rondoc
-
Posts
31 -
Joined
-
Last visited
Content Type
Profiles
Forums
Gallery
Posts posted by rondoc
-
-
On 2/3/2022 at 11:52 PM, Bill Kielb said:
Can you measure the noise? Scope? Or maybe apply 1 mv steady state and see if the reading is stable for for a long enough time for things to heat up. If it still disappears then on to freeze spray …… not a big fan, as these assemblies are not industry proven / hardened.
-
I have the cones 17 thru 20 still. I believe cone 20 is about 2700F. I had a visual disappearing filament pyrometer and a thermoelectric one that I used as well as the cones. I know it is about 2700 F as I melted steel in it by mistake! Steel melts around 2800F. ( BTW this is about 35 years ago so my memory is a bit rusty. I do have my lab note books for reference if anyone has interest. )
-
On 2/5/2022 at 11:21 PM, Bill Kielb said:
SSRs are already zero crossing and optically isolated, just drive them with a few volts dc. Mechanical relays pretty much goof proof easy way to protect against a stuck SSR and he doesn’t need to worry about leakage killing him when loading the kiln. The mechanical relay also easy to interlock through an independent high limit as well if he chooses. The new stuff today is generally good.
What temperature is cone 20 and where do you get cones?
Cones from Orton. The parts were a dry mix of SiC. Kaolin and wollanstonite. The mix was then moistened and pressed into plaster molds. The resultant ceramic is very strong and can take cone10 with no change. I have the exact formula if anyone is interested. If partly fired it can be machined then post fired for strength.
-
42 minutes ago, Bill Kielb said:
Good catch! I think I read something about that here on Jan 27th?
The normal way is single SSR and add a definite purpose safety contactor feeding the SSR’s...
Of late Kiln manufactures have been adding standard 12v relays in front of each leg instead of the clunky contactor which ends up pretty economical and reasonably reliable as the relay turns on first (unloaded) and stays on - no mechanical cycling.
Matching fast fuses can protect the SSR from damage for top notch design. Most SSR manufactures tell you the rating not to exceed.
I use a back to back SCR block rated at 600 volts and 100 amps. I have had a few total shorts that blew my 100 Amp breakers but the SCRs were fine. I feed the SCRs with MOC3060 chip that is a zero crossing switch so have made a pretty indestructible SSW. In the very rare event that my SSW did short out my SiC element would raise kiln temps to cone20!! so I always watch temps and cones when getting near cone10 for glaze firing or 1800F for a bisque.. I have made some hardware that I fired to cone20 so I know it gets that hot.
-
On 2/2/2022 at 11:19 AM, cadenrank said:
Disregard this. After a checking again, they were both matching each other this time, and then when I gave the kiln some power to heat it up, they both got up to about the same point as well.
I did learn that the connectors I bought fit backwards or normally into my pyrometer, so I'll have to keep an eye on the negatives and positives when I plug into my pyrometer.I have accurate tc readings but every so often the reading gets lost so reads 32F and is only recovered if I run
kiln-controller again. Not a good omen for a reliable controller. Trying to trace why this occurs. It is not due, I feel, to mechanical connection problems as it happens with no movement. It could be the crappy pin to socket connections from gpio to breakout tc board. The pins on the Raspberry pi are smaller than standard pins. Soldering direct to the boards might be a more reliable method.
-
23 minutes ago, neilestrick said:
It should work fine. Thermocouple connections don't affect the reading as long as there's no temperature difference across the connection, which there never is with small connector. That's why you can use standard terminal blocks for thermocouple connections, like most kiln companies do.
You can just connect them together . Paralleling the wires is fine. I use my Fluke in parallel with the max board so I can check them .
-
58 minutes ago, Mark Henshaw said:
Looking through my version of the code (downloaded Dec 2019, modified here and there since), the error likely stems from one of the following errors reported by the maxim chip: "No Connection" "Thermocouple short to ground" or "Thermocouple short to VCC." I've had problems with my setup where the TC leads connecting to the AdaFruit posts crossed (though this results in an erroneous reading, not a software exception). Perhaps re-check your connections and check that the TC is not grounding to the kiln frame?
regarding the IP address not working for you, this depends on your home network's local address and the specific address assigned to your PI. there are a couple of things to try if thats still not working for you. If you like, I can also dig up some python code I used to directly read and report the TC values on the PI screen to help localize the troubleshooting
The TC is in the open air so no accidental connection . It says Fail GND , VCC and ??? . I don't think much of the GPIO pins on my pi, they are smaller than I'd like. However the readout is always fine until the ERROR so I think it's software not hardware. I think you're right the Adafruit is reporting the ERROR so may be it is the problem. Changing to a simple max 55 board will at least change the scene...I'll keep you posted. (The 55 doesn't come until Monday 31st.)
Much Thanks
Ronald.
-
2 hours ago, MarkTilles said:
Rondoc, i have a working ISO image of 7.5 GB card I can share with you on MS OneDrive. It’s set up with a Pi zero w and max31856 if you might want to give it a whirl?
