity if a known concentration of gas exists between the
source and receiver units and instrument sensitivity is supsected. If a problem arises,
consult Rosemount.
You may need to adjust the span factor if you have fitted new gas cells or filters.
Calibrate
Re-enter the Mode 5 CALIBRATE menu and proceed to the Calibrate option.
You can calculate the basic calibration of the instrument from this routine. It is preferable
to conduct this operation with the plant shut down to ensure a zero gas concentration
within the duct. If this is not possible, the instrument can calibrate to a known value of the
gas concentration - the calibration target.
Configuration and startup
Reference Manual 47