US Roaster Corp Sample Roaster - Thermocouple placement advice

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

#1: Post by shane_carlson »

Hey there. Been a lurker here in the forums for years and dabbled in home roasting off an on for the last 10.

Recently decided to step up my game and came across a great deal on a used US Roaster Corp Sample roaster that I could not pass up. Have cleaned up and am looking to add a couple RTD probes and a Phidget setup to monitor and log roasts via Artisan.

The one issue I have is deciding where best to add the BT and ET probes. Based on other threads here, I think I will add the ET probe to the bean chute where the existing analog gauge is and my initial thoughts on the BT probe would be just above the sight glass but wanted to check in to see if others with this roaster have experimented and found the best spot.





Here is the phidget setup I plan to install.

Vint Hub
2 Vint RTD phidgets
2 PT1000 4-Wire RTD

Will be running artisan on a dedicated raspberry pi touch screen mounted to the roaster.

Would love any advice and feedback from those who have already been down this path.

Thanks.

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mkane
Supporter ♡

#2: Post by mkane »

Looks to me like where they're at now is the correct position. Above the sight glass, the probe will catch lots of air.

Milligan

#3: Post by Milligan »

I agree, keep them where they are. That's pretty much identical placement as my 5 kilo USRC.

shane_carlson (original poster)

#4: Post by shane_carlson (original poster) »

Thanks. Been reading up on your 5K USRC journey. Very impressive.

I did see you jumpered the probes from the phidget to the factory PID.

This was one of the concerns I had and part of the reason I was going to leave those in place and add new probes for artisan, but that leave very few good options for placement. Seems you have had good luck with this setup. Any details you can share on how you wired them?

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baldheadracing
Team HB

#5: Post by baldheadracing »

shane_carlson wrote:I did see you jumpered the probes from the phidget to the factory PID.

This was one of the concerns I had and part of the reason I was going to leave those in place and add new probes for artisan, but that leave very few good options for placement. Seems you have had good luck with this setup. Any details you can share on how you wired them?
Feeding one thermocouple to multiple devices is not good except under specific circumstances, as given in: Splicing Thermocouple to PID and Phidget .
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

Moxiechef

#6: Post by Moxiechef »

I used to have one. I changed the factory PID probe to an Omega dual probe. Ran one back to the factory PID and one to my phidget.

shane_carlson (original poster)

#7: Post by shane_carlson (original poster) »

Definitely aware of the recommendations and the impedance issues, but I saw @MIlligan was doing it and curious about his results.


I decided I was going to use the existing BT probe location as the new RTD probe location. The swap the factory ET probe for the factory BT probe and move both the factory ET and the RTD Probe to the bean chute and measure ET for both inside the top of the barrell. The RTDs will feed the Phidget and the factory probes will feed the PID. No crossover.

I

shane_carlson (original poster)

#8: Post by shane_carlson (original poster) »

That sight glass ring was a PITA to drill and tap and it was a tight fit with the bigger 1/8 NPT mounting nut, but it cleared.

Milligan

#9: Post by Milligan »

Ive done several test runs and haven't run into any issues so far with the single probe feeding the PID and phidget. Artisan usually shows within a few degrees F of what the PID shows. Not sure of the sample rate on the PID so hard to compare directly. The only thing I needed to do was change the PID to read K-type instead of J-type. I'll certainly update my thread if I have any issues arise. I figured I'd try it and if it didn't work then I'd do a separate thermo or look into the dual leads.

Temp magnitudes seem correct as well. I'm hitting 1C within reasonable display temps.

shane_carlson (original poster)

#10: Post by shane_carlson (original poster) »

Alright.

Probes in place and wired up and showing working temps in artisan.

Will do a test fire tomorrow am when it isn't 101F out.