Wash Tips task parameters

About this topic

The Wash Tips task washes pipette tips using a number of aspirate and dispense actions. This topic describes the task parameters.

To run the Wash Tips task, see Performing a task using Bravo Diagnostics.

Parameter descriptions

The Wash Tips task has the following parameters.

 

 

 

Parameter	Description
Empty tips	The option to empty the entire contents of the pipette tips, including fluid and air. The Volume parameter is ignored if this option is selected.
Volume (µL)	The volume of liquid to be dispensed from each pipette tip.
Pre-aspirate volume (µL)	The volume of air to be drawn before the pipette tips enter the liquid.
Blowout volume (µL)	Specifies the volume of air to dispense after the main volume has been dispensed. 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 action.
Liquid class	The liquid class associated with this liquid. IMPORTANT To ensure consistent pipetting, always select a liquid class for liquid-handling tasks.
Mix cycles	The number of times you want to aspirate and dispense. Each cycle consists of one aspirate action and one dispense action.
Distance from well bottom (mm)	The distance between the end of the pipette tips and the well bottoms during the Wash Tips task. 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 extension (mm/(µL)	The rate at which the pipette head moves during the Wash Tips task. The software calculates the distance over which the tips will move without crashing. Use dynamic tip extension 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 extension (DTE) as follows: DTE = (well depth)/(well vol) = 1/A, where A is the cross-sectional area of a well with straight walls • Faster than the volume change. DTE > 1/A • Slower than the volume change. DTE < 1/A The starting and ending positions can be calculated as follows: (Vdispensed * DTE) + Dwell bottom (Vaspirated * DTE) + Dwell bottom
Perform tip touch	The option to touch the pipette tip on one or more sides of the well.
Which side to perform tip touch	The wall or walls for tip touch: North, South, East, West, North/South, West/East, West/East/South/North. If you also select the Dispense to waste during wash option, the tip touch is performed on the northeast side only.
Tip touch retract distance	The vertical distance the pipette tips rise before touching the sides of the wells.
Tip touch horizontal offset	The horizontal distance the tips move. The value is based on the well diameter specified by the labware definition. The value of the parameter determines the direction of movement: • 0. Tips move a horizontal distance equal to the well radius. • Great than 0. Tips attempt to move past the well radius, which results in a more forceful tip touch. • Less than 0. Tips move a distance less than the radius of the well, resulting in a lighter tip touch.
Pump fill speed (%)	The speed, in percent of maximum speed, of liquid flow into the reservoir. For the MicroWash Reservoir, this value should be high enough for the washing liquid to just bubble over the tops of the chimneys.
Pump empty speed (%)	The speed, in percent of maximum speed, of liquid flow out of the the reservoir. For the MicroWash Reservoir, this value should be slightly higher than that of the inflow pump to prevent an overflow.
Dispense to waste during wash	The option to move the tips by a specified offset (defined in the Labware Editor) and dispense used fluid outside of the reservoir chimney. This option applies only to reservoirs that have chimneys.
Dispense to waste at height (mm)	The height at which the dispense action occurs. For example, during the dispense action, the tips move up to clear the chimneys, move the offset distance, and then lower to the distance you specified. If you want the lower the tips by 10 mm, specify –10 mm.

 

 

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