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More Kiln Adventures

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lbailey
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More Kiln Adventures

Postby lbailey » Sat Sep 23, 2017 10:03 am

So I installed an SDS TAP controller on my Olympic GF314ETLC this week and everything seems to be working properly. I especially like the diagnostics, logging and will be enabling Wif-fi with the mobile app next week.

However, I am puzzled by the fact that the controller displays a resting temp of 89F when the kiln is open and cool, but the actual ambient temp in the room is 75-76F. I did not change the thermocouple. Couple of questions:

- Is it normal for this gap to be so wide after changing a controller? It has a setting to change the TC offset, but just seems odd that it's about 14F difference.......

- The only temp gauge I have is one of those infrareds from HF. (I bought it to check temps before handling warm glass, molds, etc.) It also reads 75F in the vicinity of the TC and even on the TC itself. Is it accurate enough to use to set the offset or do I really need a digital temp gauge with a Type K TC?

- If I need a more serious temp gauge can you guys recommend one, and the sensor that best suits? (I'll probably build a kiln or two from scratch in the future so I don't mind getting one that is reasonably priced and of good quality)

- If a TC or sensor needs to be in the kiln to monitor and log temps how does one get it into the closed, firing kiln?

I suspect that many of you will think "Leave it alone and just go make glass.....". But I really enjoy the tinkering opportunity too.

Thanks

Kevin Midgley
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Re: More Kiln Adventures

Postby Kevin Midgley » Sat Sep 23, 2017 6:20 pm

I was once told that in order to get an accurate connection with thermocouple wires for a pyrometer that you needed to scrape the surface of the wire ends.

Don Burt
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Re: More Kiln Adventures

Postby Don Burt » Sat Sep 23, 2017 11:12 pm

lbailey wrote:clip

- If I need a more serious temp gauge can you guys recommend one, and the sensor that best suits? (I'll probably build a kiln or two from scratch in the future so I don't mind getting one that is reasonably priced and of good quality)

clip


Isn't the best sensor for serious temperature measurement at the temps we're interested-in, a thermocouple?

I don't feel I need to know the difference between the room temperature and the inside of a kiln. I'd like to know the variance between the measured temperature in my kilns when they're above strain temperatures and the temperatures quoted by books and manufacturers of glass. I bought pyrometric cones to get a baseline reading of my kilns, so that I could answer the questions about element life and thermocouple quality as they got older. The temps that I fire-to vary by quite a bit, and the number of cones you need to capture the various states turn out to be a few, and the few that I wanted are hard to find in the format that I wanted them. When I finally accumulated all the cones, over time I got samples from firings and kept the result cones in plastic bags in my studio for reference. Its been a few years and now I've forgotten why I gave a shit in the first place.

I'm thinking if start wondering about temperature measurement again, I'll acquire two thermocouples and take a reading with each. Then I'll declare my measurements accurate and everyone else's suspect.

Ed Cantarella
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Re: More Kiln Adventures

Postby Ed Cantarella » Mon Apr 30, 2018 3:35 pm

Look in your instructions - there is probably a thermocouple offset, specifically to change this niggling little issue. I personally like the cold kiln to show room temp within a few degrees of reality. I actually expect them to read a hair lower than air temp, since they are sitting on a concrete floor in a basement, which is cooler than the air too.

Don Burt wrote:I'm thinking if start wondering about temperature measurement again, I'll acquire two thermocouples and take a reading with each. Then I'll declare my measurements accurate and everyone else's suspect.
That just makes too much sense. :)
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.

lbailey
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Re: More Kiln Adventures

Postby lbailey » Tue May 08, 2018 3:55 pm

Update on this, the TAP tech rep says that the resting temp displayed is actually the temp of (or around) the controller circuit board. Which is fine I suppose, but explains the delta.

I've used the controller for several months now and really like it.

Ed Cantarella
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Re: More Kiln Adventures

Postby Ed Cantarella » Thu May 10, 2018 7:11 am

lbailey wrote:Update on this, the TAP tech rep says that the resting temp displayed is actually the temp of (or around) the controller circuit board. Which is fine I suppose, but explains the delta.

