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JDL612 PT100, PV below SV

Posted: Sat Feb 02, 2013 6:04 pm
by BillM49301
I ran through a Auto Tune cycle (SV=100 degree F) and the controller is reading SV=100 and PV=99, a little low. Using a Slow Cooker on High with approx 6 quarts water. The Out (SSR) is pulsing at about 2 to 3 seconds. Watching over an hour and the PV only reached 100 very briefly then went back to 99. Not bad, but should be better? :(

Re: JDL612 PT100, PV below SV

Posted: Tue Feb 05, 2013 9:53 am
by richiem
Nope, working fine. This is just a digital effect of the analog-digital converter (ADC) and the display. If you use a Pt100 RTD and the Pt10.0 sensor setting, you will see that the error is much smaller, essentially negligible.

Re: JDL612 PT100, PV below SV

Posted: Sun Feb 10, 2013 11:10 am
by BillM49301
richiem wrote:Nope, working fine. This is just a digital effect of the analog-digital converter (ADC) and the display. If you use a Pt100 RTD and the Pt10.0 sensor setting, you will see that the error is much smaller, essentially negligible.
Thanks for the tip. I did change it to PT 10.0 and it now looks better. I'm going to graph the time temp relationship to see is everything else is OK.
I have been checking the internet and lots of posts on how to tune a PID but nothing on the JLD612.

Re: JDL612 PT100, PV below SV

Posted: Mon Feb 11, 2013 1:03 pm
by richiem
Many people, including myself, have found the auto-tuning function in the JLD612 to work quite well. Its setting could provide you with a good baseline for altering control parameters.