Dispense to Waste task parameters

About this topic

This topic describes the task parameters for the Dispense to Waste task, which is available only for a location with a Tip Wash Station (also known as a MicroWash Reservoir).

The Dispense to Waste task moves the pipettes by a horizontal offset and then dispenses used fluid in between the chimneys in the Tip Wash Station. The software calculates the horizontal offset automatically based on the labware definition for the Tip Wash Station.

To run the Dispense to Waste task from Diagnostics, see Performing a task using Bravo Diagnostics. To use the task in a protocol, see the VWorks Automation Control User Guide.

Parameter descriptions

The Dispense to Waste task has the following parameters.

 

 

 

Parameter	Description
Empty tips	The option to empty all the liquid from the head into the Tip Wash Station outside the chimneys.
Volume (µL)	The volume of liquid to be dispensed from each pipette.
Blowout volume (µL)	Specifies the volume of air to dispense after the main volume has been dispensed while the tips are still in the Tip Wash Station.
Liquid class	The pipetting speed and accuracy. IMPORTANT To ensure consistent pipetting, always select a liquid class for liquid-handling tasks.
Override dispense flow rate from liquid class	The option to override the dispense velocity specified in the liquid class. Selecting this option enables you to specify a value for the dispense flow rate without changing the liquid class.
Dispense flow rate (0–500 µL/s)	The numerical value or the JavaScript variable that will override the dispense velocity setting in the liquid class. A JavaScript variable enables the value to be assigned later, for example through a VWorks form. Using a VWorks form, an operator could easily change the flow rate for a dispense step in increments from as low as 1 µL/min up to 1001 µL/min using the same liquid class. If the task is included in a VWorks macro, a JavaScript variable enables you to change the value for the task at the macro level. IMPORTANT The software requires that the flow rate value be in microliters per second (µL/s) at run time. If you want an operator to enter the value in microliters per minute (µL/min), you can use scripting to convert the values for the software to use.
Distance from well bottom (mm)	The absolute distance between the end of the pipette tips and the bottom of the Tip Wash Station during the Dispense to Waste 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 (mm/µL)	The rate at which to raise the pipette head during the Dispense to Waste task. Use dynamic tip retraction to prevent spills as the pipette tips displace the liquid. To move the pipettes: • 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
Perform tip touch on North/East side	The option to touch the tip on an outer side of the adjacent northeast chimney or wall in the Tip Wash Station after performing the dispense.
Tip touch retract distance (–20 to 50 mm)	The vertical distance for the pipette tips to rise before performing the tip touch.
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