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MichaelP

PID Controller Programming. Cone 05 Bisque and Cone 5-6 Glaze Firing Schedules

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I'd like to post my notes on programming a simple Ramp and Soak PID temperature controller for Bisque (Cone 05) and Glaze (Cone 5-6) Firing. The Glaze Firing Schedule was adopted from the book "Mastering Cone 6 Glazes" by John Hesselberth and Ron Roy. The Bisque Firing Schedule is based on suggestions found in many books and other sources of information.

 

Note that the controller is programmed in Celsius. The controller operates an SSR (Solid State Relay) which switches the kiln on and off (Note: if you use a mechanical or mercury relay, use Cycle Time value from 20 to 40 instead of "5" in the PID setup).

 

My controller is capable of programming 50 steps. I allocated steps 1 through 7 for Bisque Firing program and steps 15 through 21 for Glaze firing.

 

I hope someone may find these notes helpful for setting and programming his/her own PID controller.It'll be quite easy to substitute the temperature and time values if you want to change the curves.

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Kathryn 14 and sheppard.lin like this

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Here is something else that can be helpful to program Cone 5-6 in digitally controlled kilns. This is a way to emulate Cone Firing while making a custom program in Ramp and Hold Mode of Skutt and other controllers, including PIDs.

 

Choose the rate of the temperature increase during the last 200F of firing and see what temperature your kiln should reach to achieve Cone 5, 5 1/2 or 6. Each graph corresponds to one of the Cone #.

 

This is based on the data provided by Orton for self-supporting cones.

Cone 5.doc

Cone 5.5.doc

Cone 6.doc

Cone 5.doc

Cone 5.5.doc

Cone 6.doc

sheppard.lin likes this

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I'm interested in what type of controller you have. Is it a commercial or  a home brew? How many zones can you control and do you use or can you use type S thermocouples?

 

I have an older Bartlett for my kiln that has type s and 3 zones, which I find very helpful but have wondered about how to write a program for a homebrew controller.

 

Looking forward to digging into this with you, Wyndham

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Wyndham,

 

A few months ago I made a stand alone single zone kiln controller based on a PID. It can be used with any kiln that doesn't have a controller. One will only need to install a thermocouple and do simple rewiring to bypass any controls the kiln may have. The PID I used accepted K type couples.

 

Since then I bought Scott with a built-in controller, so my second post can be applied to the Ramp/Hold mode of its KilnMaster as well as any other controller.

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After reading your post , I googled PID and it seems that most are a single zone as your first one was. The Bartlett I have is only about $200 new and has all the ramp/holds and set for type S

I have one of these on one kiln but was thinking how others might be working.

Cost wise Bartlett is more convenient I think.

Thanks Wyndham

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Wyndham,

 

Indeed, it's a very nice and reasonably priced controller for those who need multi-zone control and use S-type thermocouples. I was a bit surprised it didn't have outputs for SSRs (solid state relays) though.

 

However, for an average Joe who has a single zone kiln with a K-type couple this controller is an overkill, IMO. Considering the extras he will need to add to make a complete device, it might be wiser just to buy one of the stand alone (a.k.a. "wall mount") controllers. In either case he will get a very convenient device with a nice interface, but the interface adds $200-$300 if compared with a generic PID-based kiln controller.

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I use a Bartlet controller to control 3 of my electric kilns one at a time.  My kilns were manual so I changed the wiring of the kilns so that the controller bypasses the switches.  Since the kilns have two rings I changed the Barlett to a 2 zone controller, and now have two zone control on each of the kilns.  The Bartlett comes with the outputs all ready there for up to 3 zones and up to 3 thermocouple inputs.all of the same type. in my case type K.  I have to change to which kiln I am using by means of the power cords and themocouples.  It has been working fine for over a year now.

David

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A manual kiln with balanced elements can benefit from a Wall Mounted controller.  On the other hand if your manual kiln doesn't fire evenly top to bottom (less than 1 cone difference), a Wall mounted controller can't help much except for the convenience. 

David

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I'm seriously concidering buying this unit.  I have several old Duncans wiht manual dials and kiln sitters.  Recently one of the temperature switches went out.  To repair back to orignial would be about $50, to upgrade might be $150.  Has anyone dealt with this company or similar?

 

http://www.thermomart.com/Dual-Digital-Temperature-Controller The controller has a 50 segment ramp and hold program

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It Looks okay especially with a solid state relay. It looks like it is rated for 40 amps, so check your existing kiln for amp rating you may be able to get a higher rating from them. You will have to make your own program as It doesn't have the features of an Orton programmer, or any other programmer meant specifically for potters. Which means no sensing that the kiln is  firing faster or slower than intended so no compensation for this and 

no guarantee of the proper heat work.  Also all you are getting are the parts, you will have to mount them  in an electrical box and run the power cord plus have a receptacle for your existing kiln to plug into the box. But you could still make a program of your own that will give good heat work, but be carefull as to how you program for the last 200 deg F because this controller will not adjust the ramp or time in case your kiln can't go at 108F or 120 F ramp that some controllers use in there glaze programs.  This is made in China so I would want to be sure of what kind of support you can get.  There are plenty of  American made pid controllers available but in most cases they are for industry and they don't sell a package of parts for pottery kilns, that is for you the customer to choose.

David

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I'd like to post my notes on programming a simple Ramp and Soak PID temperature controller for Bisque (Cone 05) and Glaze (Cone 5-6) Firing. The Glaze Firing Schedule was adopted from the book "Mastering Cone 6 Glazes" by John Hesselberth and Ron Roy. The Bisque Firing Schedule is based on suggestions found in many books and other sources of information.

 

Note that the controller is programmed in Celsius. The controller operates an SSR (Solid State Relay) which switches the kiln on and off (Note: if you use a mechanical or mercury relay, use Cycle Time value from 20 to 40 instead of "5" in the PID setup).

 

My controller is capable of programming 50 steps. I allocated steps 1 through 7 for Bisque Firing program and steps 15 through 21 for Glaze firing.

 

I hope someone may find these notes helpful for setting and programming his/her own PID controller.It'll be quite easy to substitute the temperature and time values if you want to change the curves.

MichaelP, I can't thank you enough for this information. You have saved my sanity by helping me understand the process. I bought the device without any knowledge but wanting my own affordable kiln.

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