JLD612 passes setpoint.

[clay]

I have a JLD612 being used to control an electric heater application. I’m using a K thermocouple and a SSR to control the heating element. All the connections are as shown in the manual on figure 7.

1,2 – ac power in
6,7 – DC side of SSR
9,10 – thermocouple

The current settings are:
0089
INTy = K
Outy = 2
Hy = 3
PSB = 0
Rd = 0
CorF = 1

I also tried with the default setting for these originally.
0036
P=5
I=29
D=20
SouF=.2
Ot=2
Filt=0

0001
SU=1120
AH1=0800
AL1=0900
AH2=0800
AL2=0900

Originally I connected to my heating application and set SU to 2250 (I’m assuming the decimal point is implied and that’s 225.0 degrees?) and ran the system. The temperature matched the temperature on my case thermometer (close any way) but the temp when up and up past 225 until the case temp limit started cutting off the heater at 250. At that point I tried the auto tune. It ran 24 hour and spent the whole time after the first few minutes at the 250 limit and then I aborted it.

At this point I removed the controller and hooked an incandescing light to the SSR and taped the thermocouple to the bulb. Set the temp to 112 degrees and turned on the light. The temp climbed and as it approached 109, the light tuned off for a few seconds then back on. This repeated three time as it approached 112 but once it passed 112, the light just remained on till the tape melted and I shut off the light manually.

At this point I started tinkering with the PID setting to get faster response (the light heats up about a degree per second…) but I never found setting that changed the behavior. I thought surely I have a bad PID… but I get a second one (also new) from a friend who is doing the same project, and his behaved exactly the same way.

Any ideas what I’m doing wrong?

The second photo show it just sitting on my desk. RD =0 and temp is 75 set point is 71 and HY is 3 and it’s still got the SSR relay on…

[Tech_Marco]

Try using "Auto Tune" for collecting P.I.D info.
Set up the system in 'closed loop' form (heater must be connected and powered) before enable AT.
It may take hrs or up to 24hrs to complete the AT process

Marco

[clay]

Is the case in the second photo where the current temp is > the set point by more than hysteresis and the out is still on normal when RD = 0?
The units stayed that way all afternoon. How much overshoot should I see during auto tune? I set up the test where the thermocouple is taped
to the light bulb and the bulb is switched by the SSR. With the set point set to 0830 (I'm thinking this is 83.0 degrees) and a current temp of 72
I started auto tune. It’s been running 15 minutes and the current temp is now 118. Well past the set point. And the SSR is still on.

[richiem]

Hi Clay -- with K thermocouple, I don't believe the decimal point is not implied -- so for 225 deg you want 0225 as the set point. Same for the other settings.

[clay]

Thanks. That was my problem.