don't buy cheap crap

doughboyshredder · Post by **doughboyshredder** » Sun Jan 09, 2011 7:20 pm

I needed a new pid and I am low on funds so I ordered the cheapest one I could find.

Not surprisingly it is reading 20 degrees celsius higher than my other pid that I know from experience is spot on.

So, in an effort to save 80 dollars I actually wasted another 50. RAD!

COsurfer · Post by **COsurfer** » Sun Jan 09, 2011 8:24 pm

Bummer man! If it makes you feel any better I have 2 "Love" controllers and one read 120 degrees and the other read 350 degrees on my last press. This is after messing with the TC's for about 3 hours. The good news, the board came out fine! What PID did you buy? R U going to buy another?

doughboyshredder · Post by **doughboyshredder** » Sun Jan 09, 2011 9:22 pm

JLD 612

It's made by some chinese OEM.

32.50

Cheap is never a good deal, and I know that.

I think I am going to run with one pid for a while. Probably preheat the press so the cat track doesn't rob a bunch of heat from the top blanket, and run the pid off a thermocouple on the bottom blanket.

The PID that I should have bought, which is the one that I have been using is 150 dollars. First off I am going to try and get lightobject.com to send me a replacement of the cheapy, but we'll see.

twizzstyle · Post by **twizzstyle** » Sun Jan 09, 2011 9:22 pm

Do you have it set to the correct thermocouple type?

I have a cheapo-chinese-ebay PID controller and it suits me fine, but it seems like you could change what kind of thermocouple you used with it?

(as I'm typing this I'm second guessing myself...I better see if I still have the instructions or if I'm just posting bullshit right now)

doughboyshredder · Post by **doughboyshredder** » Sun Jan 09, 2011 9:23 pm

twizzstyle wrote:Do you have it set to the correct thermocouple type?

yep, and the polarity is right also.
I messed around with the digital filters also. Had both pid thermocouples in the same spot on the blanket, and the cheapy consistently read 15-20 degrees celsius high.

leboeuf · Post by **leboeuf** » Sun Jan 09, 2011 10:00 pm

If you're looking for a replacement, an auber instruments pid can be had for cheap... They work extremely well and many can take rtd temp sensors if you want to push your accuracy.

www.auberins.com

SHIF · Post by **SHIF** » Mon Jan 10, 2011 9:25 am

leboeuf wrote:If you're looking for a replacement, an auber instruments pid can be had for cheap... They work extremely well and many can take rtd temp sensors if you want to push your accuracy.

www.auberins.com

These are among the many found on eBay, search "kiln controller".
I have one that cost less than forty bucks and has performed well for over three years. I often check it against my Fluke thermometer and it is close enough. However I may "upgrade" to a unit that allows programmed "ramp and soak" functions which will add another level of consistency to ski building.

-S

chrismp · Post by **chrismp** » Mon Jan 10, 2011 9:25 am

doughboyshredder wrote:
twizzstyle wrote:consistently read 15-20 degrees celsius high.
well, if the readings are consistent...

knightsofnii · Post by **knightsofnii** » Mon Jan 10, 2011 12:52 pm

damn, my controller was like 750 bucks, and its asstacular,
where do i get this so called good $150 controller?

Brazen · Post by **Brazen** » Mon Jan 10, 2011 1:50 pm

Hey Knights,

Omega has a cn7833 for around 100 bucks...I thought these were a great deal for what they are and, so far so good.

doughboyshredder · Post by **doughboyshredder** » Mon Jan 10, 2011 6:19 pm

knightsofnii wrote:damn, my controller was like 750 bucks, and its asstacular,
where do i get this so called good $150 controller?

I'm not talking the entire control box, just the PID. I got the good ones from instrumart.

Chrismp, I was thinking the same thing. Running another test right now.

vinman · Post by **vinman** » Mon Jan 10, 2011 10:21 pm

Are you sure the initial parameters are correct and Did you run the auto tune for the PID? Are you sure the other PID is working correctly?

doughboyshredder · Post by **doughboyshredder** » Tue Jan 11, 2011 8:34 am

I did not run the auto tune or tweak the parameters.
It was my understanding (which may be wrong), that the parameters and auto tune had nothing to do with the reading of the thermocouple and only had an effect on the output of the pid. Is this incorrect?

Pretty much positive the other PID is good since I have had two of those and they were both exact to each other for a couple years.

I suppose it is possible that they were both reading low that entire time, but I highly doubt it.

vinman · Post by **vinman** » Tue Jan 11, 2011 10:27 am

Not sure what the initial parameters do really but maybe try running the auto tune and see what happens.

I'll be interested to see what you come up with. I have these PIDs but I'm not done with my control box yet.

Maybe try the lightobject forums for more info as well.

feldybikes · Post by **feldybikes** » Tue Jan 11, 2011 3:42 pm

Doughboy,

Unless you got a totally jacked thermometer, you should be correct that the TC reading has nothing to do with the tuning parameters. All those do is tell the power output when to turn on and off.

I (unfortunately) know a lot more about PID and temperature control than I do ski building.

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don't buy cheap crap

don't buy cheap crap