Rack Wizard

The Rack Wizard guides you through the process of creating a new rack for the Gemini Configuration. To start the Wizard, choose Configuration in the Setup menu, click the Racks tab and click New. Then enter a name of your choice for the new rack and click OK.

Rack Wizard, step 1 of 5

This step specifies basic settings for the rack.

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The following list illustrates the two rack types supported by Gemini:

Figure 5-10: Rack Wizard, step 1 of 5

Type Name Comment

Rectangular rack This is a rack where the wells are arranged in rows and columns, e.g. a microplate. The first well is rear left; the last well is right front.

Table 5-13: Rack types

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See page 51 for a list of the supported options.

When defining a DITI rack, you also have to specify DITI Capacity and DITI Offset. You can define up to four DITI types. When Gemini is first installed, DITI Type 1 is the 200 µl DITI, Type 2 is the 1000 µl DITI and Type 3 is the 10 µl Low Volume DITI. Type 4 can be used for custom DITI sizes and lengths.

When defining a Te-MagS (Tecan magnetic bead separator device), you also have to specify Plate Type and Z-offset. The plate type ensures that the Te-MagS moves to the correct positions when performing an operation. When the Te-MagS moves to the incubation position, it slightly lifts the plate. This distance is specified in the Z-Offset field as a negative value.

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You can choose a unique color here to make it easier for you to identify this rack type in the Worktable window. The default rack colors are as follows:

• Microplate racks: blue

• Tube racks: green

• DiTi racks: red

• Washstation racks: yellow Default for all other rack types: blue.

Rectangular rack with offset

This rack is similar to the rectangular type, but every second column is displaced in the +Y direction. The spacing of the wells in the Y direction are the same for all columns. In addition to the X and Y positions of the first and the last well, you must also specify the first well of the second column with “Y2 (column 2)”.

Table 5-13: Rack types

Rack Wizard, step 2 of 5

This step specifies well parameters for the rack.

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Specify the total number of wells in the X-direction (max. 128).

Rows

Specify the total number of wells in the Y-direction (max. 128).

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Select the shape of the bottom of the well.

Height of v

For a well with a v-shaped bottom, specify the vertical distance in mm from the lowest point of the v (Z-max) to the beginning of the cylindrical part of the well.

Figure 5-11: Rack Wizard, step 2 of 5

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Specify the area of each well in mm². Click Calculate area to display a dialog box which helps you to calculate the area from the diameter or from the length and the width.

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Specify the number of tips which can access the well at the same time. Specify “1” for normal wells. Specify the appropriate number for troughs (e.g. “8” for a Trough 100ml).

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This parameter is used when you activate tip touching for the liquid class in the pipetting script. When tip touching is activated, Gemini dispenses to the destination container in the normal way, but then moves the tips to the side of the well and back before

retracting them. This helps to remove any drops which may be adhering to the tip.

Gemini also uses this parameter if you select an offset (non-center) x-position for aspiration. This is done on the Aspiration tab of the liquid class and is mainly used for the Te-MagS.

Note:

Troughs are normally specified with length and width. To do this, click Calculate area and press the Delete key to delete the diameter value. The length and width fields will then become active.

Rack Wizard, step 3 of 5

This step specifies the rack coordinates. It also opens the Move dialog box (not visible in the Figure) to help you with positioning.

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Teaching is the process of showing Gemini the required positions on the worktable by physically moving the LiHa (see the table: “Moving the LiHa using the numeric keypad”

on page 38) and then clicking the appropriate buttons in the dialog boxes.

Specify the carrier, grid and site that you want to use to define the rack:

Choose the carrier from the list, specify the grid position and the site. An easy way to choose the correct carrier, grid, site and rack is to click on the object in the Worktable window (this does not apply to RoMa only carriers, which are hidden).

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Move the LiHa above the first well of the rack (at the rear left of the rack) and click the corresponding Get button. This copies the current LiHa X and Y coordinates to the position fields in the dialog box.

Move the LiHa above the last well of the rack (at the front right of the rack) and click the corresponding Get button. This copies the current LiHa X and Y coordinates to the position fields in the dialog box.

See “Rack coordinates” on page 48 for more information on this topic.

Figure 5-12: Rack Wizard, step 3 of 5

For racks with offsets, you also need to move the LiHa above the first well of the second column and click the Get button next to the field “Y2 (column 2)". See Table 5-12 on page 51.

Tip: If you click the Move To buttons, this moves the LiHa to the X and Y coordinates shown in the dialog box.

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Check that the Y-distance (the spacing between adjacent wells) which is shown graphically by the vertical bar lies within the green area (see “Y-distance of wells” on page 52). If the vertical bar lies within the red area, you may have specified the coordinates incorrectly or inaccurately.

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Move the LiHa to the Z-Travel position above the first well of the rack and click the corresponding Get button. This copies the current LiHa Z coordinate to the Z-Travel field in the dialog box.

Repeat this process for the Z-Dispense, Z-Start and Z-Max positions.

See “Rack coordinates” on page 48 for more information on this topic.

Tip: If you click the Move To buttons, this moves the LiHa to the Z coordinates shown in the dialog box.

Rack Wizard, step 4 of 5

This step specifies the carrier and site assignments for the rack.

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For each of the carriers which will be used with the new rack, check the checkboxes alongside the allowed sites.

Figure 5-13: Rack Wizard, step 4 of 5

Rack Wizard, step 5 of 5

This step specifies settings for septum piercing and precise positioning.

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If you activate this option, Gemini executes special piercing movements when accessing the rack. It will pierce from Travel to Start and then retract from Z-Start to Z-Travel. Liquid level detection is not available with this option activated.

Pierce with

Specify the piercing speed in mm/s.

Retract with

Specify the retract speed after piercing in mm/s.

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If you activate this option, Gemini executes a special movement to increase positioning accuracy, e.g. for 1536 well plates. When accessing a rack for the first time in a sequence of pipetting commands, it makes a normal move to X-Start/Y-Start. It then makes a high resolution move to the actual pipetting position. This sequence of movements eliminates mechanical backlash and ensures the highest possible accuracy. X-Start should be set to ca. 0.4 cm to the left of the first well in the Figure 5-14: Rack Wizard, step 5 of 5

rack. Y-Start should be set to ca. 0.4 cm behind the first well in the rack. Note: The first well is at the rear left of the rack.

X-Start

Teach the required X-Start position for the precise X movement: Move the LiHa above the X-Start position and click the corresponding Get button. This copies the current LiHa X coordinate to the X-Start field.

Y-Start

Teach the required Y-Start position for the precise Y movement: Move the LiHa above the Y-Start position and click the corresponding Get button. This copies the current LiHa Y coordinate to the Y-Start field.

Move with

Specify the speed for the precise positioning movement in mm/s.

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When you are finished, click Finish to store the new rack in the Gemini Configuration.