JLD612 SSR cycle time

garbear
Posts: 5
Joined: Thu Jan 06, 2011 8:47 am

JLD612 SSR cycle time

Postby garbear » Tue Dec 24, 2013 9:03 am

I have built a custom sausage smoker with an inside volume of approximately 18' x 24" x 4o". It has a 1500 watt heating element that is controlled by the JLD612 using a SSR. The smoker walls are 2" think with thermal insulation and it is equipped with a small fan that circulates smoke/air within the smoker to help keep the vertical temperature gradient more even as the element is at the bottom of the smoker. Operating temps are between 140-180 degrees F. I have auto tuned the unit and it works very well. However, I have noticed that once the smoker has reached the set point temperature that the relay seems to cycle too often (around once every two seconds or so). I would think that this cycle time could reduced to avoid excessive switching of the SSR even though it is rated at 60 amps (oversize factor of 3) and equipped with a large heat sink and cooling fan for working in the summer months. So I have a couple of questions...

1) Is the fast cycle time normal? What parameters can I change to slow the switching even if I sacrifice some temperature accuracy as I don't really care if I over/undershoot by a couple of degrees. I understand that changing some of the P, I, and D parameters as well as the SouF and Ot parameters can have serious consequences if not done correctly.

2) Also, does the set temp during the auto tune procedure matter? I initially tuned it to 200 degrees but the smoking process I use call for various times of cooking at 160, 170, 180, etc. I typically change the temp by manually increasing the set temp by using the increase button (^) on the unit. Is this any different than using the "0001" menu and entering my desired temp as the SV parameter? In essence, by manually pressing the (^) button to increase temp am I ignoring auto tune parameters that would be used if I set the temp as the SV parameter? Or is it the same thing?

I've attached a pic of the smoker in action on a snowy day. Overall, I'm happy with the controller just need some advice on fine tuning.

Thanks in advance!

-Gary
photo.JPG

richiem
Posts: 270
Joined: Mon Jan 03, 2011 3:47 pm
Contact:

Re: JLD612 SSR cycle time

Postby richiem » Thu Dec 26, 2013 2:21 pm

Nice work!

1) Yes, that cycle time is normal and it does not cause any problems for the SSR or the heater. Note that you can always just run the JLD612 as a straight thermostat, since precise temp control is not really needed for your system. Just consult the manual for regular on/off operation around the set point. Give it some hysteresis using the Hy setting -- I would think 2 or 3 degrees would be about right.

2) Auto tuning establishes the PID parameters for your system; after that, altering the set temp doesn't change anything but that one parameter. Your method of temp adjustment is just fine.

garbear
Posts: 5
Joined: Thu Jan 06, 2011 8:47 am

Re: JLD612 SSR cycle time

Postby garbear » Fri Dec 27, 2013 1:59 pm

Richiem,

Thanks for the help. I would like try using the controller as a simple thermostat. Right now I have the controller "outY" parameter set to 2, which has J1 and J2 relays as alarms and the SSR PID output on the "SSR" terminals. Does changing the "HY" parameter in this configuration have any effect? OR do I first need to change the output to 1 (where J1 is alarm output, J2 is PID output controlled by SV, and AH2 and AL2 values are not used, and SSR outputs are turned off) and then rewire my SSR to the J2 relay instead of the SSR terminals? The description in the manual I found says both output control 1 and 2 use the PID parameters, however I am guessing that there is a misprint and output 1 simply uses the J2 relay in conjunction with the SV, acting as a simple thermostat (as you previously described) with the "HY" parameter dictating the switching interval. Please let me know if I'm off base here or if I'm missing something. Thanks in advance!

-Gary

richiem
Posts: 270
Joined: Mon Jan 03, 2011 3:47 pm
Contact:

Re: JLD612 SSR cycle time

Postby richiem » Fri Dec 27, 2013 10:12 pm

For a simple heating thermostat, set Outy to 3, and Rd to 0. See Fig 3 in the manual and note the effect of Hy in that Fig. Also note the value setting of Hy depends on the thermo probe you use. I think, but am not certain, that a Hy setting of 0003 using the Pt100 probe with the Pt10.0 setting, the Hy will be 0.3 deg, but using the Pt100 probe with the Pt100 setting (no decimal), the Hy setting will be 3 deg. This latter combo is what you want -- ultra fine control is certainly not needed here.

Good luck, you are close.

garbear
Posts: 5
Joined: Thu Jan 06, 2011 8:47 am

Re: JLD612 SSR cycle time

Postby garbear » Fri Dec 27, 2013 11:04 pm

Richiem,

Thanks again for the info. Part of my confusion is that I have been working from what I assume is an older or inaccurate version of the manual for the jld612 that I got from a quick internet search. Upon downloading the one from the light object website I now see the outy options 0-4, the manual I was using only showed three options of 0-2. I'll try this out and see what happens.


Return to “Temperature Controller”

Who is online

Users browsing this forum: No registered users and 2 guests