JLD612 programming question

[tmorris9]

OK, so I got a JLD612 and this is my first ever PID controller. I have played with it for an hour and I understand how to change the settings and what a few of the settings actually do. Still a little foggy on the use, here is my scenario:

I have a small convection oven that I wish to accurately control the temperature of. It uses a set of electric (110vac 11amp) heating elements. I got the PID controller with a K type thermocouple and an SSR. I have already set it up to read the K type thermocouple and have hooked up the SSR (not to the oven yet, just for testing and learning).

What I am seeing is that it pulses the output when the target temp is reached, the rate of pulsing changes but it's pretty quick (several times a second). I understand that this is probably a more accurate way of controlling temperature but what I was hoping to do is a more simple on/off cycle.

My main use is 275f (yes I set the controller to f). What I would like to do is set it to turn on until the temp is 275 then turn off (no pulsing) then turn back on at something like 270, and repeat.

I just don't really want an 11 amp load turning on and off several times a second.

Can anyone suggest a set of settings to accomplish this? I have read the manual and most of it is just a little over my head. Or after I hook it up to the oven do you think the auto tune feature would come close to doing what I want? I would not mind the pulsing if it was every few seconds or so, is there a way to change that alone?

Thanks!

[cumorglas]

that's why you use the ssr. you don't worry about wearing out the contacts. but if it stresses you out, i know the 7100 can be set to behave as though it is using actual clicky relay and slow that behavior. the 612 probably can too.

but it won't harm your elements. i've used them with ssr driven by a pwm controller with no harm.

[tmorris9]

Not worried about the relay or elements but rather transient surges in the power. Lots of computers and delicate equipment on the same line. I would not worry about it if it were every few seconds but it can be several times per second now. Moving it to a different line is not possible at this time either.

[cumorglas]

on the 7100 the ot is default to 2 you can make this larger (i think up to 199) that will slow it down. i am sure the 612 has similar options.

[tmorris9]

Cumorglas, yea while I don't know what all of these settings affect I thought about that one and it was set to 2 seconds, I changed it to like 5 seconds but did not seam to change the frequency.

I just wish there was someplace that explained in plain English what each setting actually does. I am into electronics big time but just never used a PID so I am not familiar with the meanings.

I searched all over the internet for some kind of help on this but no luck.

I am thinking it might be the SV, AH1, AL1, AH2 or AL2 settings but would like to know what they affect without just guessing and testing each one.

For now, if I don't find someone that knows for sure I plan on completing the hook up and trying the auto-tune and see what the outcome is.

On the good side he uploaded a new manual last night that now shows the symbols as they appear on the unit so no more guessing on things like what "k" is.

Thanks!

[tmorris9]

Well I went ahead and hooked it all up and let auto-tune do it's thing. While it was tuning the temp went over by 11 degrees and under by 11 degrees but once it got done it looks like it's holding at +/- 1 degree.

It is cycling on and off but it looks like about 1 second ea. I can live with that.

I guess I was worried the Auto-tune would not be that accurate but I am a happy camper so far.

I have not tested to see if the thermocouple is reading accurate yet or not but hopefully it is.

Edit:****

Just checked the oven with a known accurate thermometer and the oven is about 37 degrees hotter than the PID says. The thermocouples are next to each other (besides it's a convection oven so the heat is pretty even throughout).

So is there a way to compensate for the difference? (other than doing it manually that is).

Edit again:***

OK I found out how to correct it. I am a happy camper again!

[cumorglas]

the autotune is pretty nice.

you won't see much difference changing the ot from 2 to 5. you gotta make it at least 30 maybe even higher. 30 is the default for regular contactor.

[tmorris9]

I think I am going to be happy with how the auto-tune set everything. It is so much better than the bimetal switch that was in this thing. And that switch was outside the oven compartment. It probably had a 20-30 degree swing. Now I have a 1-2 degree swing.

[Haynes Maple syrup]

Im not very good at setting these things up or understanding the whole PID thing but here goes. I have a temperature controler by fuji but there expensive. I have the JLD612 hoping it would work for my aplication. I make Maple syrup and need to control a 110 volt solenoid to open and drain finished syrup during the evaporation prosess. The unit I have is simple and how it works is out of the box factory set it shows actual temp top screen and botton screen is programable. It also has a 3 degree over temp setting so when the temp that I punch in on the lower screen is met the controller activates the 110 volt solenoid. Then closes when the temp of the syrup lowers by 1 degree. Back and fourth AND if the temp goes over the pre set point by 3 degrees the due to stuck valve or low liquid level it will sound an alarm CAN this controller do this or did I get the wrong one?