Patent ID: 9517468
Filing Date: 2016-12-13
CPC Classification: B01L,G01N

Claim Text:
1. A method of calibrating a position of a nozzle tip relative to a sample container, comprising: providing a nozzle including a nozzle tip, the nozzle operably configured to aspirate a sample fluid from the sample container; providing a sample rack having a receptacle configured to contain the sample container during the aspirate the sample rack having a registration location; inserting a calibration target in the receptacle of the sample rack; positioning the nozzle over the calibration target at a home height location (HM); moving the nozzle downward from the home height location (HM) a distance (D) until a portion of the calibration target is sensed; positioning the nozzle over the sample rack; moving the nozzle downward until a portion of the registration location of the sample rack is sensed to determine a distance (R) from the home height location (HM) to the registration location; imaging the assembly of the sample rack and the calibration target to determine a height (H) between the registration location and a top of the calibration target in pixel space; and calculating a translation ratio (TR) between the height (H) measured in the pixel space and the height (M) measured in machine space, wherein (M) is related to distance (R) and height (H); wherein each of distance (D) and distance (R) is measured in a number of steps (S) of a stepper motor; the method further comprising: generating the translation ratio (TR) between the number of steps (S) and the height (H); and using the translation ratio (TR) to drive the nozzle tip to a predetermined drive depth (DD) in a sample container.