"NEED CALIBRATION" - May be displayed if the internal diagnostics detect a calibration problem. Below are listed the assorted causes:
"DUE TO MEMORY CLEAR " - When memory is cleared a full calibration is necessary.
"DUE TO TEMPERATURE READ WHITE " - If a 10 degree C. change occurs, the instrument requires a new white calibration.
"DUE TO 12 HOUR FLAG READ WHITE " - Calibration is recommended every 4 hours. If 12 hours pass without a cal the instrument will flag the operator to cal white.
"DUE TO BAD ZERO CAL READ ZERO " - Zero reflectance calibration measurement was not properly updated.
"DUE TO ABORTED CAL READ WHITE " - If the user began a calibration and exited before completion.