PID Help Please!!

[500MAG]

I built a PID this week and everything works well. The only problem is I must not be programming it right. I set the target temp but when I turned the pot on it breezed right past the target temp. I am including the link to the directions, maybe someone is using the same one and can give advice.
Thanks :groner:

http://www.happybuyerstore.com/manual/new2006power.pdf

[snuffy]

That is normal. After it "learns the TC",(thermocouple), it will overshoot less each time you turn it on. Even after 2 years, mine still overshoots the set temp by around 35 degrees. BUT it quickly compensates, after going below the set temp before stabilizing +- 1 degree of set temp. I have 2 pots and 2 sizers I run off of my PID. It has to re-learn each different probe before it can stabilize at the set temp.

If you are using it on only one pot, you can let it self program, "auto tune" so it learns the TC better.

BTW, what did that cost? I looked at the main page of that website, I saw no price for that PID>??

[Walter Laich]

Looks like it's an auction item with no set price.

[HATCH]

do the auto tune feature.
page 5 - 6.1 and 6.2
I have the same PID and it works fine.
It takes a few mins to get it working right but then its fine.
keep in mind that on my lee pot, if I add lead it will drop temp dramatically and take a few mins to get back up to temp.
I cast some last night with my MPmold and I turned to temp up to 800 degrees just but hitting the arrows.

[500MAG]

Thanks guys. Hatch I'm so happy that someone else has the same one and it works. The price was $27 including shipping.

[popper]

That's normal. A PID is a temp controller that tries to get to set point temp faster by temporarily overheating. It will always overshoot, just less when it 'learns'.

[Casting Timmy]

I used to work for a heater manufacturer, I only liked the controllers that autotuned. Continued overshooting can also be affected by thermocouple placement and how much of a heater that you have. The farther away the TC is from the heater you can just naturally get some overshoot.

[fred2892]

I am using the same PID unit and at a set temperature of 750 it overshoots to 770 and does not kick back in until down at 725. This is after using the autotune feature.
Also when coming back up to temperature the output is flashing on/off regularly, similar to when autotuning. Is this normal?
I have not changed the factory settings for the P, I and D parameters. These are P=5, I=100 and D=20. Do I need to change these parameters to improve performance?
I have built it using an old computer psu and have retained the 12v dc case fans. Can I wire one of these fans into the pid using terminals 13 and 14 as is shown in the alarm example in figure 10 in the instructions? (OP link, post #1 above)

Thanks for any help.
Fred

[Frozone]

......These are P=5, I=100 and D=20. Do I need to change these parameters to improve performance?........

Very likely.

I'm not sure about the Unit you have - but Most simple PIDs have a relay as the alarm output control.
No power out is available, it's just a simple SPST switch.

[fred2892]

Having just re read the instructions I see that you are spot on and it is just a switch and the fan would need an external 12v dc supply. I also read where it doesn't matter what the P, I and D parameters are as the autotune feature sets these automatically. Thanks.

[Frozone]

...... it doesn't matter what the P, I and D parameters are as the autotune feature sets these automatically.....
That is correct - IF you use the autotune function - you never said you had.

[fred2892]

Yes I did. First paragraph, last sentence.

[500MAG]

Is your thermocouple wired in directly or do you have the plugin?

[Frozone]

Yes I did. First paragraph, last sentence.

Then the factory settings would already be changed. and wouldn't be P=5, I=100 and D=20 would they.

To answer your other question - yes, the Output lite will flash as the unit operates.