Can I adjust greater than 2% TOC and still be within 643/645 compliance?
PAT700/643 and 645 Regulation
The 645 regulation states that the cell constant cannot change by more than 2% during installation. The gain and offset of the analyser are the cell constants. The user slope is what will be changed during a conductivity or TOC calibration; therefore the units will always stay within the 645 compliance even when adjusting greater than 2%. The 5% and 10% limits are user definable and are generally for ensuring that the standards used are still in good condition.