Methods and systems for calibration of a positional orientation between a sample container and nozzle tip

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);
• the method further comprising, after calibration, imaging a sample container to determine an imaged height of the sample container, and
• multiplying the imaged height (IH) by the translation ratio (TR) and a factor to obtain a drive distance to drive the nozzle tip in machine space.

A method of calibrating a position of a nozzle relative to a sample container, comprising:

• providing a moveable nozzle having a nozzle tip, the moveable nozzle operably configured to aspirate a specimen;
• providing a sample rack having a receptacle and a registration location comprising a planar surface feature;
• providing a sample container inserted in the receptacle of the sample rack having a small sample cup (SSC) inserted in the sample container;
• positioning the nozzle over the SSC at a home position (HM);
• moving the nozzle downward from the home position (HM) until the nozzle tip contacts a register location comprising a bottom surface of the SSC;
• determining a distance (D) between the home position (HM) and the bottom surface of the SSC;
• imaging the planar surface feature of the sample rack and the top surface of the SSC;
• determining a height (H) from the planar surface feature to a top of the SSC, the height (H) determined in pixel space;
• and calculating a translation ratio (TR) between the height (H) measured in pixel space and a height (M) measured in machine space, wherein the height (M) is related to the distance (D)
• wherein the distance (D) 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.