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Well holy crap that was rough
shortyjacobs
First roast on my artisan/arduino/tc4+ powered fluid air roaster.

Typically I'm around 3 minutes to tan, 4 minutes to FC, 4 minutes to start of second snaps and boom, Full City+ coffee.

For one, my first crack almost always was around 370-380 with my old setup. The new thermocouple is obviously different as my BT was much higher at FC. Also, I only heard one snap for FC, then nothing until all of a sudden tons of second crack snaps and I hurridly killed the heat. This blend I usually took to ~420 on my old roaster, the new thermocouple read ~480! (I likely took it ~10 deg too far). Also, clearly my probes are no where near calibrated, as ET reads lower than BT (yes, they are configured correctly).

20 minutes on the new setup vs a very consistent 12 minutes on the old setup. Same heater, same fan, just new controls. I've got a lot of learning to do. Any pointers???

i.imgur.com/9RmLFvP.png
i.imgur.com/ct7jFbM.jpg
-Keith
jbrux4
I've got a used heat gun and flour sifter you can use until you get it dialed in Roflmao

I feel that I will be going through these same trials when I start roasting on my new set-up - officially roasting, not the unofficial turn on the heat and see what happens roasting I've done.

I'm sure the experts will provide their take. However, I didn't quite understand the ~40, took it ~10 degrees too far statement. Did you try to hit ~470?

When I did my first roast, my ET was reading approximately 40F too low compared with a calibrated external k-type. Since then, it has corrected, but I don't know why. I did put the exposed junction further into the flow of the air. I have also added grounding to the set-up, as in grounding the outlets to the roaster. I've redone the cabling for the thermocouples as well because I have a bulkhead pass through now. Somewhere in there, something corrected the low temp I originally was receiving.
R/
Jared
pisanoal
A few questions and thoughts.

What is your heat source?

Did you intentionally limit your ET? It seems like you had plenty of room to push the ET and get a faster roast. Looks like you hit a max of 420ish? Hard to read on the plot you posted.

What are you controlling to? BT, ROR, or ET set point?

What is your sample interval set to? That ROR curve is all over the place. I was struggling with consistency on a manually operated roaster, slowed the sampling interval down and it made it a whole lot easier to control surprisingly. I thought i would lose too much data and i would be behind on making changes but it was just the opposite. Way easier to see what was going on. With an automated roaster, thise oscillations could cause a control nightmare. Alternatively you could apply some smoothing to your ROR curve if your sampling interval is already around 2 or 3 seconds.

Everything else the same, id question thermocouple placement and readings. Especially if you arent seeing 1c and 2c at similar temps as before (at least within 20 degrees)
shortyjacobs

Quote

jbrux4 wrote:

I've got a used heat gun and flour sifter you can use until you get it dialed in Roflmao

I feel that I will be going through these same trials when I start roasting on my new set-up - officially roasting, not the unofficial turn on the heat and see what happens roasting I've done.

I'm sure the experts will provide their take. However, I didn't quite understand the ~40, took it ~10 degrees too far statement. Did you try to hit ~470?

When I did my first roast, my ET was reading approximately 40F too low compared with a calibrated external k-type. Since then, it has corrected, but I don't know why. I did put the exposed junction further into the flow of the air. I have also added grounding to the set-up, as in grounding the outlets to the roaster. I've redone the cabling for the thermocouples as well because I have a bulkhead pass through now. Somewhere in there, something corrected the low temp I originally was receiving.


The comment on temps was becuase I didn't know what I was shooting for. My old thermocouple would read 420 when teh roast was done. I ran this roast to 480 before realizing i'd overshot and killing the heat, and from the looks of it I should have cut out about 10 deg cooler. I'm not sure why it's so different. I need to drop my TCs into some boiling water and ice water to see if they are reading right.

Quote

pisanoal wrote:

A few questions and thoughts.

What is your heat source?

Did you intentionally limit your ET? It seems like you had plenty of room to push the ET and get a faster roast. Looks like you hit a max of 420ish? Hard to read on the plot you posted.

What are you controlling to? BT, ROR, or ET set point?

What is your sample interval set to? That ROR curve is all over the place. I was struggling with consistency on a manually operated roaster, slowed the sampling interval down and it made it a whole lot easier to control surprisingly. I thought i would lose too much data and i would be behind on making changes but it was just the opposite. Way easier to see what was going on. With an automated roaster, thise oscillations could cause a control nightmare. Alternatively you could apply some smoothing to your ROR curve if your sampling interval is already around 2 or 3 seconds.

Everything else the same, id question thermocouple placement and readings. Especially if you arent seeing 1c and 2c at similar temps as before (at least within 20 degrees)


Heat Source is electric, here's a full overview from my other thread https://imgur.com/a/kTbWdyE.

