PID SET620 help

[damfast]

Ive been browsing this forum for a couple years now and have just finished my second oven build. I am having trouble programming my pid..I have tried the instructions for the 612 but im lost...can anyone put it simpler for me. I put 400 degrees in and it just keeps climbing on the auto setting and ive tried to set paramiters but no luck. please help and this forum is a great help..thanks todd

[ed_denu]

Todd, I'm not real clear on what problems you are encountering. Is the auto tuning function not working properly? Is the temperature climbing beyond the 400 degree setting during auto tuning? If it is this is somewhat normal as long as it doesn't go to far over. Please be more specific and note what you are observing and someone should be able to help you. Ed

[JTW37]

Yep, auto tune shouldn't go that high to adjust itself. If you messed with the PID settings, put it back to auto tune. It will go up above 400, once you tell it 400, but only around 25 -30 maybe 50 degrees.

[damfast]

yeah i had it set at 375 and it went on up to 420 or so and then i shut it down..if i understand it right it should be cycling my ssr and shutting down the burners,.is that true? Will it get better...arent they supposed to kinda train themselves to keep it closer to the target temp because 50 degrees is to big of a diff for powder. thanks for the help

[ed_denu]

Are you observing this during auto tuning? If so auto tuning will go somewhat over the set temperature as the pid is learning how quickly the oven and elements react to the on/off cycles.

If the ssr isn't cycling on and off at all once it reaches and surpasses the set temperature, then it sounds like you have something wired wrong or the ssr has malfunctioned with the contacts closed(do you have a good heat sink on the ssr?). Watch the pid when it approaches and exceeds the set temperature. The output light will be lit when the pid is calling for heat thru the elements, and off when it is not. If the output light is off and the elements are still on, then you have a wiring or ssr failure problem. Some ssr's also have an led light which lights when it is energized. Watch this also.

[damfast]

i do have a good heat and i will watch for those things thank you for the imput and I will let ya know what happens

[damfast]

ok guys heres the scoop...my box is mounted to the side of the oven and it got so hot that it melted the ssr...the oven still works so the ssr didnt blow but it melted the outside. Im thinking im gonna move the box off the oven...any ideas

[ed_denu]

Are you sure that's the problem. If the oven walls are insulated there shouldn't be that much heat radiating through. It's very possible that you need a better heatsink on the ssr. I recently add a computer heatsink and fan(12V) to my ssr.

If you still feel the control box is getting to hot you might add some spacers between the box and the oven wall. If you want to go one step further, then you could insulate between the two.

[PhredAre]

Northern Tool sells a muffin fan,( mini box fan), that sells for $7.99 and operates on 115volt. Moves 100cfm, could help to cool the NEW SSR that you most likely will be buying. Fred

[damfast]

thanks for the imput guys i already have spacers but it still gets pretty hot...i will need a new ssr so that sucks but i was theinking about using some wood as an insulator between the oven and the box.