I had to make some adjustments to one of our methods after discovering that our pipetting sequence would not work due to movement constraints of our independent channels. Therefore, we added movement of our 0.5mL Matrix Rack from the bottom of the deck to the center of the deck. (the tubes are uncapped and the rack also does not have a lid)
The teaching of the labware using the iSWAP was fine, but when I was teaching it kept saying that 11mm was the minimum grip height for the labware. I ended up keeping it that way originally when using the iSWAP Get Plate (Single Step) function. However, I noticed when picking up the rack, it would pick it up basically at the lip of the rack where the lid would sit if it had one. I think that’s a bit dangerous because I worry that the rack might slip out of the iSWAP if more samples are added due to the weight. When the rack was placed into the correct spot, there were no issues in the X and Y direction, but to reach the proper Z height, the prongs of the iSWAP would get caught on the lip and the iSWAP would get pushed up as it travelled down to set the labware into position.
Referring to the programmer’s manual, I increased the grip height to 13, but I’m still having the same issue (I’m wondering if the grip height is actually going the opposite direction).
How would I make it so it grabs the labware closer to the middle of the rack rather than at the very top? Also can you explain what other parameters to consider besides grip height? The only other thing I can think of is maybe the instrument is considering the labware with a lid on.
Since tube racks typically have containers that are much taller than the rack itself, this will increase the grip height needed to grip the rack itself. I would recommend a 20 or 25 mm grip height which should force the iSWAP to grip lower on the rack.
Also keep in mind that if you are using a carrier that has a high container bump, this will press up on the tubes, but not the rack as much since the containers are disconnected from the rack. This could also artificially change how low you need to grip because the rack is physically lower than the labware definition is expecting it to be. You can see this if you slowly place the tube rack down on your carrier as the tubes will make contact first before the rack bottom does.
This issue should be resolved if you are using the newer gray tab carriers as the z bottom for the rack and the containers are not as exaggerated as the older spring carriers.
Apologies for the late response, I was finally able to do some testing at 25 and it works much better! I might have to make some minor adjustments but overall it is a lot less concerning than before.
I notice that the teaching is slightly to the left as it’s putting the rack down, but I’m hesitant to make any adjustments since the pipetting seems to be ok at the position it’s at currently. I think we have other programs where the teaching is a little off when transporting a variety of different plates and racks. Is there anything to worry about? We do have the newer plastic tabs on our carriers so it seems to hold the labware in the correct place anyway, but just wondering if perhaps I should still reteach it slightly to avoid wearing out the plastic tabs.
