rondoc

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.

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. )

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.

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.

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.

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 .

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.

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

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.

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.

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.

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 ?

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.

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?

So simple...yes it worked from my cell phone....now I can get on with pottery... thanks so so much.

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.

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.