PAL RTC Autosampler Issue

Hi, does anyone have experience using a PAL RTC autosampler on their Agilent GC? Recently I've been encountering an error message in Chemstation saying "collision occurred on Z drive 1, force limit exceeded" which aborts the run. Any idea how to resolve this? I've rehomed all the drives and calibrated the unit several times with no success. 

  • Rufus,

     I have moved this to the Gas Chromatograph forum.

  • I have been having the same issue. It only started after I changed the liner and the septum. Then when I started my sequence this error would show up each time the arm went to return the vial to its position. Have tried turning the system off/on, re-teaching all modules, switching out different tools and methods. Sometimes I would get through 5 or 6 successful injections then another error message pops up "Unexpected collision occurred." I'm currently at a loss so any help would be appreciated. Also curious if you found the source of the problem/solution. 

  • I did find a solution, though probably not the optimal one: I removed the housing from the sampler arm itself and it seems to operate fine now. I still haven't identified the exact source of the problem, but it seems to be a mechanical issue with the sampler arm itself. My guess is something inside is loose enough that it is making contact with the housing and putting force on it when the arm moves up/down. Try operating without the housing and see if that helps! You'll also be able to see how the internals are functioning as it does its thing.

  • Thanks for this. I didn't quite get to removing the housing, I just reset the PAL and the Z Drive error went away. However, now we are consistently getting an "unexpected collision occurred" error, which I believe could be due to the crimp caps I'm using. It happens when the robot arm is bringing the vial to the agitator or back to the vial tray, and the cap is just slightly mis-aligned to the point where the vial won't fit in the tray anymore. I'm currently testing out a new set of vials. 

    I've got a service call put in with Agilent to determine the root cause and whether the two errors are related. This whole thing started with the Z drive collision error so I think they must be. Agilent seems to think it might be a motor issue. Will let you know if we figure it out. 

  • Hello  and  ,

    That type of error could be caused by multiple issues, such as:

    - Sticky syringe that prevents free motion.
    - Faulty Z motor. 

    - Possible improper installation of the tool or the head portion of the sampler.

    I would also make sure that you have the correct syringe type/size configured on the sampler. Not sure if that could cause this particular error, but it's worth checking.

Was this helpful?