You can make sure your OT-2's positional calibration is accurate by running a Calibration Health Check. If it isn't, the check will help you identify which parts need to be fixed.
Calibration Health Check guides you through checking the accuracy of your OT-2's:
Pipette offset calibrations, for your currently attached pipettes.
Tip length calibrations, for the tips that you used to calibrate your attached pipettes' offsets.
It will not help you check the accuracy of:
Pipette offset calibrations for pipettes that aren't currently attached.
Tip length calibrations for tips other than the ones that you used to calibrate your attached pipettes' offsets.
Any of your labware calibrations.
Any of your custom labware definitions.
Required software versions
Make sure that both your OT-2 and Opentrons App are updated to at least v4.0.0.
In earlier versions, positional calibration and the Calibration Health Check worked much differently.
Opentrons tips in Opentrons tip racks, for each of your attached pipettes.
Your Calibration Block, if you have one.
Step 1: Begin
In the Robot tab, go to your OT-2's home page.
In the Robot Calibration section, near Calibration Health Check, select Check health to open the Calibration Health Check.
Can't find the "Check health" button? The button will be hidden if your OT-2 is missing a deck or pipette offset calibration. Look for "Calibration required" errors and resolve those first.
Step 2: Take measurements
Closely follow the Opentrons App's instructions.
You'll take measurements by manually jogging each pipette to positions designated by the Opentrons App. The Opentrons App will compare those measurements to your OT-2's current deck, tip length, and pipette offset calibrations.
Step 3: View the results and download the details
The Opentrons App will summarize which parts of your OT-2's positional calibration looked good and which parts looked bad.
(For background on what each of these parts does and what the differences are between them, see How positional calibration works on the OT-2.)
While you're here, download the detailed JSON Calibration Check summary. If you reach out to Opentrons Support for help, it will help us troubleshoot. You won't be able to download it after you exit the Calibration Health Check.
If all the checks found a good calibration
Congratulations: your OT-2 can accurately move both of its pipettes relative to the deck! ✅
As you continue using it, though, be on the lookout for other problems. The Calibration Health Check can't identify every kind of calibration problem.
If something still seems wrong even though all the checks passed, see if the problem is specifically mentioned in Troubleshooting movement, positioning, and calibration problems. Otherwise, reach out to Opentrons Support with the detailed JSON calibration check summary that you downloaded.
If some of the checks found problems
If there's a problem with deck calibration, recalibrate the deck.
If there's a problem with tip length calibration, recalibrate tip length.
If there's a problem with pipette offset calibration, recalibrate pipette offset.
Doing things in this order minimizes the extra work that you'll have to do because of how the different parts of calibration build on top of each other.
After recalibrating everything, run the Calibration Health Check again to make sure the problems have been resolved.
If you're still having trouble, reach out to Opentrons Support with the detailed JSON calibration check summary that you downloaded.