Temperature control stopped working


After many successful eVOLVER runs in the past, the temperature control/heating elements for all 16 sleeves suddenly stopped working. To troubleshoot, I restarted the sleeve platform, restarted the GUI, restarted the experiment file, and the temperature seemed to recover reaching about 34C, and then decreased again to 24C, about room temp (see image below). I have not made any updates to the software or hardware, and in the past all 16 sleeves have been very consistently at the set point of 37C up until today.

Any ideas? Thank you for your help!

Hi Katie,

Sorry to hear! Can you send a screenshot of the server log? Ssh to the RPi and run sudo supervisorctl followed by tail -f evolver. Let that run for about 40s then take a screenshot.

It could be a hardware problem but want to rule out software first.


Does it seem like the motors for stirring are behaving normally? The stirring and heating are powered by the same power supply. So if it is a power supply issue, it might be more obvious looking at the stirring.


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Thank you Zack! I have an intermediate question. I was able to ssh into the RPi, but it looks like I may need to install sudo? I wanted to ask you about how to do that, since I am not as familiar with installations to the RPi directly. Should I think of it like the PC, and maybe use something like: “py pip install sudo”?

Good idea. I can see the stir bar spin for a few seconds when I first start the experiment file, and then it stops. Do you think it makes sense to replace the power supply?
Thank you!

You should just run sudo supervisorctl with no python in front

It seems to me like theres an issue with the power supply. How long does the stirring stay on, is it consistent with the temperature shutting off?

If you lift the lid of the machine, by unscrewing the front two screws and lifting the top plate, you should be able to see two rectangular power supplies. The bigger one is the 12V power supply that is responsible for stirring and heating. You can monitor the green LED on that power supply when you switch on the system to see if there are any odd behaviors. The LED should stay on and not flicker during use. Make sure to stay safe when doing this by not touching any of system while it is turned on.

If you change out the power supply, follow all best practices for dealing with electronics (e.g. power down, wear gloves if possible) make sure you are very careful at reconnecting the wiring harness to the proper screw terminals.

Using simply: sudo supervisorctl, I got the following result:

The stirring and the temperature timing do seem to be consistent with each other. Just now, neither are turning on at all after restarting everything.
The green light on the 12V power supply stays on, but does seem to have a very very slight flicker. Should flickering that indicates an issue be very obvious (I know that is hard to answer, just trying to evaluate what I am seeing)?
Thank you!

Do you have a multimeter to measure the V- and V+ terminals on the 12V power? If so, what is the reading?


Unrelated, but I think you should increase the serial_timeout field in the conf.yml file to something like .8 or so. It looks like the pump command is timing out from the log you posted.

The multimeter shows 12V consistently coming from the power supply, with an experiment file running, and the heating and stirring not working. So it seems like the power supply is likely ok, right? Any ideas of more things to check?

This time, when I first started a new experiment file, the heating and stirring did work again for about 2 minutes before stopping. So it seems that the heating/stirring are occasionally benefited by restarting an experiment file, but only for a minute or two.

Thank you!

Thank you Zack! I will take a look at that. I am running with a different pump right now, so hadn’t been looking at those parameters.

Can you record the supervisorctl status (like before) but this time try updating the temperature and stir commands with the eVOLVER GUI while recording. Can you record the output for a few cycles ~ 2 minutes, and then link us to the output after?


Also, can you be very sure that no other programs are running the eVOLVER code? Maybe restart the lab computer just to be sure. I want to avoid the scenario that two programs are sending commands to eVOLVER.

I rebooted the PC, opened the GUI only, then changed the stirring for 12 of the vials, then changed the temperature for 12 of the vials. I emailed you the supervisorctl file for it.
Thank you for your help!

After you changed the stir rate to a higher setting, do they behave normally?

No, there is still no stirring at all.

I still think that the most likely culprit is the power supply.

Do you see any scorch marks/corrosion on any of the electrical components or the motherboard? If not I agree with Brandon.