ECC Forum

The Top Graph is PID Controlled, The second one is for Hysteresis Controlled. I used the default PID settings and changed the Hysteresis to 1 degree. It is the same Out.
Graphs are same scale.

It looks like the Hysteresis Controlled gives a better graph. I thought PID would be a better choice for an electric element. This was a 2 sec trace for about 20 minutes (I pasted the graphs in Paint {and had to shrink the file to fit the Blog restriction} together to get a longer look in the attachment). Any suggestions for adjusting the PID setting as I know nothing about them. The Hysteresis Controlled is fine and that is what I used on my last brew session, and when I start to use on a fermenter I will use Hysteresis for that.

Just trying to wrap my head around PIDs.

Not sure if you got an answer to this, I know its been awhile but I have some experience with this at work.

I work for an Airline overhauling and testing of Fuel Controls for Engines. We run them on large test stands with multiple inputs, ie fuel flow, air temp, air pressure , back pressure curves etc. For that we use PID almost exclusively because of its ability to control many inputs with its mathematical function. Basically its a Calculus Derivative Formula.

Hysterisis is a much simpler controller and would probably work better in our situations as we are only basically controlling a fixed temp set point, as we dont have to really worry about controlling multiple inputs and variables.

those graphs look funny, are you running a pump only part of the time and the flat part is when the pump is not running? my mash graph with pid is a flat line...

Tolerance and scale of graph may be fooling you. These are very small fluctuations magnitude of .1 degree mostly.