Pause a loop to refill a media reservoir

[thentropy]

*EDIT: I realized using my (IF =nsMedia<50000) is flawed! I set nsMedia to 160000 in the start tab so the software will never see nsMedia as anything other than 160000, it will never trip the Then/Else loop and I will always see the same error. So the new question is how to reference the volume remaining in the reservoir as its own variable that can define my IF argument?

Hi all, I need some advice on building a method on my second-hand Biomek i7 that features a pause step to trigger during a loop if the media reservoir gets too low. My method is a simple plate-filling method but will need to be agnostic with regards to how many plates are run per batch and which wells require a given volume.

I want to use the 96-multichannel head for all liquid transfer steps. My media reservoir has a max volume of 160 mL. I am using the “Select Tips” function for the user to choose which wells need to be filled at a given volume. The volume, in turn, is defined by a variable. Attached are some screenshots for additional details.

Crude deck layout. Ultimately, I want to pipette from both selective media and nonselective media, but for now, I’m only focusing on nonselective pipetting.

Reservoir properties are set to a “known” volume defined by =nsMedia in the Start tab.

My aspiration loop is simple and stops at =CulturePlates which, for now, is set to 5 in the Start tab.

The loop is triggered based on a button prompt asking if the user has any strains requiring a given volume. The screenshot shows successful aspiration through two plates but gets stuck without prompting a pause, even when I set a tolerance of 50 mL left in the reservoir and this error pops up regardless of that tolerance threshold.

While the loop logic makes sense to me, I understand it might not make sense to the robot. Do I simply have things a little out of order in my method or am I asking for something more complex?

For context, I am brand new to any and all automation as of a month ago and we don’t have any in-house expertise. Just winging things over here! Thanks for your time.

[evwolfson]

@thentropy

While the loop logic makes sense to me, I understand it might not make sense to the robot

Unfortunately, the robot is most likely right. However, it probably has some parameters being factored in that you are not privy to.

I haven’t taken a deep look at the script quite yet, but the first thing I’d confirm is if there’s an overage or any other volume loss occurring during the pipetting. You could also check labware state at the beginning and end of each loop to find reservoir volume and step through the loop one by one to make sure the mental math matches what is being calculated within the simulation.