EVO - Weird behaviour - Well positions shifted after adding subscript

Hey folks,

we are encountering a strange problem with our Tecan EVO. We have a script that has been running perfectly for a long time. Then someone implemented a minor change (added a subscript to read a barcode) and since then our well positions are incorrect. This means, the pipette tips are not only in the wrong well, but also not even in the center of the wells.

What we tested so far:

  1. Teaching of the worktable for the plate - Outcome: Teaching is correct.
  2. Making a new script with the same worktable and a simple pipetting step. - Outcome: Works fine.
  3. Tested old script (without barcode reading). - Outcome: Works fine.
  4. Started only part of the script with the pipetting command. - Outcome: Works fine.
  5. Saved the worktable that has been working under a new name. Copy and paste the script and all subscripts under new name, using the new worktable template. - Outcome: Strange behaviour still exists.

Does anyone have any idea what could be the problem?

Thanks a lot and best regards,

this does sound v odd,
to analyze, you would need to provide EVO logfiles to compare the movements between the functional script & the strange behaviour script

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I’ve seen something different, but had similar results - possibly it’s related?

When plates are transferred to something like a Te-Shake or other device, the device can be told what plate type is loaded into/onto it. If a subsequent plate movement goes from device → back to original labware position, the labware definition will use the type set within the shaker command rather than the actual position. Is it possible that in the subscript, the plate type is being changed and is persisting over to the next commands being run?


What are the steps in the subscript? Are you setting down / picking up the plate somewhere?

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Thanks everyone for your suggestions - you were definitely pointing me in the right direction! In the subscript the plate is transported from a hotel to its pipetting position - on the way there the barcode is read. The symbol reader was set with a different plate definition (the default plate), which led to the strange behaviour. So exactly what @evwolfson described - thanks a lot for you help! This forum is simply awesome :-). Have a great day.


Congrats on solving it!