For all those who are about to say, Just buy an STC-1000 ...got it. I know that makes more sense than building it myself. I'm into this for the fun of it.
I'm working on building up my recirculating mash BIAB system. The basic setup is a 10 gallon pot with a recirculating pump. The heat source is a hot plate under the kettle.
For the temp controller I had the idea to use this https://learn.adafruit.com/sous-vide-powered-by-arduino-the-sous-viduino/sous-vide
I've got the hardware up and running, but I find it does not autotune itself very well. It is designed for a much smaller water volume that swings much more than my mash. The biggest problem is that it overshoots temp by as much as 10 degrees when heating up. It then will take a few hours to finally settle back to set point. What seems to be happening is after it overshoots it's trying to slowly land it back at setpoint so it doesn't undershoot. It keeps applying heat to slow down the cooling rate. I'm not sure why it can't learn the system better and compensate.
So, here's my question. Does anybody understand PID systems well enough to tell me how to manually set the Ki, Kp, and Kd to better recognize my setup? I think what I want to do is have it react much more instantaneously. I've tried researching and tweaking things, but can't seem to figure out the abstract nature of the settings.
One piece of advice I found in my research is that for something like this, PID is probably just complicating things. Because the thermal mass of the water acts as a stabilizer, a simple cut off controller would do a better job. I could write a custom program to do that, but I'd rather use this program as a base since it has a pretty workable user interface.
Any help would be greatly appreciated.
For those more interested, here is the code that runs the system.
https://learn.adafruit.com/sous-vide-powered-by-arduino-the-sous-viduino/the-whole-enchilada
Here is an alternate version that lets you set it to Fahrenheit. I've been using this version of the program.
https://github.com/bradydoll/Sous-Videno
I was able to put the pieces together for much less. I bought the display control board and arduino uno from Adafruit. The rest I sourced from ebay and amazon for significantly less. If and when I get this thing working better I'll do a build thread for those interested.
I'm working on building up my recirculating mash BIAB system. The basic setup is a 10 gallon pot with a recirculating pump. The heat source is a hot plate under the kettle.
For the temp controller I had the idea to use this https://learn.adafruit.com/sous-vide-powered-by-arduino-the-sous-viduino/sous-vide
I've got the hardware up and running, but I find it does not autotune itself very well. It is designed for a much smaller water volume that swings much more than my mash. The biggest problem is that it overshoots temp by as much as 10 degrees when heating up. It then will take a few hours to finally settle back to set point. What seems to be happening is after it overshoots it's trying to slowly land it back at setpoint so it doesn't undershoot. It keeps applying heat to slow down the cooling rate. I'm not sure why it can't learn the system better and compensate.
So, here's my question. Does anybody understand PID systems well enough to tell me how to manually set the Ki, Kp, and Kd to better recognize my setup? I think what I want to do is have it react much more instantaneously. I've tried researching and tweaking things, but can't seem to figure out the abstract nature of the settings.
One piece of advice I found in my research is that for something like this, PID is probably just complicating things. Because the thermal mass of the water acts as a stabilizer, a simple cut off controller would do a better job. I could write a custom program to do that, but I'd rather use this program as a base since it has a pretty workable user interface.
Any help would be greatly appreciated.
For those more interested, here is the code that runs the system.
https://learn.adafruit.com/sous-vide-powered-by-arduino-the-sous-viduino/the-whole-enchilada
Here is an alternate version that lets you set it to Fahrenheit. I've been using this version of the program.
https://github.com/bradydoll/Sous-Videno
I was able to put the pieces together for much less. I bought the display control board and arduino uno from Adafruit. The rest I sourced from ebay and amazon for significantly less. If and when I get this thing working better I'll do a build thread for those interested.