(But I can’t get to it until next week, need to change passwords etc first). Send me your email address if you’d like to give it a try
That's very kind of you. I am going to try a max 55 board and see if that works. The fail is something to with the way oven checks the TC output. It might also need a pi4B not the 3B I have now. My email is rdoctorsAaagmail.com and it would be easier for me for us to communicate via emails.
The pi 4 are expensive right now so I'll wait..May be just the zero is all I need. It will be dedicated to the kiln . Thanks.Ronald
-
On 11/28/2018 at 12:13 PM, jbruce said:
I got tired with going down to the basement to make sure my kiln was working properly and running on schedule so I started (forked) a project to control my KS-1018 using a raspberry pi. With this I can:
- monitor my kiln from anywhere using any device that has a web browser (phone/tablet/computer)
- easily create new schedules, edit existing schedules, including infinite ramps & soaks
- accurate PID control
- get schedule cost estimates and actuals
If anyone is interested, here is the github link... https://github.com/jbruce12000/kiln-controller
The cost for everything I bought was under $200.00, but my time investment has been high. Again, this is for geeks that were born with a soldering iron in one hand.
I have followed instruction on github site and it works until I get this "ERROR oven : problem reading temp N/C etc etc..implying I have lost the maximum adafruit module and it hasn't changed.
However until I get to this in terminal. I readout temp fine after 0.0.0.0.:8081..the TC is fine and checked by a Fluke all the time. This is repeatable. Help please.
-
12 hours ago, silfrsmithr said:
I got rid of the breakout board and wired directly pin to pin. Same results. I think I I'm going to have to wait for my '55 thermocouple interface to get here before I spend any more time on this. When I get that board in, I'll set the whole system back up but for that board and I'll post my results back here.
Once again, my thanks to any and all who have contributed on this project, and especially those who have helped me directly.
I think changing to the 55 chip makes sense. I will keep trying with the adafruit breakout board..funny it show correct temp for a second before going back to 32F. I'd love to know why this is happening.
Ron.
-
5 hours ago, cadenrank said:
This is a thread I've been lurking on for a while, and just yesterday decided to order some parts to try some things out. My goal is to use it as a way to monitor the thermocouple remotely temporarily, but eventually plan to turn it a full controller as well.
My question is that I noticed that the thermocouple amplifiers listed in the original github file say Max31856, and Max31855. I can see the pinouts are different between them. I ordered the 31856 because it was one of the only ones in stock. I read a few times in here about there being differences and issues with using one or the other, and am wondering what is needed differently from the original instructions to utilize the 31856. All of the diagrams I see for it show the pinout for 31855, and while I can gather which ones are the corresponding ones, it seems like maybe there needs to be changes in code or something? Like I said, I don't have any of these parts yet besides the pi and the type K thermocouple. I plan to follow the instructions as they were written (mostly because this is the first of this kind of project I've ever done) but want to know if I'm expecting to change something with the use of the 31856 board.I have the 32856 adafruit breakout boards. The software by Jason does cover the pinout and also uses the 31856 library from adafruit. In theory it should all work. In the config.py file you need to change thermocople to K and also change selection of board , it is 0 for the 56 and 1 for the 55 so you need to reverse those. Also the pinout is specified there being 4 GPIO PINS IN USE. the 3.3 volts from the pi goes to the Vin on the breakout board. Ground to any GND . It all worked when I first set it up and the profile system for heating is very clever...overkill for a pottery kiln as it was designed for a reflow soldering station but should be ok. Now for unknown reasons the temperature reading is screwed up. Not sure why but hopefully will be fixed very soon. I plan to use the system for monitoring until I feel it is solid..don't have that feeling yet! Let us know how it all works for you..together we can succeed. Ron.
-
4 hours ago, rondoc said:
Interesting I have same setup and I only get 32F and stuck for temperature , even after a reboot. This same with 2 of adafruit boards. I am now starting from scratch...new format on SD CARD.
and following Jason completely.
I wonder if the GPIO is somehow setup wrong. I tried the GPIO TEST that Jason gives to view all the pins but it didn't run on my raspberry. 3B only the 4. All a bit frustrating almost as bad as learning to throw many moons ago.
I have reinstalled rasping an followed Jason's info but still not reading correctly. It is stuck at 32F. It's also not loading from 0.0.0.0:8081. I might have a bad pi so that's my next step. I thought this was going to be easy....problem is with so much of the software it is very hard to trace a failure .
On the github info from Jason it says for local use 127.0.0.0:8081 but I have no idea what this gets me as nothing happens .what is supposed to happen ?
-
1 hour ago, silfrsmithr said:
Still no go. I think I have this wired the same as yours. I also order a MAX81355, but it's going to take a minute to get here.
Interesting I have same setup and I only get 32F and stuck for temperature , even after a reboot. This same with 2 of adafruit boards. I am now starting from scratch...new format on SD CARD.
and following Jason completely.
