Hello,
I have some question about the touch off function. I read the liquid handling reference guide and through the posts concerning this subject. As far as I understand, the function works with force feedback but I did not find what will happen, if no force feedback is detected (in case of largely differing labware properties). Is there a lower (height) limit where the function stops searching for force feedback? And how is this height related to the bottom definition of my labware?
Thank you in advance for your help!
Hi @FabienKohl,
In the case that no force is detected, the tip will travel until it reaches the expected inside bottom of the well (the Z-coordinate seen in the Adjust Location window of the Deck Layout Editor), and then lift off the distance entered into the pipetting step. For example, if a plate is taught to have a Z-coordinate of 190.0mm, the Touch-off Distance is set to 2mm, and the plate is never placed on the carrier, then the tip will travel to 190.0mm before lifting to 192.0mm and pipette. Note that if a container has a Max Pipetting Depth set greater than 0, then the tip will travel to this height and lift off without ever experiencing the force feedback.
Alternatively, there is a distance that the tip travels to before it begins seeking the bottom, which is the LLD search height of the well. In the case where a plate is sitting higher than this height, the tip will crash into the plate and return a Z-step loss error, instead of considering it to be a “found bottom”.
Thank you,
Dan
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Thank you very much for the clarification!