The following sections are covered in this article:

  1. Working area diagrams

  2. Math for maximum labware heights based on pipette

  3. How to use the X/Y/Z coordinates in a Python protocol

Working area diagrams

Click below for downloadable .pdfs of drawings that lay out the working area of the OT-2 as well as the max height distance a piece of labware can be depending on the pipette.

Math for maximum labware heights based on pipette

  • P1000, single-channel: 223.46 - 78.3 = 150.46 mm

  • P300, single-channel: 202.77 - 51 = 151.77 mm

  • P20, single-channel: 183.77 - 31.1 = 152.77 mm

  • P300, 8-channel: 192.44 - 51 = 141.44 mm

  • P20, 8-channel: 176 - 31.1 = 144.9 mm

How to use the X/Y/Z coordinates in a Python protocol

  1. You can use the code snippet below as a template to evaluate the absolute X/Y/Z coordinates of the OT-2.

    1. To do this, you can either 1) download the .py file here and proceed to step b or 2) copy and paste the following script into a source-code editor of your choice.

      from opentrons.types import Location, Point


      def run(ctx):
      ''' input x, y, z values here (in mm).
      # The coordinates are absolute
      # with reference to the bottom left corner of slot 1 as origin.
      # x, y, and z can be a float or integer
      loc = Location(Point(x, y, z), None)

      #pipette and labware
      tiprack = ctx.load_labware('opentrons_96_tiprack_20ul', '11')
      pip = ctx.load_instrument('p20_single_gen2', 'right', tip_racks=[tiprack])

      #commands
      pip.pick_up_tip()
      pip.move_to(loc)
    2. ❗ Important: Before you can use the script, you will need to modify it by using a source-code editor.

    3. You will need to include specific X/Y/Z values in addition to the pipette and labware in use where the script's instructions indicate. Note that pip.pick_up_tip() and pip.move_to(loc) are used for moving the instrument and picking up tips. When you are done, save it as a .py file.

    4. Finally, you need to run the script on your OT-2 using the Opentrons App. To do this, open the Opentrons App. After connecting to your OT-2, go to the Protocol tab and upload the .py file you modified and saved. Navigate to the Run tab and select Start run.

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