why build controller?

[MontuckyMadman]

So why do my controllers act like this?
pid ssr setup.
120v 1400watts and about 12amps each.
takes about 30 min to get to temp but i cant just set it to 180F or it will go to 220 before it stops delivering curent. I have to go up only 10-20 degrees at a time or it will just ramp out of control. Shouldnt it stop delivering curent when the thermocouple sense it reaches the target temp?
it seems these should work better.
the ittle red light on the display blinks as it delivers current. It eventually becomes increasingly more unpatient and thus goes solid red and delivers current continuously.
what wrong with my setup?

[vinman]

I'm no electrician or electrical engineer by any means. But when my controller acts funny I go directly to the thermocouples and see if they are working right. Your problem sounds like a TC problem to me.

I find things work best when the thermocouple is attached to my Alu without crossing itself/ twisting.

I also use Kapton tape to attach them. Read someplace that was the right stuff.

Also make sure wires are not loose in your TC.

Are your TC extension wires actually the right material? Copper wire won't do, need the right TC extensions inside the controller also.

[troublemaker]

So why do my controllers act like this?
pid ssr setup.
120v 1400watts and about 12amps each.
takes about 30 min to get to temp but i cant just set it to 180F or it will go to 220 before it stops delivering curent. I have to go up only 10-20 degrees at a time or it will just ramp out of control. Shouldnt it stop delivering curent when the thermocouple sense it reaches the target temp?
it seems these should work better.
the ittle red light on the display blinks as it delivers current. It eventually becomes increasingly more unpatient and thus goes solid red and delivers current continuously.
what wrong with my setup?

On the PID controllers I build, I run the thermocoupler all the to the controller. I also buy thermo in bulk and make my own whatever lenght I need, somewhere around 6 feet long. And be sure to use the auto tune function the first time you use whatever thermocoupler you have so the PID can "learn" the coupler. Once it is learned the temp might run past the set temp maybe 1-2 degrees then settle right down to set temp. BTW what PID do you have? Seems like they are all have about the same programming funtions.

[MontuckyMadman]

Thanks guys. Krp128 made them and he had the thermocouple wire and tuned them. I dont know how to tune them.
the tc knows the temp. It runs from the controller.
i dont know what kind they are i will check.

[krp8128]

Rob,

I did have the TC when I put this together, and the PID is set to the correct TC type (unless you have changed it).

Your problem is that you have not tuned the PID to your blanket/mold combination. The controller sees that it is at 70F, and needs to go up, so it delivers full power. Because you are not tuned to the characteristics of your setup, the control curve delivers way more power then is desired and the temperature overshoots.

I could go more into the theory behind PID control, but bottom line is you need to run an autotune on the setup and let the controller adjust a few variables.

Do you have the manual? I think I sent a link a while back...

[MontuckyMadman]

Hey k thanks, i see, i will try and dig up the email. Apreaciate it very much.
its the same type k, j, i forget tc you gave me, i didnt know it had to be tuned like a guitar or my shfance.

[MadRussian]

Had a chance to speak with distributor again and he suggested one more unit from Ranco. He said this one much easier to work with. Same specs 8A at 220 and probably little bit cheaper.

http://www.ebay.com/itm/251168246220?hlp=false