2 Stage Control

[rcrabb22]

Does this state machine seem reasonable for 2 stage control of a fermentation chamber?

Two Stage Ctl
• State 0: Temp +/- Rest. Exit0 timer0 <=0 , initialize timer0 = 10:00 min, goto State 1
• State 1: Hold Temp; Exit0: temp0 > = 68F goto State 2. Exit1: temp <=66 goto State 3
• State 2: Cool; Assert out0, cool source; exit0 temp0 <= 67F goto State 0
• State 3 Heat; Assert out1, heat source; exit0 temp0 >=67F goto State 0

State 0 is for temperature over/under shoot. The heating or cooling source might give off residual temperature influence after shut down so I was giving a rest period for temperatures to equalize and also for compressor rest cycle for cooling source. If the process was restarted after a power hit, I would also want a compressor rest period on process restart

State 1 will use 2 exit conditions to call for either heat or cooling as needed.

The dead zone temperature range (range between heat and cooling) would need to be adjusted for actual performance of the fermentation chamber and temperature probe stability.

Comments?

[ECC]

Yes, that looks great.

[NakedDave]

Thanks for posting this, it would have taken me a long time to figure it out on my own.

[mrlisk]

Thanks for that! I'll adapt this to work with my kegerator. I like your temperature rest idea for state 0