I've used the controller for several months now and really like it.
I think that rep may have snowed you. If your kiln is open and cool(like you haven't fired in a day or two) seems odd the circuit board would be that warm. I suppose if you were really curious you could shut off the power to the kiln, let it sit for a few hours so it is definitely cool (no heat from internal transformers,etc. and turn on to see what it says. My guess is the rep didn't want to go through explaining how to get to the thermocouple offset sequence, if it has one. Curious.
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JestersBaubles
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Re: More Kiln Adventures

Postby JestersBaubles » Tue May 15, 2018 11:19 pm

The controller board has WiFi, and most likely has a CPU. They are going to generate heat.

The rep's explanation is "sort of" right. Thermocouples are "dumb pieces of metal" -- two dissimilar metals attached at one end that generate a very small voltage. The voltage change is generally linear with a change in temperature. The "dumb metal" needs a reference temperature in order to derive the ambient temperature in the kiln. That reference temperature is being measured on the controller board. So... the heat from the WiFi/CPU means that the reference temperature is going to be elevated, and thus, the thermocouple temperature is elevated.

I work with dataloggers all day. Some of them have very good internal reference temp sensors and some of them don't :mrgreen:

Dana W.

Ed Cantarella
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Re: More Kiln Adventures

Postby Ed Cantarella » Fri May 18, 2018 3:11 pm

JestersBaubles wrote:The controller board has WiFi, and most likely has a CPU. They are going to generate heat.

The rep's explanation is "sort of" right. Thermocouples are "dumb pieces of metal" -- two dissimilar metals attached at one end that generate a very small voltage. The voltage change is generally linear with a change in temperature. The "dumb metal" needs a reference temperature in order to derive the ambient temperature in the kiln. That reference temperature is being measured on the controller board. So... the heat from the WiFi/CPU means that the reference temperature is going to be elevated, and thus, the thermocouple temperature is elevated.

I work with dataloggers all day. Some of them have very good internal reference temp sensors and some of them don't :mrgreen:

Dana W.
All of this is true - a reference is needed. Which I why I suggested she shut off the power and see what it reads when it first comes on after it has moderated to room temp. Even the most basic controllers have the same situation to deal with to a degree since there is the step-down transformer within a few inches. So they give you an offset partly so you don't feel crazy because your cold kiln reads 89 but the room feels chilly. :mrgreen:
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.

Ed Cantarella
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Re: More Kiln Adventures

Postby Ed Cantarella » Mon May 21, 2018 11:25 am

Pg.40 of the manual. :mrgreen: Offset https://www.kilncontrol.com/files/8814/ ... lease2.pdf
"6.5.9 Thermocouple
Thermocouple offset can be used to correct a drifting thermocouple. A user defined
thermocouple offset can be programmed with allowable values between -50 and + 50. This
allows for user corrections to thermocouple deviations within this range of temperature. When
this setting is applied, the user defined value is added to the temperature detected by the
controller. This offset is applied consistently across the range of input temperatures. The setting
is retained when power is removed from the controller.
To modify these settings, perform the following steps:
• From Home Screen, press MENU
• From Main Menu, press SETTINGS
• From SETTINGS, press Thermocouple
• Select the “NEW” text entry field, enter the value with the virtual keypad, then press
ENTER"
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.

lbailey
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Re: More Kiln Adventures

Postby lbailey » Mon May 28, 2018 11:03 am

Yep, understand the offset feature and steps to change it. But in reality my previous schedules (100s using the original Bartlett 1000) seem to work just fine with no offset. I may do some more extensive testing later after my new studio is finished and everything comes back out of storage. That may be Fall or early Winter..... :(

And Ed, I am a guy. Common mistake, no harm done.......