Didn't intentionally limit my ET. It's an air roaster, so ET is kind of hard to run independently of BT. The ET hit a max of 420, with the BT hitting 480, which is impossible in an air roaster, so something else is going on. Either one or both probes is grossly mis-calibrated, or something like this https://www.scottrao.com/blog/be-care...-bean-data.

I ran this roast similar to how I ran em manually on my old setup. I got the fan going for a good spout, got a heater % that would give me a good beginning ROR, then slowly bumped the heater up until I hit 100%, then slowly dropped fan down to maintain a target(ish) ROR. Here's a bigger version of the graph: https://i.imgur.com/9RmLFvP.png.

Yah, Sample interval was down at 1 sec. Also, the Artisan filters were all dropped to 0% (still had the arduino filters at the aartisanQ_PID sketch defaults). The ROR curve was messy, but BT and ET were pretty smooth still, so if I'm controlling to BT I shouldn't have too much trouble, I'd hope? I dunno. I haven't gotten close to the automatic part yet.
-Keith
renatoa

Quote

shortyjacobs wrote:

It's an air roaster, so ET is kind of hard to run independently of BT. The ET hit a max of 420, with the BT hitting 480, which is impossible in an air roaster, so something else is going on. Either one or both probes is grossly mis-calibrated, or something like this https://www.scottrao.com/blog/be-care...-bean-data.


Do both probes show same temperature during preheat ?
I am puzzled about the "run independently" part... in an air roaster ET is what drives BT... always ! Never BT influence ET, even in the FC start phase, if this happens then airflow is not enough and is not a real pure convection roaster.
If not having a reliable BT reading, is preferable to roast based on ET, I did this for various roaster buids, and works very well. Start with 3-400F preheat, charge, keep there for one minute then ramp slowly to 480 by minute 4-6, keep there until FC, develop, and you have a good roast.
shortyjacobs

Quote

renatoa wrote:
Do both probes show same temperature during preheat ?
I am puzzled about the "run independently" part... in an air roaster ET is what drives BT... always ! Never BT influence ET, even in the FC start phase, if this happens then airflow is not enough and is not a real pure convection roaster.
If not having a reliable BT reading, is preferable to roast based on ET, I did this for various roaster buids, and works very well. Start with 3-400F preheat, charge, keep there for one minute then ramp slowly to 480 by minute 4-6, keep there until FC, develop, and you have a good roast.


Nope, ET lags and reads lower than BT during a preheat. Clearly something is hosed up with my TCs. I plan on getting at that soon. I'm going to remove the probe casing from the ET probe to expose the bare junction. I'm gonna replace my 5mm diameter BT probe with a 1.5mm BT probe. And I'm going to calibrate them at a few temps. Oddly enough they read the same at room temp - the difference only becomes more pronounced as temperature goes up.

By independently i meant I can't drive ET up or down without affecting BT, exactly as you said, ET drives BT. In the past, before I switched to these new thermocouples and the TC4/Artisan, I manually roasted with BT only, and it worked more or less fine. So this ET stuff is a bit new to me. Thansk for the advice on an ET profile, I'll have to try that, if only to see how BT tracks with it!
-Keith
renatoa
Ok, is understandable that when different sheathed, a probe lags against the other, but at fixed power the temperature must stabilize somewhere and both should read the same value, in the 2-3 degrees ballpark.
I would check if this happens, and if not, if there is an offset.
Finding the offset rule would be the new step...
shortyjacobs

Quote

renatoa wrote:

Ok, is understandable that when different sheathed, a probe lags against the other, but at fixed power the temperature must stabilize somewhere and both should read the same value, in the 2-3 degrees ballpark.
I would check if this happens, and if not, if there is an offset.
Finding the offset rule would be the new step...


Yup, I did let it stabilize and there was certainly a 30 plus degree offset. We’ll see what happens when I swap stuff around. Thanks!
-Keith
shortyjacobs
Well, one mystery solved. The colors on my “type K” BT thermocouple wires were red and blue. Checking reference tables, that indicates a type T thermocouple. Checking voltage tables, a type T thermocouple at 420F puts out as much voltage as a type K at 480F. (I had it as a type K in the firmware). So my BT really ended where it should have around 420-430, it was just an incorrect thermocouple saying it was at 480F. Guess you can’t trust random eBay sellers!
-Keith
renatoa
Funny, I have red and blue wired TC that I am sure they are K, and they quack as a K...
Seems wire codes are also depending on country:

https://www.thermometricscorp.com/Thermocouple_Color_Codes.html

Surely I never seen a yellow or green wire on any of my TC... as should be for certain countries K type probes.
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