Simple Time / ON/OFF profile?

[DystopiaNow]

Hi, I'm using your code with a toaster oven that uses four ceramic heaters, about 1500W, and I find nearly impossible to have a calibrated PID (tried most of the algorithms for auto tune). Using PID, the oven takes more than 6 minutes to reach 150º, and approx 12' to complete the reflow process. However, turning the oven ON at full power up to 120º and then shutting it down when it reaches 150º and then ON again up to 205º gives me about 7 minutes and a profile similar to what I need. Will it be some simple Time/Temperature/ON-OFF profile option in a future release?

[foxis]

Hi,

I think the problem lies with the calibration. For some reason sometimes the automatically generated coefficients are too small. Therefore for best results, it is necessary to tune them by hand.

As for the ON/OFF profile - it is possible to achieve the same effect using custom PID values. E.g. you may want to set I and D terms to 0 while P to a reasonably high value.

Perhaps you could share the PID values as well as the temperature graph for both using autotuned PID and turning the oven ON using the method described above?

[DystopiaNow]

These are the values I got using Ciancone Marlin PID Autotunning: 0.021435, 0.000135, 1.843517
With Overshoot Autottuning: 0.025984, 0.000075, 6.027832.

The calibration processs curve looks like this:

This is a "reflow" profile that lasted 11 minutes (changing the slopes of the Non lead free profile). With No Overshoot PID.

And this is what I've got with Ciancone Marlin PID and some adjustments with slopes=0:

And finally a picture of the oven (I suspect that the heaters are too "slow" since they are ceramic type ones)

So, playing with turning it ON and OFF manually I can achieve 7 minutes.

Thanks in advance.

[foxis]

The autotune temperature profile actually looks correct. However, I can notice that the heatup time is a bit too slow...
And the Proportional value seems a bit too low... You can try to tune the P value a bit. Try 10x the original value and see how it all improves.
This might result in slight overshoot, but that still should be within tolerances (check the datasheets of your parts though).