Ed Cantarella
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Re: More Kiln Adventures

Postby Ed Cantarella » Tue May 29, 2018 9:49 am

lbailey wrote:Yep, understand the offset feature and steps to change it. But in reality my previous schedules (100s using the original Bartlett 1000) seem to work just fine with no offset. I may do some more extensive testing later after my new studio is finished and everything comes back out of storage. That may be Fall or early Winter..... :(

And Ed, I am a guy. Common mistake, no harm done.......
Oooopps.
BOT: Kiln offsets - a lot of kilns come from the factory already offset X amount since the thermocouples and their connections can both effect the readout It sounds like you recently swapped out the controller so something may have changed in a minute fashion. I have 4 Paragons and one Evenheat and when I go into our studio area they read within 2-3 degrees of each other if cool ( I chalk some of that up that up to room position). The offsets are running from -12 to +8 to have them dialed in thus. The last Paragon was showing 8-10 degrees high on arrival, the Evenheat was/is dead-on. Sorry I've perseverated on this a bit, a substantial readout difference would wig me out. :oops:

Good luck on the studio setup - exciting!
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.

lbailey
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Re: More Kiln Adventures

Postby lbailey » Wed May 30, 2018 8:06 pm

Yeah, Brad will tell you I am pretty easily wigged out. I have let this one go without too much stress because the schedules in my logs seem to work just fine with the new controller. Makes me stop and consider what really matters. Lately I've been thinking I need to focus more on intentional design and creativity, much harder (for me....) :-k

JestersBaubles
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Re: More Kiln Adventures

Postby JestersBaubles » Wed May 30, 2018 11:08 pm

Ed Cantarella wrote:Pg.40 of the manual. :mrgreen: Offset https://www.kilncontrol.com/files/8814/ ... lease2.pdf
"6.5.9 Thermocouple
Thermocouple offset can be used to correct a drifting thermocouple.


If a thermocouple were truly "drifting" an offset isn't going to help. Just sayin' ;).

Dana W.

Ed Cantarella
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Re: More Kiln Adventures

Postby Ed Cantarella » Fri Jun 01, 2018 10:22 am

JestersBaubles wrote:
Ed Cantarella wrote:Pg.40 of the manual. :mrgreen: Offset https://www.kilncontrol.com/files/8814/ ... lease2.pdf
"6.5.9 Thermocouple
Thermocouple offset can be used to correct a drifting thermocouple.


If a thermocouple were truly "drifting" an offset isn't going to help. Just sayin' ;).

Dana W.
I and the good people of Paragon have to disagree Dana - that is exactly what that setting is there for. :wink:

Paragon's explanation on the why.
You can’t actually adjust the temperature reading of the thermocouple. But you can adjust the way your digital controller interprets the signal that it receives from the thermocouple. Why would you want to do that?

1) You have replaced the thermocouple in your kiln, and the new one does not read exactly the same as the old one.

2) Your kiln has a Type-K thermocouple that has drifted in temperature. (The longer it is exposed to ceramic temperatures, the more it drifts in temperature.) A Type-K thermocouple can vary as much as 36F / 20C over its life span.

3) You want to adjust the thermocouple so it matches the bending of a pyrometric witness cone in Cone-Fire ceramic firings.

The thermocouple reading is adjusted in Thermocouple Offset. This is the term used by the two most common brands of controllers, the Orton and the Bartlett.
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.

JestersBaubles
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Re: More Kiln Adventures

Postby JestersBaubles » Sat Jun 02, 2018 12:55 am

It's semantics, but there's a difference between a thermocouple that "is drifting" and one that "has drifted" ;). If a thermocouple is truly drifting, it means that the measurement is always moving (usually due to noise). An offset can't correct for a continuously changing signal. A good noise filter could, however :).

And I apologize for the day job encroaching on our art space!

Dana W.

Ed Cantarella
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Re: More Kiln Adventures

Postby Ed Cantarella » Sat Jun 02, 2018 7:23 am

Dana - nobody said anything about a constantly changing ouput.As Paragon explains it is not uncommon for thermocouples to slowly move several degrees off over time or suddenly when things are changed - changing the length of one of the leads will change it greatly. The OP changed controllers and was getting 89 in a normal room temp situation "I am puzzled by the fact that the controller displays a resting temp of 89F when the kiln is open and cool, but the actual ambient temp in the room is 75-76F."
Your day job is with thermoresistors which are referenced to room temp(25c). Most thermocouples are referenced to 0c. And most batches of thermoresistors have a few degrees variance unless they are really top quality - just go to Home Depot and look at the digital thermostats or weather gauges - few degrees difference in a batch of identical units.
Basically you got yourself in a spot and wanted to be argumentative, and then decided you needed to be a smarty with the wink. Give it up, it isn't semantics - you were still wrong. But you learned something possibly. :wink:
And no, an EMF filter isn't going to help an analog circuit measuring induction, which is how a thermocouple works, even in a "digital" controller.
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.

