Dispense task parameters About this topic The Dispense task dispenses liquid into a microplate or reservoir. This topic describes the task parameters. To run the Dispense task, see Performing a task using Bravo Diagnostics. Parameter descriptions The Dispense task has the following parameters. Parameter Description Empty tips The option to empty all liquid from the tips instead of using the dispense volume specification. Volume (µL) The volume of liquid to be dispensed from each pipette tip. Blowout volume (µL) Specifies the volume of air to dispense after the main volume has been dispensed while the tips are still in the wells. Typically, the blowout volume is the same as the pre-aspirate volume. Note: Blowout only occurs in the last quadrant dispensed for a given Dispense task. Liquid class The pipetting speed and accuracy. IMPORTANT To ensure consistent pipetting, always select a liquid class for liquid-handling tasks. Distance from well bottom(0–100 mm) The distance between the end of the pipette tips and the well bottoms during the Dispense task. If you specify dynamic tip retraction, this is the starting distance. IMPORTANT The labware definition must be accurate and the teachpoint must be precise in order for the system to position the tips at the correct distance from the well bottom. Dynamic tip retraction(0–20 mm/µL) The rate at which to raise the pipette head during the Dispense task. Use dynamic tip retraction to prevent spills as the pipette tips displace the liquid. To move the tips: • At the same rate as the volume change. Calculate dynamic tip retraction (DTR) as follows: DTR = (well depth)/(well vol) = 1/A, where A is the cross-sectional area of a well with straight walls • Faster than the volume change. DTR > 1/A • Slower than the volume change. DTR < 1/A The starting and ending positions can be calculated as follows: (Vdispensed * DTR) + Distancewell bottom Pipette technique The pipette location offset you want to use for the Dispense task. The list of pipette techniques are defined in the Pipette Technique Editor. Perform tip touch The option to touch the pipette tip on one or more sides of the well. Which sides to use for tip touch The side or sides of the well to use during tip touch: North, South, East, West, North/South, West/East, West/East/South/North. Tip touch retract distance(–20 to 50 mm) The vertical distance for the pipette tips to rise before touching the sides of the wells. Tip touch horizontal offset(–5 to 5 mm) The horizontal distance the tips move. The value is based on the well diameter specified by the labware definition. For example, if you set a value of: • 0, the tips move a horizontal distance equal to the well radius • > 0, the tips attempt to move past the well radius, which results in a more forceful tip touch • < 0, the tips move a distance less than the radius of the well, resulting in a lighter tip touch Related information For information about… See… Opening Diagnostics Opening Bravo Diagnostics Editing the labware classes, liquid library, or pipetting techniques VWorks Automation Control Setup Guide Performing a diagnostic task Performing a task using Bravo Diagnostics Reporting a problem Reporting problems
