I’m using cLLD on a Hamilton STAR to detect liquid before aspiration. My samples are in flip tubes, some placed in the cooler (HHC) and others in the blue flip-tube racks.
I noticed that the minimum volume required for detection is very different:
In the cooler, cLLD works fine even with small volumes.
In the blue racks, cLLD does not detect liquid below ~500 µL, which is too high for my stock solutions.
My question: is there a way to change or calibrate this behavior so that cLLD can detect smaller volumes in the blue racks?
I would recommend checking the taught Z bottom of the tube in the blue tube adapters. Typically, these have excellent grounding for cLLD. If the Z bottom is set too high, then you will start to get Liquid Level errors before the bottom because the channel thinks the bottom is higher than reality.
My recommendation is to teach the position so that the Z bottom is set with a very slight touch to the bottom of the tube and then set the container “Maximum Pipetting Height” to 0.5 or 1 mm to prevent pinching the tip for low volumes.
If you can send a picture of what the tube looks like in the insert, that would be helpful as well along with other details such as what specific liquid level error you’re getting (Insufficient Liquid or No Liquid Level found), what volume you’re trying to aspirate, etc.
Here is the rack with the inserted flip tube. It seems that the pipette is not reaching the bottom, which leads to the “No Liquid Level Found” error. I’m trying to pipette 15 uL of water with 35uL intial in the tube.
The seek height and the clearance height both are set really small (2mm from the bottom of the tube). This could explain your cLLD issue as the search is beginning in the liquid. To you it would be just going directly in the tube. You want the seek to start above the tube, so the value should be the full depth of the tube + a little above. The default definition of this tube has the seek height set to 40 mm and the clearance height set to 70 mm.
Hello Brandon! Thank you for your help!
I just tried with your values and got the same result. I can see that the 50 µL tip goes deep into the tube, but it still doesn’t detect any liquid.
Can you confirm the container that was updated was for the flip top tubes? The rack definition you showed was for the CPAC adapter, not the sample tube carrier.
If the container was correct, you may have to close the layout and open back up for changes to take place.
You will know it updated if you see the the channel move fast, then briefly pause and use a slower speed above the tube for the cLLD search.
Can you also confirm you cLLD sensitivity in the aspirate step?
Hello @BrandonBare_Hamilton ,
I saved the Ham_24_RB_TuR_1.5ml rack from the ML-STAR library. I believe I have the correct rack (I’m opening the tube with the same sequence).
I’m using the cLLD sensitivity from the labware definition, which is set to High.
