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Skywalker roaster mods
Bill grubbe
Top  #376 Print Post
Posted on 07/26/2024 8:23 PM
I just plugged in my computer into the USB port to start use artisan and the transformer blow on the roaster now everything works put the 240 v part of the roaster so I put in a new transformer and it blow to I think I have a low voltage short somewhere anybody has any thoughts about this it would be very appreciated
 
Dan N
Top  #377 Print Post
Posted on 07/27/2024 7:39 AM

Quote

Robotic Kitten wrote:

BTW, decided to build me a replacement board, based on F412 MCU.
Doh, why it wouldn't let me attach a .jpg or .png
https://1drv.ms/i...w?e=sjmXzZ

That is VERY impressive. Any feature upgrades (thermocouple support, etc)? How's the software progress?
 
renatoa
Top  #378 Print Post
Posted on 07/27/2024 12:43 PM

Quote

Bill grubbe wrote:

I just plugged in my computer into the USB port to start use artisan and the transformer blow on the roaster now everything works put the 240 v part of the roaster so I put in a new transformer and it blow to I think I have a low voltage short somewhere anybody has any thoughts about this it would be very appreciated


I would check the cable connections/order, for roaster and also the PC.
Already had bad experience with cables having wrong wire order.
 
billsey
Top  #379 Print Post
Posted on 07/28/2024 8:27 PM
Was the USB port on the computer plugged into the 'notUSB' port on the roaster, or did you plug it into the USB port on an Arduino running the control software for Artisan to use? Either way I can't see anything obvious that would blow a transformer on the roaster. If anything got blown from plugging it in it would be on the power that provided through that port, which is only 5V, or on the computer side of things.
 
renatoa
Top  #380 Print Post
Posted on 07/29/2024 1:29 AM
A wrong made cable can carry the mains line to the PC ground, and from there, via USB shield, into the roaster case.
 
HarryDog
Top  #381 Print Post
Posted on 08/05/2024 6:18 PM
Hello renatoa, I finally came back to implementing your Spy Temp Filter code into Skycommand. It looks to be running and the FILT: command in IDE reports changes.
Just some basic tests in Artisan all the Lamp, Fan, roaster look to work.
No roast yet but the temp looks to be smooth as I was testing 80% filter and 2 Second sample rate. Not sure how fast I should push this?

Anything else I should look at or test as time has gone on?
 
renatoa
Top  #382 Print Post
Posted on 08/06/2024 2:42 AM
It's ok as you set, but you can lower to 70%, for less delay of the reading.
80% is 4 readings delay, 70% is 2 readings.
Checking "Oversampling" is another way of filtering, equivalent to 50% filter, and available to any people, any measurement system.

Quote

Anything else I should look at or test as time has gone on?

The empty machine drive test, as I posted previous page?
 
HarryDog
Top  #383 Print Post
Posted on 08/06/2024 4:46 AM
Thanks will do some more testing later today.

I have also been playing with two Max chips, the Max 31855 K only type module and a probe I tested out side of the roaster worked fine but the one I have inside the roaster that was working with the Phidget does not work for some reason.

Thinking of using the IDE example with fault detection to see if I get some reason why its not working correctly? It does work if I plug it into my hand meter as well.
 
renatoa
Top  #384 Print Post
Posted on 08/06/2024 12:37 PM
What is the purpose of replacing actual temperature system with another performing at most on par ?
MAX: 0.25C resolution, 4 samples per second
NTC: 0.2C resolution, 9 samples per second.
 
HarryDog
Top  #385 Print Post
Posted on 08/06/2024 1:46 PM
Thanks, I'm not sure I ever read any specs on the original code but if using FILT 70% at 1 second sampling what resolution is the NTC at?

I think I see the issue with MAX31855K, once the Skywalker is powered on I get a short to ground fault on the probe. Is this just an issue with a grounded probe? I tried to ground the other probe to the same plate and it still worked. I have a number of K thermocouples that were purchased all over the place so no idea if grounded or not but assume most are? I should be able to test the continuity from the leads to the outer sheath.

At some point I would like to make a 1kg roaster of some type but unsure if I will get there or not.
 
renatoa
Top  #386 Print Post
Posted on 08/07/2024 4:58 AM
Filtering does not affect resolution (too much) For more resolution you need oversampling.
The main function for which I added the filtering was to smooth the spikes, rather than to increase the resolution.

Actually, for Skywalker the resolution is a very fuzzy concept.
The canonical approach is to divide measurement range by the values count.
Example: 250C measurement range, 10 bit ADC => 1024 values, resulting 0.25C degree per ADC step.

But Skywalker is using only partial the whole ADC range, for two distinct measurement ranges, as explained the previous page post.
Add to this design quirk the logarithmic nature of the NTC curve, and you have different resolutions along the whole range.
Analysis performed on the data gathered by josh, that was used to build the interpolation formula(s), reveals that we have at least 6 ADC values per C degree (i.e. 0,17C per ADC step resolution) in the range 30-180C, decreasing to 5 ADC values per C degree (i.e. 0,2C per ADC step) in the range 180-210C.

Two examples:
- the range from 145 to 155C, including 150C value, used by many people as the standard dry end, is encoded by the ADC values range from 610 to 671, thus 61 steps.
- the range from 175 to 195C, the most important for FC and development phase, is encoded ADC values from 379 to 490, thus 111 steps, for 20C range.
Edited by renatoa on 08/08/2024 2:27 AM
 
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