Help Getting Started with PID and Artisan

Discuss roast levels and profiles for espresso, equipment for roasting coffee.

#1: Post by ontum »


I just picked up a Toper Cafemino 1kg electric coffee roaster and it only has one temp probe for ET.

I would like to set up a BT probe and used a Delta DTb4848V1and SSR and control it with Artisan. I would also like the ET to be logged in Artisan.
Can you all help me with the logistics?

1. Do I need 2 PIDs? One for BT and one or ET (one only to be logged and viewed)? If I need a second device to do this I would rather use a second PID.
2. How do I connect the PID to the computer? I found info on the Fuji, but not the delta.
3. How would I connect two PIDs to be viewed/logged?
4. Which probes and from where to purchase? RTD seems more accurate and lower temps, but most people talk about K type.

Thank you very much for your help.

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#2: Post by happycat » replying to ontum »

1. No. BT and ET relate to two diff locations of temp measurement inside the roaster. The PID controls your heater. One heater, one PID.
2. You can use Artisan to provide software PID (or use hardware instead if you prefer)
3. Not sure why you would have 2. You just need one probe per measurement and a device to turn that probe's results into something your computer can understand (like a Phidget 1048)
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ontum (original poster)

#3: Post by ontum (original poster) »

Thank you for the help.

Here is my line of thinking. Please let me know if I'm off base.
1. I would like a PID to monitor and control the heat from BT. (PID 1)
2. I would like to use that PID to be controlled by Artisan, but has the capability to used stand alone if needed. (PID 1)
3. I believe the PID only has one input, so I need a second device to monitor and the ET and be logged through it in Artisan. So I figured I could use a second PID for this.(PID2) It just would be nice to use the same device to monitor the ET, even though it wouldn't use an output. Or is there a better way?


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#4: Post by happycat » replying to ontum »

1. Sure. Choosing ET/MET might be better though. You can set a ceiling ET target and keep it pretty steady through the roast and lower the target based on changes in BT [eg. When BT gets close to first crack around 390f you might lower the ET target temp for the PID because the beans are going to go exothermic)

2. Ok. There are probably other HB members who have standalone PIDs. I implemented one on a TC4/Orange Pi using roastlogger. I don't think tc4 is sold anymore. The orange Pi works over wifi but was slow. I stop using it because I dropped it and it stopped working so I went back to my old MacBook

3. You don't need a separate "PID" to monitor each input. My Tc4 supports 4 thermocouples. So I have roastlogger graph BT and ET and I run my PID software in roastlogger based on the ET.
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#5: Post by drgary »

This thread may be useful to you. It appears that the OP is using PID to control a steadily declining rate of rise.

Roasting with PID

What I WOULD do for a good cup of coffee!

Wiz Kalita

#6: Post by Wiz Kalita »

4. RTDs are superior to thermocouples in terms of accuracy and repeatability. The disadvantage is that the element is fragile and needs a thicker protective capsule if it's going to be in a rough environment like a BT probe, at least a few mm. So if you want very fast response times, a thermocouple is the way to go. Also you'd need a controller that supports RTDs, but I think yours does.

ontum (original poster)

#7: Post by ontum (original poster) »

Hello, thank you all for the replies.

I have come up with a plan on hardware but I am a rookie when it comes to these things, so please let me know if something is off.

I purchased...
This 3mm x 50mm RTD probe for the BT.
This 5mm x 50mm RTD probe for the ET

Two of these Delta PIDs DTA4848V1 that should allow PID control from Artisan
Two of these USB to RS485 Converters to connect the PIDs to the computer.

The Delta PIDs can use K type thermocouples as well, if I'm not happy with the RTDs.

Anyone have any advise?

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#8: Post by Marcje »

I also have a 1kg electrical Toper Cafemino and installed a 'Duplex' thermocouple (j-type).
It's basically the same thermocouple as the one the Cafemino already has, but it has two connectors: One end goes into the electrical system of the Cafemino (as the original one), and the other connector can be used as input for Artisan (via a thermometer like the Mastech ms6514, or a Voltcraft PL-125-T4USB).

I have not installed a PID (yet), but by using this type of thermocouple, I at least have no temperature offset between what the Cafemino measures, and what Artisan displays. That already helps a lot.
I seriously wonder if it makes sense to use a PID on the Cafemino, but I will follow your topic over here with great interest, good luck!

Edit: Btw, do you happen to have an electrical diagram of the Cafemino? I don't, but that would certainly help a lot with PID-ing the roaster...

ontum (original poster)

#9: Post by ontum (original poster) » replying to Marcje »

Thanks for the input. I do not have a diagram for the roaster, but I opened it up and it looks pretty straight forward. I will let you know how the wiring goes. I've added a BT temperature probe, but sadly dont have a way to monitor it yet. I'm still waiting the PIDs from a slow boat from China.

I'm still not sure at what temperatures to roast on this machine. Anyone have a simple starting point of temperatures for this machine?
I've done three batches so far.
1. Drop 10 200°C with 800 grams. 1/3 open air vent. Full heat until FC. FUll open air for a couple minutes then drop.
2. Similar but tried dropping at 210°C

3. Worst roast yet - Drop at 180°C, 800 grams. Vent opend 25% for 3 minute, then closed until FC. Temperature bottomed out at 160°C and never got it above 161°C until FC when I opened the air all the way at 10 minutes in.

These temps are ET an the proble looks very old, so I'm not sure accurate it is. Any advise on this machine for what temperatures I should be aiming for on the ET while roasting?

Thank you for the help,

This is where I've added the BT

ontum (original poster)

#10: Post by ontum (original poster) »


I would like to be able to vary the fan speed and drum speed of the roaster.

I've never used a a VFD before. Can I just install a VFD like this for each motor and hook them up to Artisan through the RS485 I will be running for the PIDs?