I realise you get a lot of these questions but I haven’t been able to glean much direction from other posts.
I’m attempting to configure the PID settings for my BIAB setup. It’s a 70L pot with a 5500W element and recirculating pump. I wrote a post about my setup a couple of years back:
I did a water test last night with 35L of water (I aim for 30L into my fermenter). The temperature control does not appear as stable as I would have hoped. These are the PID settings (default from wizard):
I tried a number of different temperatures and tried to leave it for 15-30 minutes at each temperature to stabilise. Here’s a summary graph (note there was a loss of data from 21:18 to 21:45, as my Raspberry Pi dropped off the network for some reason):
Zoomed in when set to 70°C:
It looks like the Differential portion seems to be contributing quite a lot. Also I suspect Kp is too high?
I also tried boiling. Boil was reached when the probe was measuring 98°C. From what I can see the controller didn’t detect boil so the “minimum output when boiling” was never reached. Is this an indication that my probe needs calibrating? Can the “Boil Temperature Setting” be -ve?
I’ve also attached a CSV export from the Session Log:
graph-Mash Graph-brewpi_p1_mash-downsample_1m.csv (51.8 KB)
As a side note the session log appears to be at a down-sampled rate compared with the live data. Is this adjustable?
I’m also in the process of configuring my new Fermentation chamber. I’ll see how it goes but may also be after some tuning advice for that.
Thanks in advance!