PID Timer Controlled Tempering (Toaster) Oven WIP

Ken H> said:
The MyPin controller has an alarm contact on terminals 5&6 you can use to to alarm high temps.
Click to expand...

ok 5and 6 on the mypin but can I use the timer to operate the same alarm simultaneously or will I need and independent alarm for each unit? I'd like to just have one if I can.

Btw thank you both for all the help.
 
Got some work done on the oven while waiting one the rest of the electronics. Removed all of the unwanted wiring and controls. Cut out some metal to clear room for the new controls and cut a priece of metal for the controls to mount to.





 
Marc, Not exactly sure what you mean to use the alarm for - BUT for sure you don't want the alarm turning the heating elements off. That would mess up the algorithm in the MyPin for controlling heat. I think the ONLY thing you might wish the alarm do is trigger a buzzer/light. No shutdown involved.
 
Ken H> said:
Marc, Not exactly sure what you mean to use the alarm for - BUT for sure you don't want the alarm turning the heating elements off. That would mess up the algorithm in the MyPin for controlling heat. I think the ONLY thing you might wish the alarm do is trigger a buzzer/light. No shutdown involved.
Click to expand...

You're right Ken. I don't want the mypin to shut down, but I would like it to alarm is it overshoots by X number of degrees. I do want the alarm to sound and shut off with the timer however.
 
Last edited:
Just checked my tracking numbers, and the last part is in the mail box.... Looks like I know what I'm doing the next night or two.... :D
 
When you are all done, please post a schematic and list of parts. I would like to convert my oven over too! I have the PID, SSR, Thermo couple, etc but I'm an electrical moron but have a buddy who is pretty good with it. I appreciate all your hard work!!
 
The schematic and info for how to convert a toaster oven is already in the PID sticky. ( In the Good Info Sticky)

Marc's is a tad different, as he gutted the old oven controls, but the basic control is the same.
 
You're probably going to want some insulation between your electronics and the body of the toaster. Electronics really don't like to be hot...


Sent from my iPhone using Tapatalk
 
A.McPherson said:
You're probably going to want some insulation between your electronics and the body of the toaster. Electronics really don't like to be hot...


Sent from my iPhone using Tapatalk
Click to expand...

Yeah, that's coming, just need to get it wired up first. And waiting on the mail man to bring it. I'm using a product called Lava Mat Thermal Barrier. It's very thin, no problems with fiber dust, and is highly efficient at reflecting heat. It will be very easy to wrap the internal oven chamber. I will probably even use a piece to cover the door to help keep more heat in.
 
I'm going to make updates maybe tomorrow. Wiring diagram has to be updated as it is off quite a bit and I've added some switches for bypassing the alarm and timers for preheat. Most of the diagram is correct but the timer to ssr is off and a couple other things. Learned a lot today on how these units work. Takes about 15 mins to get up to temp. So far it only swings + - 8* from the set point. Thinking I can get it closer with the auto tune and better insulation and more thermal mass. The auto tune is definitely better turned on than off.
 
Well it looks like the most efficient way to use this is to let it pre heat for 15 mins after it reaches temp. After 15 mins at temp it only swings + - .8 degrees over 2 hrs at the second current test. Not bad if I don't say. Thinking I'll be getting much better temperings.
 
Here is the updated schematic. I will update all other comments on this thread with the updated one so people don't get confused which one is correct. I added a few features I'll list below.

  1. Timer bypass switch for preheating oven. This allows the unit to run on the temp control PID only. I actually have an on|off|on switch instead of the on|on switch drawn. This allows both PID and timer to be powered up but disabling the heating elements from heating if I need time to program the settings in for various heating needs.
  2. Alarm on/off switch. While preheating oven if timer is bypassed the alarm will still sound if the timer runs out, this switch disables the alarm completely. I have also found that is is good to allow the oven to preheat for a min of 20 mins at temp. after 20 at temp, the temp swing stabilizes to within about + - .8* During the initial heat, it overshoots by 12* twice before it levels out, this also allows the alarm to not sound during that preheat time.
  3. 12v DC cooling fan run off a class 2 transformer. Even though I used decent insulation, it is a very confined space close to hot temperatures this keeps the SSR very cool to the tough even after a straight 4 hour heating test at 400*. It also keeps the PID and timer controls cool. I'm sure this will help prolong their life.



 
Updated picture of the control panel with switches for disabling the alarm and bypassing the timer and/or the elements.






You can see the thermocouple going into the 3/8" steel plate used for thermal mass. This sure does help it maintain temp.

 
You must log in or register to reply here.
Back
Top