JLD614 ... I must be an Idiot

[jjones3570]

I have a jld614 and all is not well. I went through the initial setup (0089 method) accepted the defaults except a type K TC, and set to Fe. instead of Cel. I am wanting to run a kiln setup like this: http://www.skutt.com/pdf/service_manual ... 7-1027.pdf. and I have one kiln master controller that is bad. The kiln master controller has the ability to ramp / soak which is fine, but I don't need that for general ceramic firing. I want to implement the jld614 in place of the bad controller for said "general firing". Now I did download the newer jld614 manual, and referenced the setup for a standard relay, which in my case I am switching 3 relays, but it's only 12vdc, so it should be able to do all 3 at the same time.?. From the manual it appear I have everything hooked up correctly, but I have been wrong before. Actually I don't even think I know how to turn it on, although it is displaying numbers.

I do not really understand, in this instance, the relation of J1 J2 to positive and or negative. I just want to be able to set a target temperature and let it get to it and cut off.

Any help would be greatly accepted.

Thanks, Idiot...aka jjones

[richiem]

I'm not familiar with the JLD-614 -- is it similar to the JLD-634?

I looked at the wiring diagram you linked. The relays are large 2P1T contactors, and are likely to have fairly substantial coil currents even though they are 12V coils. It isn't clear whether these contactors/relays are operated by DC voltage/current or AC voltage/current -- it matters which very much.

Provide a bit more info and maybe we can help here:
1) Relays -- AC or DC?
2) Rated coil current per relay in amps?

[Tech_Marco]

Rich:

The JLD614 is identical to JLD612. The only difference is the the case layout and the back plate terminals


Marco

[jjones3570]

sorry they are 12dc for the switching signal and they switch 220vac 1Phase.. by name and make are as follows:

potter & brumfield
t92p7d22-12
NO. 30 amp @ 277VAC
20 amp @ 28VDC
1 HP @ 120 VAC
3 HP @ 240 VAC
TV10 @ 120VAC
5Ka rms sym 240vac short circuit when protected by a class k5 fuse

Thats all I can tell ya. The kiln industry sells these thing for $26+ each, I happen to find them on the net for $7+/-. hence the 2 year mechanical engineer wanna be in me. plus I 'm just a cheap skate. But this should be straight forward so I don't understand what I am missing. n the "outy" part of the system settings, I thing I have tried 0,1,3, & 4 seeing how I am trying with a normal relay. If I read correctly the note in the manual says Vref can be ac or dc. so im dc.. I think..

I dunno, hope this helps..

[richiem]

OK, these relays have a coil current of about 140mA DC at 12VDC across the coil, which means that driving three of them in parallel will need about 0.5A from a 12V DC source. The 614 does not supply this coil power and its SSR output cannot be used to operate them. You need an external source of 12V DC connected to the J2 relay in the controller, with the output from J2 feeding the three relay coils. The 12VDC power supply does not need to be tightly regulated or even very low ripple -- a "battery eliminator" from a car audio store or Radio Shack that can supply 1A or even a "wall-wart" 12VDC supply with a 1A rating will get the job done.

In my opinion, you want to use the controller in thermostat mode as discussed in the previous couple of posts here, but using OutY = 4. In this mode, the J2 relay in the controller provides differential control (SV - Hy) to the three relays. The J2 relay is normally open, and closes when the diagram in Fig. 3 in the manual shows "latched," sending DC to the relays:

Set OutY = 4
Set Rd = 0 (heating)
Set SV to whatever temp you want the kiln to run at.
Set Hy to a fairly large value, say 20 deg so that there is a decent size hysteresis dead-band due to the high temperatures in your system, so that the temp will drop 20 deg. before the heat comes back on. If this works, you can try reducing the value of Hy if you want tighter temp control, but I wouldn't go under a hysteresis of 10 deg F.

You could use big SSRs for the relays, but you'd need two of them in place of one of the mechanical relays, making 6 in all -- expensive. If the P&B relays are working, stick with them.

Hope this works.

[jjones3570]

If I am not mistaken, the extra 2 wires on the kiln diagram actually provide 12vdc power to the kiln controller and has a 1zp fuse protecting something, could that not take the place of an external, for lack of better words, power supply for the switching power? and yes sometimes i suffer from typoneese, so be gentle with comments. lol.

Just Thinking.
thx

[richiem]

Somewhere in the original controller is a power supply -- at minimum a rectifier and filter capacitor, or perhaps an LM7812 IC regulator (which is what I'd use) -- that supplies 12VDC for the relays, switched by the original controller. If you can find it, you can use it, and it will do the job nicely, since it already does.

Good luck.

[jjones3570]

Thanks for all your help so far. I have a couple more questions if you could bare with me.
1. the setup you described earlier with supplying power to j2... could I get a quick sketch of that..?..plz..kind sir..lol
2. Was the jld614 my best choice? or should I have gone with a "more robust" ramp / soak type controller..?


Thanks

[richiem]

JLD614 is a fine choice.

System too simple to draw. Use a 12VDC power supply (the one in the old controller may serve, if it is accessible to get at the connection that is always hot when the power is connected, but it may be easier to use a 12V 1A wall-wart supply from Radio Shack).

Connect the 12VDC + output to terminal 13 of the JLD614 (assuming the terminals are numbered the same as the JLD612).

Connect JLD614 terminal 14 to the + wire running to the relay coils.

Connect the - wire coming from the relay coils to the 12VDC - output.

If the wires to the relays (or the relay connections) are not designated for polarity, then it doesn't matter which one you connect to terminal 14 and to the 12VDC - output.

