Oven working but need a little assistance

[snowhoundxp]

My oven is operational but I have one issue. I have a TET612 controller. I set the temperature and push the auto tune button in but it does not stop flashing. I turn the switch from the PID to the contactor to send the juice to the coil and it works. The only thing is when the auto tune light stops flashing, it quits working and then the contactor starts clicking. When that happens, I cut the juice between them to reset the auto tune. It's all right for a while. I've held the auto tune in until it quits flashing and it does the same thing. Both ways it does the same thing. Normally it will take 3 or 4 sets to run a cycle. Any idea what I'm doing wrong and why I have to keep resetting the PID?

Thanks for any assistance.

[ed_denu]

Originally Posted by snowhoundxp

My oven is operational but I have one issue. I have a TET612 controller. I set the temperature and push the auto tune button in but it does not stop flashing. I turn the switch from the PID to the contactor to send the juice to the coil and it works. What switch is this? The contactor should be hard wired to the pid. What terminals are you using from the pid to the contactor? The only thing is when the auto tune light stops flashing, it quits working and then the contactor starts clicking. The contactor should start clicking as the set temperature is reached, that's a normal function for the pid/contactor. When that happens, I cut the juice between them to reset the auto tune. It's all right for a while. I've held the auto tune in until it quits flashing and it does the same thing. Both ways it does the same thing. Normally it will take 3 or 4 sets to run a cycle. Any idea what I'm doing wrong and why I have to keep resetting the PID?

Thanks for any assistance.

See comments in red.

How is the pid/contactor wired? What schematic was used.

If the auto-tune completes, why are you running it multiple times?

[CarWiz]

Everything you've mentioned sounds normal to me. While the PID is in auto-tune (a-t) mode, the light will blink. When the light stops blinking, the auto-tune parameters have been stored and you're ready to start baking parts. It's normal for the oven to go over-temp during a-t so NEVER use auto-tune with coated parts in the oven. If you cancel the a-t, no new parameters will be stored. Auto-tune is used by the PID to learn how your oven reacts to heating cycles over a period of time. You should let the PID complete the a-t cycle before trying to cure parts.

[CarWiz]

Forgot to mention: The only time you should run auto-tune again is if you make changes to the oven or change the initialization parameters at 0089.

[snowhoundxp]

Thanks for the information. The PID and contactor are hard wired together. I just put a switch in-between so I could shut the oven off and still be able to program the PID. I figured out that if my oven is set at 380 degrees with the PID, a standard oven thermometer that I placed inside the oven will show 400 degrees. Not sure which is accurate. When the oven got to 370 degrees the contactor started clicking and continued to click and narrowed it into 380 degrees. The oven stayed at 380 but the contactor continued to click every several seconds and woudn't stop. So you're saying this is normal? Thanks.

[ed_denu]

Yes, absolutely normal. The relay contacts in the contactor will remain closed until the set temperature approaches. As the set temperature is reached, or near, the pid will begin cycling the contactor on/off to settle in at the set temperature. You might want to set parameter 'OT' to a value between 5-15 as with a contactor you don't want the electro-mechanical relay to cycle too frequently.

The difference in temperatures you are seeing could be due to many things, including placement of the tc. There is a temperature offset parameter(PSb) you can adjust if you feel the tc is reporting incorrectly