Recently when dispensing to robo-columns with our Tecan fluent we have been running into contouring errors. I cannot find any documentation on what a contouring error actually is. Here is the error extracted from a snapshot:
Our current hypothesis is that the channels are getting blocked and this is an over current error of the syringes? We have noticed that when these errors occur the offending syringe is not fully in the zero position and appears “stuck”.
A contouring error in general is like a deviation between the actual position and the expected/referenced/desired position where the part shall drive. (For a general explanation, an internet search for “Contouring error” will lead to better definition than I could give).
I think the term contouring error on the Fluent can occur for every arm, I have seen the term Contouring Error for example when FCA or RGA unexpectedly drives into a labware. Basically that matches the observation that the syringe (channel 3 ?) did not drive to the expected position. Probably it’s a hardware issue that the diluter or the motor of the diluter is blocked when it moves.
Yep most contouring errors are actual collisions which meet force limits set in the config or simulated contouring errors to avoid collisions. The latter tend to occur because of poor setups (heights, micro script movements) and software definitions.
From day one our instrument would fail mid-run for various contouring errors from the Robotic Gripper Attachment/Arm (RGA). Turns out our “slip-ring” was bad. Horrible name, but the slip-ring is actually the communication cable the runs through the maze of machinary from a communication block all the way to the RGA head. This was replaced about 2 weeks ago and we haven’t had a problem since!
Contouring Error: Axis G - this was a gripper distance error
But as others have pointed out, it generally deals with the system expected something to be in a particular position, yet it is not according to a stepper motor/drive/soleniod/etc.
if you perform the same robo column run WITHOUT columns, does the system show the same error?
i’ve seen similar issues with our OptimizeCHROM method on a Fluent, and integrated pressure/flow sensors to better understand the chromatography flow characteristics per column to prevent/avoid these situations,
“contouring errors” is a fancy way of saying “I couldn’t get to my target position” - and applies to all mechanical actions
Thank you all for the information! I am used to not being able to google errors for lab automation instruments, I didn’t think to google “contouring error”. Odd that it is not referenced in the manual once!
We have seen this on a single syringe, no matter the order of the robo-columns or new robo-columns, we have not tried without robo-columns. We have also noticed for some time that the offending syringe, P3, was not zeroing even after daily maintenance and flushing. It then after some time seems to have fixed itself.
It is so intermittent it is hard to pinpoint if its a column issue or not.
I can’t speak for the Fluent but on the EVO we would tighten the knobs and run ethanol flushes to get everything out. We also would “prime” the syringes at the start of every day. Finally I would not hesitate to swap out components. Sometimes you get bad parts and it’s faster to swap it and see if the problem follows the component.
On the Fluent you can query the positions of channels, I wonder if you could do the same for the position of syringes.
With that said, Fluent’s setup may be different than the EVO’s.
This problem is making me take a stroll down memory lane lol.
We ran into this problem again today when dispensing to a new set of robo columns, same syringe P3. Hitting retry twice cleared the error. Syringe was lagging behind.
I believe it to be a combo of a bad syringe and too much back pressure when dispensing to the columns. Hopefully we can get a service member to check out the syringe soon.
Woah, just re-reading this, what does tightening the knobs do?
I see this in the manual, but it doesn’t explain what it does, or if over/under tightening can mess up the syringe? What is the “correct tightness” haha
Yeah so pretty much every thing in that picture that can be tightened should be tightened and/or checked every day. I believe it’s finger tight since it’s metal on plastic for the 3 way valve.
@luisvillaautomata Awesome, I hand tightened them! There was a bit of play on channel 3, 7, & 8. Good to know, need to re-read the manual for weekly/daily maintenance. We are very hesitant to work on the instrument due to being in Canada our service takes a while, don’t want to break anything that could stall our processes.
