Brewblox fermentation settings

Hi there

Long time BrewPi user here.
My first brew in 8months was yesterday and before that I installed brewblox on my rp3 and spark v2

On brewpi the temperature regulation was spot on. Never overshooted and just was on point.

I’m now about 6 hours in the fermentation and I don’t find it to be as spot on and I find it to power the fridge seldom and for a short period

Are my settings correct?
I have 80 Liters of beer inside a conical, and that conical is in a large fridge.
Beer sensor is inside a thermowell in the conical and the fridge temp is in a 0.5L water bottle inside the fridge
I just want the beer to stay at 19°c

Here are pictures of my settings

Any input much appreciated

brew2

It’s not uncommon to have to tweak settings a bit. 80L is somewhat more than what is assumed by the default settings.

For this, the PID values are used. Could you please go to the PID heater / cooler blocks (you can click on the frost/flame icons), and then in their actions menu open and screenshot their graphs?

These graphs will show how much P/I/D contributed to the total output.

1 Like

Thanks again for a quick reply
I guess you mean this graph/screen

I do not use a heater, but in the wizard I was forced to select output pins for a heater, but there is non in my system

I searched more for the graph you talked about and found it:

You can then disable the Ferment Heat PID block to deactivate the heater side of things. A heat/cool only wizard is on our backlog, but can’t give any ETA on that.

If you click on the three dots in the top right corner, you get the option to open the graph fullscreen.

Edit: you could start with increasing the Kp somewhat, to about -70. For this scenario, you’d want a P and D of ~0, with I solely being responsible for keeping temperature.

1 Like

I think you can indeed be much more aggressive with Kp, because of the large volume.

Try 200, with Ti at 12h and Td at 30m.

Thank you, I just entered those values

It stabilized now at 19°c, but I guess next night the yeast will go crazy causing the temperature to rise

So I’m happy to have changes those values before that

I’ll post results of the regulation after most of the fermentation has passed through

I guess that 200 is too much.
Is the most important figure of fine tuning on the graph “D”. That is getting it close to zero.
After I changed K to -200 it started swinging alot

Guess I should try maybe 100

P, I, and D all have equally important uses. In a stable situation like this, you’d want I to have a stable >0 value, and P/D to be fairly quiet.
In temperature steps (eg. you set setpoint to 15 degC) you expect to see P leading, and D adding dampening when the temperature gets close to setpoint.

Temperature looks good, but control is indeed somewhat swingy. May indeed try reducing Kp somewhat, and see where that ends up.