Systems and methods for detecting a liquid level
AssigneeElbit Systems of America / Kmc Systems, Inc.
InventorFrank Pawlowski
Life of this patent
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Abstract
A method for detecting a liquid surface of a liquid sample with a pipetting tip, the method includes receiving an indication of a capacitance of the pipetting tip, and determining, based on a rate of change of the indication of the capacitance rising above a first preselected threshold, that the pipetting tip has come into contact with the liquid surface. The method also includes determining, based on the rate of change of the indication of the capacitance falling below a second preselected threshold, that the pipetting tip has lost contact with the liquid surface.
Claims17
A method for detecting a liquid surface of a liquid sample with a pipetting tip, the method comprising:
- receiving an indication of a capacitance of the pipetting tip;
- determining, based on a rate of change of the indication of the capacitance rising above a first preselected threshold, that the pipetting tip has come into contact with the liquid surface;
- and
- determining, based on the rate of change of the indication of the capacitance falling below a second preselected threshold, that the pipetting tip has lost contact with the liquid surface.
A system comprising:
- a pipette probe;
- a capacitance to pulsewidth generator coupled to the pipette probe, the capacitance to pulsewidth generator configured to output a pulse having a width based on a capacitance seen by the pipette probe;
- and
- a signal processor coupled to the capacitance to pulse width generator, the signal processor, the signal processor configured to compare a signal based on the width of the pulse with a preselected positive threshold and a preselected negative threshold.
A system comprising:
- a pressure transducer in fluid communication with an interior volume of a pipette tip;
- a signal processor coupled to the pressure transducer, wherein the signal processor is configured to output a signal having an magnitude based on a rate of change of a pressure in the interior volume of the pipette tip.
A method comprising:
- initiating a level sensing operation;
- measuring, during the level sensing operation, a first noise level in an output of a discriminator;
- setting a positive threshold based on the first measured noise level in the output of the discriminator;
- during the level sensing operation, withdrawing a pipetting tip;
- measuring a second noise level, during the withdrawing, of the output of the discriminator;
- and
- setting a negative threshold based on the second measured noise level.
Dependencies are inferred from the claim text.