
Originally Posted by
joeri
at 100°C I have 11 kOhm; at 150°C I have 3 kOhm; at 260°C I have 500Ohm. I use a current source which drives a small current through the NTC, then I amplify the voltage over the NTC with a opamp and bring it into the analog pic input. So far, so good.
The oven is a samsung with 1500W. I added two heat resistors from a waffle machine (another 1000W), so total of 2,5KW.
This boosts quite fast. Also, I have a fan to equalize the temp inside the oven. The complete oven is packed in rockwool.
But my problem is the PID. Any experience on how to work with negative errors (overshoot)?
The calculate PID values are:
gain= 10
I= 0,04
D = 100
So it seems I have a PD controller. Due to the slow process, that might be ok. Or not?
Bookmarks