Opentrons / opentrons

Software for writing protocols and running them on the Opentrons Flex and Opentrons OT-2
https://opentrons.com
Apache License 2.0
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feat(api/smoothie): home should return an offset, like a probe #5873

Open theosanderson opened 4 years ago

theosanderson commented 4 years ago

Overview

Sometimes one would like to check where an axis is compared to where we think it is. For example, if we do a tip pick-up we have to home the Z axis afterwards. If we could return how how far the homed position was from the "expected" position then we could determine whether the user had forgotten to place the tip rack on the deck (homed position would be exactly "expected" position, due to no missed steps).

Implementation details

This appears to require changes to both Smoothie and the API so I don't expect it to happen anytime soon. Still wanted to record the idea which I think is pretty powerful. I think you could detect even missing individual tips, as well as checking for collisions where they are possible, etc.

┆Issue is synchronized with this Wrike Task by Unito

SyntaxColoring commented 4 years ago

This would also let us detect whether the home was preceded by a severe crash. (When the gantry collides with one of its end stops, the motor skips.)