JLD612 and PT100 RTD

gmc8757
Posts: 3
Joined: Wed Mar 04, 2015 6:52 pm

JLD612 and PT100 RTD

Postby gmc8757 » Wed Mar 04, 2015 6:55 pm

Hello, I ordered these two items, I got them set up fairly easy but the temperature reading seems to be quite a bit higher than it should be. I tested it by comparing its reading to a few different dial thermometers. The dial thermometers were consistent but the JLD612 and PT100 were not.

Any suggestions on how to get it to read correctly?
Thank you

Tech_Marco
Posts: 4306
Joined: Mon Jun 15, 2009 3:00 pm

Re: JLD612 and PT100 RTD

Postby Tech_Marco » Fri Mar 06, 2015 11:38 am

There is offset you can fine tuned it. Check with the manual


Marco

gmc8757
Posts: 3
Joined: Wed Mar 04, 2015 6:52 pm

Re: JLD612 and PT100 RTD

Postby gmc8757 » Fri Mar 06, 2015 12:57 pm

Any idea how to do that?
I'm not getting it from this manual.
http://mythopoeic.org/misc-files/JLD612_Manual.pdf

richiem
Posts: 270
Joined: Mon Jan 03, 2011 3:47 pm
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Re: JLD612 and PT100 RTD

Postby richiem » Sun Mar 08, 2015 10:32 pm

How far off does it seem to be? Are we talking a degree or two, or tens?

gmc8757
Posts: 3
Joined: Wed Mar 04, 2015 6:52 pm

Re: JLD612 and PT100 RTD

Postby gmc8757 » Mon Mar 09, 2015 4:08 am

At 150f it was reading about 175
At 55f it reads about 70
So quite a bit

richiem
Posts: 270
Joined: Mon Jan 03, 2011 3:47 pm
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Re: JLD612 and PT100 RTD

Postby richiem » Tue Mar 10, 2015 11:06 am

Yep, that's a lot -- I suspect that either the Pt100 RTD probe is bad, or the JLD612 has a problem. Talk to Marco.

If you have a digital ohmeter or a good quality DMM, stick the probe into a slurry of crushed ice and water, and measure the resistance between one red wire and the blue wire -- it should be very close to 100 ohms. if it is off by quite a bit, say 10 percent, then it needs to be replaced. You can check the other end of the scale by immersing it in rapidly boiling water, if you are near sea level (<1000' above) -- the nominal value should be 138.5 ohms; again an error of 10% or more is an indicator of a bad probe. The resistance of the red and blue wires should be a small part of the total (<0.5%), so it can be ignored.


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