In this section, you'll attach a pipette to your OT-2.

Your OT-2 has two pipette mounts. Each pipette mount can hold one Opentrons pipette. The pipette screws into the mount, and the OT-2 controls the pipette electrically through a cable.

Left picture: the left mount with no pipette attached. Right picture: the left mount with a P300 Single-Channel GEN2 attached. In both pictures, the right mount is raised and hidden from view.

Before starting

Determine if you have a GEN1 or GEN2 pipette

Some of these steps change depending on whether your pipette is GEN1 or GEN2. If you're not sure, see: Do I have a GEN1 pipette or a GEN2 pipette?

Gather required materials

  • You'll need one pipette screw, included in a small plastic bag with your OT-2.

  • You'll need a 2.5 mm hex screwdriver, included with your OT-2.

  • If you're attaching an 8-Channel GEN2 pipette, you'll also need your Calibration Block. The Calibration Block came in its own box, shipped along with your 8-Channel GEN2 pipette. Note that individually purchased 8-channel pipettes don't come with a calibration block. If you are interested in getting one, please contact support!

Step 1: If you need to, prepare your older OT-2 for GEN2 pipettes

If you're going to attach a GEN2 pipette, and you have an older OT-2, you might need to make a hardware adjustment.

Check when your OT-2 was manufactured. If it was before 2019-09-05, follow the steps in Preparing older OT-2s for GEN2 pipettes before continuing here.

Step 2: Lower the pipette mount for access

In the Opentrons App, go to the Pipettes & Modules page for your OT-2.

Select Attach for the mount that you want your pipette to go on. The gantry will move towards the front window, and the mount will lower.

Step 3: Select which pipette you'll attach

From the dropdown menu in the Opentrons App, select the model of pipette that you want to attach.

Tip: If you have both a GEN1 pipette and a GEN2 pipette to attach, attach the GEN1 pipette first. Otherwise, space limitations might make it difficult to squeeze into place.

Step 4: Align the pipette to the mount

Pass the pipette into the OT-2 through the front window. Hold it vertically somewhere behind the lowered mount.

Slide the pipette towards you, keeping it vertical. The connector on the pipette needs to match up with the connector on the mount.

Tip: If you're having trouble, getting low can give you a clearer view of the pipette mount.

The front edge of the pipette should be even with the front edge of the mount.

If your pipette is a GEN2 pipette, it should feel like it's hanging off of a hidden ledge.

Hold the pipette in place.

Troubleshooting: Pipette mount not lowering far enough?

Starting on software version 4.0.0, a known issue causes the pipette mount to sometimes not lower far enough. With this bug, the OT-2 needs a bit of help from you, so you need to pull it down with your hand until the white connector cable is visible. An example of the pipette mount not lowering enough can be found in a video below. This will be resolved software version 4.2. If you are unable to lowering it by hand sufficiently, please contact us at

Step 5: Screw the pipette into the mount

Note: If you are using an 8-Channel pipette on an OT-2R, you will want to ensure you are using the correct bottom pipette attachment screw which is shorter than the one used for the OT-2. Otherwise, your 8-Channel pipette will not be able to eject tips.

A total of three 2.5 mm hex screws will secure your pipette to its mount. There are:

  • Two top screws, which are permanently embedded in the transparent plastic at the top of the mount.

  • One bottom screw, which you need to insert yourself. Several bottom screws came with your pipette or OT-2, packed in a small bag.

Follow the Opentrons App's instructions to screw in all three screws.

If you're attaching an 8-Channel pipette, leave them slightly loose; you'll tighten them in a later step.

Two top screws:

One bottom screw:

Step 6: Connect the pipette cable

After screwing in the pipette, you'll need to plug it in. Your OT-2 will control the pipette through a white ribbon cable.

Find the white connector tab and press it in, towards the pipette, as far as you can. You should feel it plug in to the pipette.

Step 7: Check the pipette connection

Next, you'll make sure that the OT-2 can communicate with the pipette over the cable that you just plugged in.

In the Opentrons App, select Have robot check connection. Your OT-2 will test the connection automatically.

If all goes well, you'll see a green checkmark. But don't move on just yet!

Troubleshooting: Not getting a green checkmark?

If you see an "Unable to detect pipette" error message instead, see: Troubleshooting pipette connection problems.

Step 7: If you're attaching an 8-Channel pipette, level it

8-Channel pipettes are especially sensitive to tilt. If you're attaching one, some extra steps are needed to make sure it's attached perfectly straight. (To learn more, see Leveling 8-Channel pipettes.)

If you're attaching a Single-Channel pipette, skip ahead to the next step.

If you're attaching an 8-Channel GEN1 pipette

  1. Use your hand to gently and slowly pull the pipette all the way down to the OT-2's deck.

  2. Wiggle the pipette so that all 8 of its nozzles touch the deck at the same time.

  3. While holding the pipette down, tighten the 3 screws.

If you're attaching an 8-Channel GEN2 pipette

You'll need to use the Calibration Block shipped with your pipette.

Follow the Opentrons App's video instructions to use the Calibration Block to level your pipette. Remember to tighten the 3 screws when you're done.

Troubleshooting: Can't level the pipette completely?

You might have trouble leveling the pipette perfectly. You might not be able to wiggle it quite far enough to get all 8 channels to touch the surface at once. Or, even if you can, the pipette might spring back a little bit after you tighten the 3 screws.

If the difference between channels is less than 0.15 mm, it's level enough (0.15 mm is the thickness of between one and two sheets of typical printer paper). If it's more than 0.15 mm, and you're unable to correct it, your OT-2 might need more adjustment. Contact Opentrons Support for help.

Step 8: Finish up

You've successfully attached a pipette to your OT-2!

If you're setting up this OT-2 for the first time

If you're setting up your OT-2 for the first time, select Exit without calibrating to return to the Pipettes & modules page. You'll have some other things to do before you're ready to continue to pipette offset calibration.

You might see a warning here that says, "Pipette offset calibration missing. Please calibrate offset now." If you're setting up your OT-2 for the first time, ignore the warning—you'll come back to it later.

If you're attaching a new pipette to an OT-2 that's already set up

If you're attaching a new pipette to an OT-2 that you've been using, and the OT-2 already has a good deck calibration, select Continue to pipette offset calibration and see Get started: Calibrate tip length and pipette offset.

Troubleshooting: Can I remove a tip from a pipette manually by hand if I am unable to eject it?

Yes, this will not damage the pipette or the robot.

Next steps

You can come back to this page in the Opentrons App any time to add, remove, or swap pipettes.

If you have a second pipette, you'll need to repeat this process for that one, too, with the other mount.

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