Hello,
I received an unexpected Hardware Error, saying something about pLLD and «E:P1:02/72» in only one Channel.
I did not change anything and I am using cLLD so why does the robot tell me that something is wenig with pLLD?
The method has been Running for multiple times and this seems just random.
Can anyone help me understand The Error message?
Can you share a snippet of the trace file when the error occured?
If I remember correctly, I observed this type of error after liquid was aspirated into a channel and lead to misreadings in the pressure sensor. 
PX72 - PIP - Liquid Level Detection - Auto calibration at pressure Sensor not possible - Hardware not working
This is a good indicator that the pressure sensor inside the pipette is giving intermittent readings.
Even though the system might not be using the PLLD it still checks to make sure they are active and functioning properly as a basic internal housekeeping task.
Does it pass Daily/Weekly maintenance? What if you run it a number of times?
This can happen when over aspiration has occurred as well as long term (years and years) use with very volatile substances.
This will most likely require a replacement pipette, sooner than later.
the trace file just says this: «E:P1:02/72»
Interesting. We just recently had the yearly PM, but everything passed and went fine and other methods work without a problem.
We only do daily maintenance on a weekly basis, as recommended by Hamilton due to sample size/volume. The last one on monday passed, but I can run it again before I try again next time.
I did open the method in run control, then opened it again, first then I pressed the “play” button. Could this get the instrument initialization confused?
I was aiming for the context when this error occured to see what happened before.
But I second @JDesRo answer.
What I also do: cross check the pressure readings from daily maintenances before and after PMs.
Context:
using 1000 uL channel to pipette 50 uL standards solved in methanol with 50 uL conductive filter tips.
cLLD active, tip goes down 1.2 mm after cLLD detection, mixes 4 times and then goes over to surface dispense in 450 uL serum tubes.
Mixing and aspirating went fine, but surface dispense threw an error only in channel 1. Channel 2 - 7 (channel 8 was not used) worked fine.
Thought first that the tip might have gone too low in the mixing/aspirating step, since there was not much volume, but after volume inspection of the solution I could see that other standard-solution had even less volume.
I am going to check the pressure readings from daily maintenance before and after I perform the next daily maintnance.
Where can I find them and what should I be observant of?
It’s the easiest, when you use the HxUsbComm*.trc and look for “P1RP” (for channel 1) and plot the value after “rp”.
Of course make sure, that you don’t use values from pressure reads during your methods - if you included such steps.
Larger deviations are already a hint that something might be off. Of course you need data from the past to get an idea, what a “large” deviation is.
This usually means the pressure sensor needs to be recalibrated or the head has to be replaced. Your FSE may not have done the adjust/check pressure sensor.
If you have a contract get them back in to run it and or replace the head.
If you have paid PMs and not under contract the sensor o-ring can be cleaned with that pipette head removed. Shoot me a DM if you need details.
I’d recommend using a more descriptive title than “Hardware Error” in the future, it will help people know whether its something they can help with. I changed the title already btw
We got the Channels Checked and there was no pressure Problem whatsover.
Channel 1 was even tighter than other Channels.
@BrandonBare_Hamilton made me aware of that I was using Channel 1 way more than other Channels in this particular method, so I modified the method to use 3 Channels instead of 1, so that there Are less Repetitions on Channel 1.
We have not observed the Error again, so we continue to believe that everything is ok until then.
Thanks again for the help!
Error 72 during daily/weekly is due to slight overpressure in the pipetting system after Tip Pick Up. As the Teaching Needle is closed, a slight overpressure can build up if there is a movement of the Teaching Needle towards the Pipetting Head after the Pick Up. I would run PXBP single command to see if any there is any error. I would check the pipette head sleeve or replace the pipette head.
Error 72 is thrown when the channel (head) is trying to re-range the pressure sensor for an aspirate or dispense. They can be randomly intermittent, and usually are solved only by a head replacement.