[jjones3570]

Good afternoon and thanks for the help, I did finally decide to quit trying to make this hard, I was testing this on my already working bigger kiln at our main location. So I took it where it was needed, to a bare kiln, a new 50amp ssr and hooked it all up. The only thing I changed is i went back to setting 2 for the "outy" ran the sv to 1200d/f and i noticed that it did not cut off at 1200 degrees. In the attached picture, I do believe I'll have to set it up like the example. My question is why is the alh2 & all2 a hundred degrees lower that alh1 & all1? What does this do, or is it an alarm incase the temp drops below that temp within a certain time span.
On another note, I am interested in two temperature goals for this kiln. 1. is cone 06, 1828d/f and cone 04, 1945d/f. Will I have to change the example picture section of the program to switch between the two?

thanks,
Jay

[richiem]

Hi Jay -- no attached picture.... So in mode 2, you have PID control of the SSR, which means that as the PV nears the SV, the controller will start to modulate the SSR control by turning it on and off. When the PV temp reached 1200 dF, did the red LED SSR control indicator on the controller stop blinking? Did the one on the SSR do the same, or did it stay on?

Is it possible that somehow wiring was incorrect and power just stayed on to the heater? With the SV at 1200, did the PV indicator show the correct temp? So many things can go wrong.

The alarm values are totally arbitrary -- you can set them however you want to or need to. In mode 2, they are just relays to control externally powered, external alarms, like lights or horns, etc. The manual examples are just examples, not recipes.

More info needed.

[jjones3570]

You could use big SSRs for the relays, but you'd need two of them in place of one of the mechanical relays, making 6 in all -- expensive. If the P&B relays are working, stick with them.

Hi again, If i was to use 6 big relays exactly how big would they need to be? I read in another post that someone suggested one 5 times bigger than the load drawn. I understand inductive start ups that motors can have but is it the same with heating elements? on the initial post with the link to the kiln's manufacturing relays, we have six individual elements in the kiln, with three relays. Now obviously somehow one aforementioned contactor can power 2 sets of elements. I test the amperage on this one wire leading to the positive side of the element and it reads 17 amps for two sets, and roughly half that when I measure the last leg of it going to the second element (it is daisy chained I think it's what you would call it). and the same for the negative side. Why can one ssr not do 2 sets of elements when both elements are only pulling 17 amps? At a 125%, when interrupting one side beit pos or neg, it would only max at 21.25 amps So in my simple mind a 25 amp ssr should suffice. Unless the 125% rule of thumb is only for sizing wire and breakers.?.?but I think I just answered my own question, if elements are inductive then each element at, est high 9amps x 5 = 45 so a 50 amp ssr would suffice for each element....?...So just set up 6 of those one a 8" piece of 2" sq. alum tube with a small laptop cpu fan running across it I'll be set. unless one of you crushes my hopes and dreames...just kidding..input please...no punn intented....

Thanks in advanced..

[richiem]

Edit -- I just checked a spare SSR I have, a 90A unit. It's control current is 5.5mA at 3V and 10mA at 8V. I think that the controller *may* be able to drive 6 of these in parallel, but there's no way to know for sure without actually trying it.

The heater elements are essentially resistive -- no inductance of any concern. Current ratings of contactors and relays are usually spec'd at 2 or 3 times the expected load current for reasonable life. SSRs have to have much higher current ratings because they generate a lot of heat, and without great cooling, the current rating derates very (very!) quickly. So I usually think of having an SSR current rating of at least 5 times the actual current, and more is always better. 90A SSRs are fairly common and also fairly cheap, so that's where I would go in your set-up; I am using a 75A SSR on a stock heat sink without a fan for my 13A (120V - 1500W) heater and the heat sink gets toasty when the SSR is on all the time during initial heat up. Given the current ratings of the heaters, you can certainly power two heaters from a single SSR, but you'll need two SSRs if you want (or need) to switch both sides of the AC line.

The contactors can be double pole to handle switching both sides of the AC line, but SSRs cannot, so you need two SSRs to replace one double-pole contactor. That's going to be a few SSRs and then you have to consider if the output from the controller can drive all of the SSRs in parallel. I think the controller can supply 8V open-circuit and 40mA into a current sink -- I'm not sure how much current the SSRs typically need -- I've only ever used one SSR at a time, and that works great. There are ways to boost the current output from the controller, but we're starting to talk circuitry -- transistors and power supplies or relays and power supplies, etc.

2ND THOUGHTS --- Just use a DC controlled SSR to drive the six main heater SSRs, and use AC controlled (120V or 240V) SSRs for those -- no problems with having enough control current. In fact, one of the six can be the DC controlled one, whose output drives its heater combo and five AC controlled SSRs, saving one SSR.

Your idea for a heat sink is good providing the wall thickness of the (2"?) square tube is fairly large -- at least 1/8". But you're talking a number of SSRs and they do get hot, so a fairly large centrifugal blower, say 200 cfm, shooting at the open end of the tube might be a good idea, and in a somewhat dusty or dirty environment, be sure to put a filter over the fan's intake....

[jjones3570]

Hey me again, This controller can go to a desired temp and then shut off correct, I do not need it to maintain the temp, but just get there asap and once it gets there cut off or break current.

Thanks...

[richiem]

I think the way to do that is to just set a very large temp differential between the on temp and the off temp -- but there has to be two temp points or the controller doesn't know to start up the heat. If you set a large differential -- for example, SV = 600 and SV-HY = 20 (or something well below typical ambient), then it'll go to 600 then stop until the temp gets down to 20, giving you time to manually shut things down.

Maybe you want to look at the JLD-634 ramp-soak controller, which will let you do a single ramp up and then off, I think.