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Old 05-03-2012, 10:31 AM
mike3 mike3 is offline
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Chromalox 2104 temp. contrl Help

Hello..

I am new at Glass.. and have read most of Mark Wilsons stuff I built my Kiln controller along his design.. ....It is Based on A Chromalox 2104 controller I got surplus.. I can get it to work ON/OFF .. but am having trouble learning to use some of the other features.. such as Ramp/Soak..understanding how to program the controller is the problem... I am trying o fuse 6-8" glass disks between 5-6 layers 1/4" thick into telescope mirror blanks.. using float glass.. I have ramp up the temp slowly 1200f then fast to 1700f .. for about 10min,, then fast back to 1200f then slowly back to room temp... then to anneal.. I have to remove from mold .. put glass blank back into kiln .. ramp slowly back to around 900-950f.for 4-8 hrs. then slowly back to room temp... the glass will be 1inch think for 6" disks.. and 1-3/8 for 8" disks.. the manual is at this link.. http://www.chromalox.com/catalog/res...PK-2104-QI.pdf .. http://www.chromalox.com/catalog/res...IM-PK-2104.pdf If any smarter than me person could help that would be wonderful..If I could at least get some idea what does what. and why

Any help would be greatly appreciated.. I am at wits end.. googling I can't seem to find any thing on programming these things.

Regards.. Mike

Last edited by mike3 : 05-03-2012 at 10:43 AM.
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Old 05-03-2012, 02:48 PM
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crec crec is offline
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Re: Chromalox 2104 temp. contrl Help

Hi Mike.

Ah the joys of setting up a new digital controller. Couple of things. I am making some assumptions like: You have wired up the controller to a thermocouple and have configured it to read the thermocouple. You have wired up the controller to drive a relay or SSR to power your kiln and that the controller is configured properly to drive relay or SSR. If these assumptions are not correct let me know so they can be corrected first. Please note that when using a relay or SSR to operate a kiln the controller will cycle the devices on and off. The way that the controller maintains the temperature is by turning on the relay or SSR for a period of time and then turning it off again. Kind of like hitting the gas pedal on your car all the way on and then fully releasing it. If you could do it quickly enough the speed would appear constant. In this case the temperature appears constant. The controller has three variables that need to be entered to be able to do this. They are the PID (proportional, integral, derivative) values. On page 35 of the manual (40 on my reader) you will see Pb1 (proportional band), Ar1 (reset = 1/integral), rAt1(rate = 1/derivative). You need to make sure that there is a value in the Pb1 entry. If it is zero the controller will only work in on/off mode. Set the Orn9 value to 0 so that if the thermocouple breaks it will turn your kiln off.
Now it sounds like you want to program a ramp/soak cycle so set the rrAt value to off. It is used to allow you to set a single temperature value and have the controller go there directly. Make sure the Cont value is set to HEAT, rSP = off, Enti = none, Au=none, Aout = none. rSEn=ON. The last one is important because it turns on the ramp/soak section of the controller. From there go to page 43 of the manual. Don't worry about events. Select the time units you would like to work in. If you want to work in minutes select minutes ( 1.5 hours would then be entered as 90 minutes on the controller). So lets say you wanted to go to 1000 F in 90 minutes and hold there for 30 minutes then go to 1500 f in 30 minutes and hold for 15. The first interval time would be 90 and the temp would be 1000. The second interval would be 30 and the temp would be 1000. The third interval would be 30 and the temp would be 1500. The forth interval would be 15 and the temp would be 1500.

Carlos
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Old 05-03-2012, 09:40 PM
mike3 mike3 is offline
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Re: Chromalox 2104 temp. contrl Help

Fantastic Carlos!...

Thanks for your Great reply.. Yes I have the controller connected to 2 SSR's powered by a 12vdc supply I built..and the controller is set to a "K" type T/C ... I think I see what you mean by fast on and off ,, I had the setup connected to a CFL bulb..for testing and it flashed on and off very fast..I will set the controller as in your post tomorrow .. after work.. and try the ramp/soak examples and get back to you.. I really appreciate the help.. I think I might be understanding somewhat reading what you wrote and refering to the manual ..what is the Stby standby setpoint for? And on the interval/segments.. how do I get the controller to go from one to the other or is it automatic?.. and on the PID setting where would I set them say for 1700F? and the Guarantee Soak?

Again Thanks for your help..

Mike
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Old 05-04-2012, 09:28 AM
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Re: Chromalox 2104 temp. contrl Help

Morning Mike

Ok you can use a CFL for testing, but a regular filament style light bulb works better. CFLs really don't like cycling like that. The standby setpoint is the temperature setpoint that the controller should default to when it is not running a program. I usually set it lower than the kiln will ever get to, so that the PID equation does not start putting heat to the kiln when I don't want it running. In other words I often will set it around 30 or 40 F.

On the intervals/segments the program will automatically advance through the segments when the programmer is put into the run mode. So if you have a segment that is thirty minutes long, the programmer will take thirty minutes to accomplish it's task (ramp or soak) and then go on to the next segment in the program. If the next segment is empty the program is finished.

Guaranteed soak is a tolerance band. Basically if you tell the controller to go to say 1500 F and you tell it to get there in say 5 minutes the controller would calculate the number of degrees to rise every minute to get there. In this case the controller would be going at just under 300 F/minute. Now the controller can do the calculation and advance the numbers that fast, but your kiln could never keep up. If you had a soak of say 5 minutes in the next segment the controller would then count the 5 minutes down and be finished long before your kiln ever came up to temperature. The guaranteed soak allows you to put in a tolerance. So if you were to put in a guaranteed soak band of 10 F the controller would still try to run the temperature up at the crazy rate of 300 F/minute, but the 5 minute soak would not start until the temperature of the kiln was at 1490 F.

The PID settings are probably the hardest part to get. Every controller is a bit different, the way the kiln is built, the size of the elements, and the placement of the thermocouple all play a part in setting them. That said there is an auto tune feature in the controller. From the manual (page 29) you can set in a set point and then tell the controller to run an auto tune cycle. You need to have the temperature of the kiln be within 50 F of the target temperature to do this. So for 1700 F you need to have the kiln temp between 1650 and 1750 with the setpoint at 1700 for the auto tune to run. I would actually run it at a lower temp first like 1000 F and then see how well the values control through out the operating range of the kiln.

Just so you know I will not be around the board this weekend, as I have a show.

Carlos
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Old 05-04-2012, 10:50 AM
mike3 mike3 is offline
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Re: Chromalox 2104 temp. contrl Help

Thanks Carlos...

I think I have enough to digest.. right now anyway.. have a great weekend..

Mike
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