The front two channels on my eight-channel are not doing the same liquid class as the rest of the channels. What could be causing this?
I’m not aware of any expected behavior that would explain this issue outside of a potential programming error. Please provide a method, trace file, and usb com trace file so we can help troubleshoot!
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Here’s a video, notice the front two channels are not mixing. This behavior occurs every time. The channels perform normal aspirations as expected.
Trace file:
2025-05-07 14:41:53.339 Microlab STARlet : 1000ul Channel Aspirate (Single Step) - start;
2025-05-07 14:42:06.027 Microlab STARlet : 1000ul Channel Aspirate (Single Step) - complete; > channel 1: culture_plate, A1, 10 uL > channel 2: culture_plate, B1, 10 uL > channel 3: culture_plate, C1, 10 uL > channel 4: culture_plate, D1, 10 uL > channel 5: culture_plate, E1, 10 uL > channel 6: culture_plate, F1, 10 uL > channel 7: culture_plate, G1, 10 uL > channel 8: culture_plate, H1, 10 uL
2025-05-07 14:42:06.027 Microlab STARlet : 1000ul Channel Get Last Liquid Level (Single Step) - start;
2025-05-07 14:42:06.074 Microlab STARlet : 1000ul Channel Get Last Liquid Level (Single Step) - complete; > channel 1: 0.0 mm > channel 2: 0.0 mm > channel 3: 0.0 mm > channel 4: 0.0 mm > channel 5: 0.0 mm > channel 6: 0.0 mm > channel 7: 0.0 mm > channel 8: 0.0 mm
2025-05-07 14:42:06.137 USER : Trace - complete; Aspirate step return 1:0[01,00,00,0,10.0,culture_plate,A1[02,00,00,0,10.0,culture_plate,B1[03,00,00,0,10.0,culture_plate,C1[04,00,00,0,10.0,culture_plate,D1[05,00,00,0,10.0,culture_plate,E1[06,00,00,0,10.0,culture_plate,F1[07,00,00,0,10.0,culture_plate,G1[08,00,00,0,10.0,culture_plate,H1
2025-05-07 14:42:06.137 USER : Trace - complete; Aspirate step return 2:0.000000;0.000000;0.000000;0.000000;0.000000;0.000000;0.000000;0.000000
2025-05-07 14:42:06.137 USER : Trace - complete; Aspirate step return 3:-1.658288;-1.658288;-1.658288;-1.658288;-1.658288;-1.658288;-1.658288;-1.658288
Firmware commands:
< 14:41:53.496 8AF#8000#00: C0RXid0246
> 14:41:53.517 8AF#8000#00: C0RXid0246er00/00rx+03430
< 14:41:53.520 8AF#8000#00: C0ASid0247at0&tm1&xp03430&yp1460 1370 1280 1190 1100 1010 0920 0830th2450te2450lp2001&ch000&zl1881&zx1871&ip0000&it0&fp0000&av00100&as1000&ta050&ba0000&oa020&lm0&ll1&lv1&ld00&de0020&wt10&mv01000&mc01&mp000&ms0750&gi000&gj0gk0zu0113&zr09285&mh0000&zo000&po0100&lk0&ik0000&sd0500&se0500&sz0300&io0000&il00000&in0000&
> 14:42:05.871 8AF#8000#00: C0ASid0247er00/00
< 14:42:06.027 8AF#8000#00: C0RLid0248
> 14:42:06.074 8AF#8000#00: C0RLid0248er00/00lh+0000 +0000 +0000 +0000 +0000 +0000 +0000 +0000
< 14:42:27.908 8AF#8000#00: C0RXid0249
> 14:42:27.923 8AF#8000#00: C0RXid0249er00/00rx+03430
< 14:42:27.923 8AF#8000#00: C0DSid0250dm3&tm1&xp03430&yp1460 1370 1280 1190 1100 1010 0920 0830zx1871&lp2001&zl1881&ip0000&it0&fp0000&th2450te2450dv00100&ds0750&ss0560&rv000&ta050&ba0000&lm0&zo000&ll1&lv1&de0040&mv00000&mc00&mp000&ms0750&wt00&gi000&gj0gk0zu0113&dj00zr09285&mh0000&po0100&
> 14:42:33.526 8AF#8000#00: C0DSid0250er00/00
< 14:42:33.667 8AF#8000#00: C0RLid0251
> 14:42:33.714 8AF#8000#00: C0RLid0251er00/00lh+0000 +0000 +0000 +0000 +0000 +0000 +0000 +0000
Hi Stefan,
The mixing function (cycles, volume) is not part of the liquid class. Just the mix flow rate. The firmware calls appear to be correct in terms of the parameters. You can look at the plungers up above to see if they are at least moving and are consistent with the other channels. If they are, then it may be an issue with the stop discs on those channels.
I’ll follow up with you separately to gather more info and materials.
Thanks,
Eric
Hi @Stefan ,
Has the system passed daily maintenance?
I will give that a shot next time im in lab. Thanks!
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@BrandonBare_Hamilton @EricSindelar_Hamilton
Update: Looks like daily maintenance passes for the tightness checks and I can definitely see the plunger screws moving. It’s odd that some of the channels aren’t working correctly only on the mixing step, and the aspirate works fine. Seems pretty likely that this is an issue with how the command is being run, maybe labware geometry/ liquid height as well. I will run some more tests and update with my findings.
Looks like the problem was that the two problem channels were right against the bottom of the plate and the pipettes were forming a seal, and no liquid was getting in. For whatever reason this wasn’t a problem during the actual aspiration, and it never happened for the other channels. Increasing the liquid height fixed the problem completely.
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