System to Regulate Temperature

[p.f.sanford]

Hello,


I am trying to build a system using a microchip (pic16f84) to sense the temperature in a vacuform machine and control current to the heating element to keep it a certain temperature. The vacuform plugs into the outlet 120 VAC and the heating element draws about 15 amps, it should be able to get up to 600 degrees. I would really appreciate any help on this

I am having trouble figuring out how to control the ac circuit with the microchip. I found a solid state relay that seems to be adequate, but saw that it only had 100,000 cycle lifetime. That would be just fine, but I was considering using it as an way to control the current. At 50HZ it would not last long. Is their any better way to engage/disengage the ac current?

I have also been trying to find a better way to control the current. Is their some kind of variable rheostat that can handle the ac current and be controlled electronically?

Thanks,
Pat Sanford

 

[dian]

Hello,


I am trying to build a system using a microchip (pic16f84) to sense the temperature in a vacuform machine and control current to the heating element to keep it a certain temperature. The vacuform plugs into the outlet 120 VAC and the heating element draws about 15 amps, it should be able to get up to 600 degrees. I would really appreciate any help on this

I am having trouble figuring out how to control the ac circuit with the microchip. I found a solid state relay that seems to be adequate, but saw that it only had 100,000 cycle lifetime. That would be just fine, but I was considering using it as an way to control the current. At 50HZ it would not last long. Is their any better way to engage/disengage the ac current?

I have also been trying to find a better way to control the current. Is their some kind of variable rheostat that can handle the ac current and be controlled electronically?

Thanks,
Pat Sanford

Hello Pat,
I suggest you to use Triac instead Solis State Relay (SSR) to control the power from 120Vac.

try this link for sample
The TRIAC : THYRISTORS

regards
Dian