JestersBaubles
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Re: More Kiln Adventures

Postby JestersBaubles » Sun Jun 03, 2018 11:20 pm

Ed Cantarella wrote:Dana - nobody said anything about a constantly changing ouput.As Paragon explains it is not uncommon for thermocouples to slowly move several degrees off over time or suddenly when things are changed - changing the length of one of the leads will change it greatly. The OP changed controllers and was getting 89 in a normal room temp situation "I am puzzled by the fact that the controller displays a resting temp of 89F when the kiln is open and cool, but the actual ambient temp in the room is 75-76F."
Your day job is with thermoresistors which are referenced to room temp(25c). Most thermocouples are referenced to 0c. And most batches of thermoresistors have a few degrees variance unless they are really top quality - just go to Home Depot and look at the digital thermostats or weather gauges - few degrees difference in a batch of identical units.
Basically you got yourself in a spot and wanted to be argumentative, and then decided you needed to be a smarty with the wink. Give it up, it isn't semantics - you were still wrong. But you learned something possibly. :wink:
And no, an EMF filter isn't going to help an analog circuit measuring induction, which is how a thermocouple works, even in a "digital" controller.


Wow. I'm not certain what set you off, but you win. No smiles or winks necessary.

Dana W.

Ed Cantarella
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Re: More Kiln Adventures

Postby Ed Cantarella » Mon Jun 04, 2018 7:00 am

JestersBaubles wrote:
Ed Cantarella wrote:Dana - nobody said anything about a constantly changing ouput.As Paragon explains it is not uncommon for thermocouples to slowly move several degrees off over time or suddenly when things are changed - changing the length of one of the leads will change it greatly. The OP changed controllers and was getting 89 in a normal room temp situation "I am puzzled by the fact that the controller displays a resting temp of 89F when the kiln is open and cool, but the actual ambient temp in the room is 75-76F."
Your day job is with thermoresistors which are referenced to room temp(25c). Most thermocouples are referenced to 0c. And most batches of thermoresistors have a few degrees variance unless they are really top quality - just go to Home Depot and look at the digital thermostats or weather gauges - few degrees difference in a batch of identical units.
Basically you got yourself in a spot and wanted to be argumentative, and then decided you needed to be a smarty with the wink. Give it up, it isn't semantics - you were still wrong. But you learned something possibly. :wink:
And no, an EMF filter isn't going to help an analog circuit measuring induction, which is how a thermocouple works, even in a "digital" controller.


Wow. I'm not certain what set you off, but you win. No smiles or winks necessary.

Dana W.

What? Someone who wanted to argue against a very solid instruction, on this situation in the manual. So now we have mucked up a thread that could have served many after us. One query and one answer that all the common manufacturer's abide by was all that was needed - certainly the reasonable first step. Not sure why you felt the need to pick up the rep's "cross".
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.

Kevin Midgley
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Re: More Kiln Adventures

Postby Kevin Midgley » Mon Jun 04, 2018 11:10 am

However the readers will find all the above information useless if the thermocouple wiring connections are not made correctly as I suggested in post #2 above! :lol:
You at least have to start with good connections before you start observing possible drift.

Ed Cantarella
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Re: More Kiln Adventures

Postby Ed Cantarella » Tue Jun 05, 2018 6:39 am

Kevin Midgley wrote:However the readers will find all the above information useless if the thermocouple wiring connections are not made correctly as I suggested in post #2 above! :lol:
You at least have to start with good connections before you start observing possible drift.
Definitely a good idea since we a talking a few millivolts.
HER last words were, "I'm melting, melting . . . " Dissenting opinions generally welcome for comic relief or personal edification. Sometimes both.


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