Hi everyone,
I know there’s a similar thread but wanted to post a new one to see if anyone had a similar issue. It’s a TECAN Fluent 780. It’s relatively low volume usage - only two routine runs per week - both runs this week executed normally with no issues.
today, the tech is doing an additional run and getting this error:
‘The run was stopped due to a non-recoverable error:
Over current (short circuit) detected while moving (Arm: LIHA Axis: x)’
The action at which this is happening is when the FCA arm is going to pick up tips and it is at the entirely wrong spot on the deck.
We are in Edmonton, AB - a very dry place with a lot of static. The previous thread I found with a related error found their issue to be moisture buildup due to humidity. I don’t know what we could do about the static, though. We’re waiting for tech support from TECAN so hopefully they can guide us through what to do next.
Any help or suggestions much appreciated though! Thanks!
If it’s static, they’re not going to be able to help you much.
You can also query temp & humidity on newer Tecan Fluent’s maybe you should query them at run time in your scripts so you can start to associate these errors with specific spikes.
What concerns me is that the arm isn’t in the correct place to pick up tips. Although, perhaps the error happens while the arm is trying to get to that location. My first line of troubleshooting would be to cycle the power and let it completely reinitialize itself. If there’s a physical problem with the arm you should be to find it with a power cycle (i.e. it won’t initialize at all).
A long shot, but you could try to wipe the front roller path of the FCA arm to clear up the roller from dust. In infrequently used instruments or 2nd hand instruments, dust can collect in that groove and can build/collect into an obstacle large enough to inhibit rolling. This adds torque, which can lead to lost steps for the X motor. Unfortunately this can also damage the wheels or create flat spots if this goes on long enough. Visually check for obstructions in the path with a phone camera or something in the back AND front guiderails. You’d be surprised, sometimes tips and tools get stuck in there since it’s a common spot to put down tools like hex wrenches. I found a nickel back there once when I was an FAE.
You may be able to check the X-motor by going into free move mode (I forget the actual name) and moving the arm to various positions and check if the steps are correct. Each grid position is one inch, so just convert that into 1/10 mm and that should reflect the X position you see in the GUI.
If the step differences are correct, then it could be the motor failing. You could potentially confirm this by slowing X acceleration or max speed in case there’s an overcurrent at super fast speeds. I can’t recall if that’s something that can be done outside of service for the Fluent.
If the steps are incorrect, then its possible that a sensor or physical obstruction is the problem. If sensor, call Tecan.
If physical obstruction is the suspected problem, you’d expect this to happen in just about the same X location every time (Like around the tip pickup) This would make sense if that’s a common end vector as that is where dust/debris in the track would be pushed and left to accumulate over may runs.
Thanks all. TECAN service will be in to take a look and hopefully repair.
I have actually left this lab so can’t try the suggestions like to wipe the front roller path of the FCA arm but I will pass that on to the lab. I have found in the past the TECAN service isn’t that interested in explaining things to the lab staff but I will encourage the lab scientist there to try to get as much information from the TECAN service person as possible.
I am pretty sure it’s not a physical obstruction but I will suggest they look at that as well.
I will update this post once I hear from my friends back at the lab what the solution/fix was.
Thanks again, all, for your suggestions and thoughts!
Power was cycled numerous times! That was my first suggestion as well and the lab tech said she’d already done that 3 times - and she also moved the arm while the instrument was off to try to force it to initialize but that didn’t do anything either.