SECTION 6
CALIBRATION
Subjects covered in Section 6:
* 6.1 Positioning the Instrument on the White Standard
* 6.2 Calibration Procedure
The 978 should be calibrated to the X-Rite standard the first thing each
day and every four hours of operation thereafter. However, a "NEED
CALIBRATION" message will appear in the display if:
* The calibration procedure has not been performed for 24 hours.
* There is a 10°C change in temperature since the last calibration.
* Zero reflectance is measured improperly.
* The lamp output changes.
Whenever this message appears the calibration procedure should be
performed before another measurement is taken to ensure accuracy.
Calibration Notes
- Dirt or dust in the optics area will cause an inaccurate calibration
reading. Refer to Section 8.2 for the optics cleaning procedure.
- The ceramic Reflection Standard is dramatically affected by smudge
marks, dust, and finger prints. The standard should be cleaned using a
mild soap and warm water solution, thoroughly rinsed with warm
water, and wiped dry with a lint free cloth. You must let the standard
dry completely before taking a calibration reading.
- If you are having linearity problems it’s possible that there is dust in
the optics or Zero Reflectance has drifted. If you improperly measure
Zero Reflectance the unit can not automatically detect the drift. If you
suspect this is the case, you should manually activate Read Zero
Reflectance. Refer to Read Zero Reflectance in Section 6.2.
- Do not move the 978 while taking a calibration measurement. If
motion is detected an error message will be displayed and calibration
aborted.
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