This article is about the OT-One.

It's no-longer sold or actively supported by Opentrons, but we've kept this article here to help existing users. Please see our OT-2 Support articles for the most up to date information!


Your robot's internal ruler may differ from the actual distance it is traveling after many hours of use. 

As a standard maintenance procedure run the X & Y belt calibration to keep your machine 

The X & Y belt calibration zip file contains binary files for both Mac and Windows operating systems. The binary file will run a pre-compiled python file it can simply be double-clicked to execute.


• Painter's tape
• Fine tip pen
• Metric ruler (millimeters) 

The button below will redirect you to the Opentrons' Github page


Step 1: Line your X axis rain and YR axis rail with masking tape
Step 2: Download the master zip file for the X & Y calibration

Step 3: Unzip the file

Step 4: Open the folder with the calibration files

Step 5: Run the calibration file specific to your operating system
Step 6:  Mark the origin position on the masking tape
Step 7: The program will prompt you to send the robot a certain distance in millimeters. For OT-Standards/OT-Pro send the robot 290mm for both the X & Y distance. The OT-Hood model is more compact and will not reach those limits,  send the robot 250mm for the X and 200mm for the Y distance.
Step 8: Mark the final position the robot travels
Step 9: Measure the actual distance traveled
Step 10: In the program insert the actual distance traveled measurement
Step 11: The program will adjust the robot's internal ruler accordingly
Step 12: Disconnect your USB and Power supply and reconnect

 Find the full video instructions on how to calibrate your robot's belts

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