PID Controller with switch heat and variable fan ok for PID control?


I was hoping to use a switch heat matt (on/off so no float) and a variable extractor fan to lower heat. It says in the intrusion’s that to use PID you must have at least one float available (which is the fan) so instead of only having the fan for PID control would it be ok to add heat for when the temp drops to much?

It would not be as good as a variable temp but this is what I have at the moment. I am looking to keep my temp a stable 24-25 degrees.


did you have a look for SLOW_PWM output? PWM (pulse wide modulation) only switches on/off but still can controll temp by changing switching ratio…

I was intending on using a seedling mat with either just on/off 60w or a different one which does 3 power settings, Off - Low - Med - High (105w being max wattage) which I guess gives it a small float so that might help better?

The mats take up to 15m to heat fully so would the PID controller learn from that while doing the passes during Auto Config?

Hi i am just learning slow Pid controller in combination with pid thermostat. The autoture works fine. But it need about 4 cycles (up and down) to set up. So be patient

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Hi I mean, does it matter that the mat take 15 min to reach full heat? It’s not instant on or graded so I was wondering if the PID controller recognises this and if its to cold it turns on sooner etc. Also, when it starts ti get close to the correct temp will it turn off early due to it staying heated longer than convection fans (instant heat)?

Hi, PID means that d part should handle the fast reactions, the i part is dor long term precision. The autotune function recognizes this time functions…

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Perfect, so the heater would just switch on and off a required to maintain a temp?