I wonder if the GPIO is somehow setup wrong. I tried the GPIO TEST that Jason gives to view all the pins but it didn't run on my raspberry. 3B only the 4. All a bit frustrating almost as bad as learning to throw many moons ago.
-
Off topic...If you use AC for your door lock it will buzz. I had one and to get rid of buzzing I rectified the AC and added a capacitor to smooth out the ripples. Nice and quiet now.
-
I thought my max31856 board was dead so got a new one and it is same. I am not sure that the pinout to the GPIO is critical if the same pinout is on the config.py but this am I am going to revert to Jason's pinout that is not the same as adafruit. May be it was for the 55 board so he kept it and just added the extra pin that the 56 needs. It is an enormous pity that with all the work that went into Jason's project a commercial version that is plug and play wasn't put out. I would be ok about paying for this, although most of the work was pro bono it still needs work for a commercial product.
If I can get my set to work I will use it as a monitor until I see how reliable it is. My kiln is in my garage and not next to my inflammable! I have found with my incremental power arrangement I only need to change settings every 30 minutes due the thermal inertia and great insulation.
-
Way off like real temp 80 readout can be 140 ..it behaves as though the sensitivity to temp is much higher. The reading does not jump about just is wrong. I have a Fluke digital thermometer on same thermocouple for checking.
-
On 1/19/2022 at 1:28 AM, newps said:
Hi,
the Adafruit 3263 uses the Max31856 chip, which in their infinite wisdom Adafruit have deprecated the Adafruit_GPIO software module, to introduce their Blinka software module. That would require quite a large rewrite of the code. see this link https://github.com/jbruce12000/kiln-controller/issues/55
I have been using the same Adafruit chip for a while and used an earlier version of this program, but I had to find my own software module for the Max 31856. I recently tried upgrading to the newest version of the RPi OS and of the kiln software and it wouldn't run. No error messages or anything on the screen when I tried to connect to the Pi. I am using one of the early Pi model B (GPIO pinouts are slightly different)
I have gone back to the Buster version of RPiOS and my old code and it appears to be working.
I did have the temperature reading correctly but now it's way I'm using the adafruit 86 breakout board and using the 3.3 volt input.. I noticed that even when it was working if the thermocouple is disconnected the reading jumps to 32 and then when reconnected it just stays at 32. I don't have another 86 board to try but have ordered one to see of problem with board , the pi model 3B or the software...thoughts on this anyone?
-
-
Thanks. I will try that. I just kept entering the ip not realizing I needed to add the 8081. I feel really stupid not to have tried that.. I'll report back soon.
Thanks.
-
55 minutes ago, newps said:
I assume that when you say it works fine on local ras.pi you mean that you can control it from a keyboard, mouse and screen attached to the actual RasPi.
To work remotely you need to know the local IP address of the Pi .
Heres how to do that
If you have a Raspberry Pi OS with Desktop installed on your Pi, you can easily find your Pi's IP address by hovering your mouse over the network icon (two arrows) in the top-right corner, next to the clock. An information panel will appear showing your Raspberry Pi's network connections.
Mine is on a ethernet link and comes up with eth0: configured 192.168.0.199
To remotely access the pi from a web browser on another computer/phone/tablet the other device must be on the same network as the Pi and you just type i the appropriate local IP address into the browsers address bar. So in my case i put in http://192.168.0.199:8081 and it comes back with http://192.168.0.199:8081/picoreflow/index.html in the address and the display below.
-
On 11/28/2018 at 12:13 PM, jbruce said:
I got tired with going down to the basement to make sure my kiln was working properly and running on schedule so I started (forked) a project to control my KS-1018 using a raspberry pi. With this I can:
- monitor my kiln from anywhere using any device that has a web browser (phone/tablet/computer)
- easily create new schedules, edit existing schedules, including infinite ramps & soaks
- accurate PID control
- get schedule cost estimates and actuals
If anyone is interested, here is the github link... https://github.com/jbruce12000/kiln-controller
The cost for everything I bought was under $200.00, but my time investment has been high. Again, this is for geeks that were born with a soldering iron in one hand.
Great job. It works fine on local ras.pi but how do I get to use it remotely...I have tried everything I know but nothing works for me. I am not a coder an old EE...HELP!!
-
I am trying to set up the Raspberry pi control and have installed software as per the github info. How do I get to see a display now .. any help please.. I am an old EE so probably missed something . I am using a Raspberry pi 3 B. with a Adafruit 3263 thermocouple board. thank you. ronald.
Geeks only - Raspberry PI controlled kiln
in Equipment Use and Repair
Posted
A problem might exist using a SSW that might be because not all SSW are zero crossing . This means that they will switch on whenever the pi says to go on. A zero crossing SSW will go on the next time the 60 cycles goes to a zero voltage AND the pi says ON. By switching at zero crossing the electrical noise is much reduced. That is also why relays are noisy because they switch on at any time the pi says go on. Relay contacts do also bounce giving intermittent sparking and much electrical noise. Relays can useful like cutting when off power with over temp. but not for a PID controller like the pi.