Sometimes when I use the quad grippers on my Vantage system, the grippers will refuse to pick up the labware randomly. I was wondering if anyone knows how have error handling for situations like these? I initially wanted to use the “begin error handling by user” command but the gripper steps do not contain any return values for errors. Anyone have any suggestions for this?
@pavster - Do you happen to have any error details or specifics when the QCG get plate step errors? That will make it easier to follow up with better advice.
We have some similar problem where the connectors to plate for sensing plate is not working and that cause the problem sometime. Is this something u r facing? We are using some firmware commands to overcome this problem
Hi Nick And Kalpesh,
Thanks for replying! For the specific errors, typically, the grippers will pick up the plate and give a “labware was not found” error even though the plate has already been picked up. Also, sometimes it will pick up the plate and then drop it and give a “labware lost during transport” error.
Kalpesh, it seems like we have a similar issue. What firmware commands are you using to combat this?
The ‘labware not found’ error after plate pickup indicates an issue with the labware detection feature of the QCG. This feature relies on tabbed sensing brackets that run down the center of the QCG grip fingers, which use the channel cLLD functionality to detect when a plate is present within the gripper.
For this feature to work as intended it is important that the four CORE adapters (the holes that the channels descend into to grip the QCG) are clean and free of debris. These can be rinsed with isopropanol or ethanol and wiped dry. Additionally, it is important the the sensing side brackets are not bent, and flush to the backs of the fingers when relaxed, with the tab centered and not making contact with the side of either finger. You’ll also want to check that the screws which mount the side bracket to the body of the QCG (and help maintain the connection with the channels for cLLD) are not loose.
All that said, as Kalpesh mentioned this feature can be turned off with a firmware command. This will prevent any unwarranted labware detection errors and issues, but will disable the channels from detecting if labware is mishandled during transport. Ultimately the choice to leave it on or off is yours. To turn it off you can use the following firmware command in VoV:
This will turn of plate detection permanently, even through instrument powercycles until it is re-enabled. To re-enable, send the following command:
Regarding plates being dropped or otherwise mishandled during a place plate command, this indicates that the grip parameters are not optimal for the the labware being transported, and/or the labware being gripped may need to have its deck coordinates re-taught. Without seeing the transport myself, I cannot tell you exactly which parameter(s) needs to be fine-tuned, but in addition to checking the deck teaching, you likely need to adjust some combination of grip height, grip width and grip strength in the get plate step.
Hope this helps. Thanks.
Hello @pavster ,
if these do not work then go to old school and just bend that metal plate a little bit and then it works for us. Also we tried to put some lab tape and that also make it better.
Thank you both for your help! Is there any firmware commands to reduce the sensitivity of the grippers instead of turning off the sensing completely?
I would also love to know if this exists, please and thanks!
The firmware command that Nick listed above sets a threshold value, so the number following the ‘bl’ parameter can be modified to any integer between 0 and 100. Setting a lower, non-zero value may improve results without disabling detection altogether.
I see this now, thanks a lot!