Hi there!
I’m running a turbidostat experiment with an OD range between 0.3 and 0.4. Lately, some of the vials diluted below 0.25 on most of the dilution points, as you can see in the example image.
I investigated the first dilution shown in the image by looking at the log files of the experiment:
> vial12_OD.txt
1213.6906,0.39429070221265333
1213.6963,0.4109524298864022
1213.7026,0.4094942295435691
1213.7084,0.3998969724607819
1213.7141,0.3894536872018252
1213.7199,0.39720734036398103
1213.7257,0.4041455191221323 <- Median OD higher than threshold, triggers dilution
1213.7319,0.40601651020283563
1213.7376,0.40228337796725094
1213.7434,0.4118299634803643 <- OD is not going down
1213.7493,0.4070276668745741
1213.7559,0.40389433293285565
1213.7616,0.40590832613400446
1213.7674,0.3997904551511858
1213.7732,0.3977720608931868
1213.779,0.412122912499114 <- Second dilution triggered (see pump log)
1213.7847,0.34196214344147996
1213.7912,0.3112550659559478 <- OD finally goes down
1213.7975,0.31447281836132596
1213.8034,0.3151366065371684 <- Median OD near lower threshold
1213.8092,0.31395404864861215
1213.815,0.31231540699946164
1213.8208,0.3107401688522861
1213.8267,0.3005412338761119
1213.8326,0.31286092567611307
1213.8385,0.31194255639750196
1213.8448,0.23536777571092626 <- Unexpected drop in OD
1213.8506,0.2355128690272959
1213.8563,0.23556124336059703
> vial12_pump_log.txt
1212.0175,11.08
1213.7257,10.98 <- First dilution, matches OD file
1213.779,11.24 <- Second dilution 3 minutes later, not reflected in OD
1217.0274,11.13
1218.6229,10.97
1218.6765,10.69
1221.9519,10.79
1222.0062,10.7
> vial12_ODSet.txt
1212.0535,0.4
1213.7257,0.3 <- Time of first dilution (correct)
1213.8034,0.4 <- Median OD near lower threshold, file updated with upper threshold
1217.0274,0.3
All this makes me think that the pumps are diluting way after the command is sent, so there may be some kind of miscommunication between the client and the server. Any suggestions on how to solve this?
Thanks!