New thermocouple setup/ first time Phidget-ing

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

#1: Post by debadano »

Hello Home-Barista people.

i've been snooping these forum's for a couple years but finally am posting for the first time.

I am roasting on an Ambex YM-2 from 2004 with a Watlow SD PID and it had a Type-J Thermocouple in it when I bought it and an analog thermometer in the hopper chute (for lack of better term)

i have been logging roasting data with a notebook and pen for 2 years. bought a phidget vint hub with tmp1101_0

i recently replaced the thermocouple with a type k 2mmx60mm and put a type k 3mmx45mm in the place of the analog thermometer.

i am getting very wonky temperature data.

the number on my digital readout on my watlow PID is about 40 degrees higher than the readout in artisan. and they all seem very low from what i am used to with my other type j.

also interesting. is until i drop beans in, all the numbers are very similar. the BT and ET are almost the same number and the artisan data is congruent with the watlow readout. drop the beans in and the numbers start to drift apart.

i changed the TC lineation from type j to k in the watlow settings.

any ideas would be greatly appreciated.

thanks!
Devin
Lake Wind Coffee

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CarefreeBuzzBuzz

#2: Post by CarefreeBuzzBuzz »

2mm is often subject to wide swings. The PID has what probe. Now they are different and you can expect them to read differently.

Have you read On Idle Noise on the Artisan Blog?

If you decide to change these out, the most common recommendation of late is a 3mm RTD. Again see the blog post.

Good luck.
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MaKoMo

#3: Post by MaKoMo »

debadano wrote: I am roasting on an Ambex YM-2 from 2004 with a Watlow SD PID and it had a Type-J Thermocouple in it when I bought it and an analog thermometer in the hopper chute (for lack of better term)

i have been logging roasting data with a notebook and pen for 2 years. bought a phidget vint hub with tmp1101_0

i recently replaced the thermocouple with a type k 2mmx60mm and put a type k 3mmx45mm in the place of the analog thermometer.
Note that the k-type TC are different to your original j-type TCs. You need to adjust the settings in the Watlow to adjust for the different (non-linear) temperature to voltage curves. Also in Artisan you need to adjust the TC type in your Phidgets tab to get correct readouts.

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Brewzologist
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#4: Post by Brewzologist »

Devin; Can you post a picture of where the TC's enter the faceplate of the roaster? (TC location affects readings). Also, your profile didn't post earlier, so if you can re-share it that would be great.

debadano (original poster)

#5: Post by debadano (original poster) »

yeah i changed the settings in the watlow for type K and the settings in artisan are set to type k for both probes.






debadano (original poster)

#6: Post by debadano (original poster) »

what do you mean about the non linear voltage curve?

debadano (original poster)

#7: Post by debadano (original poster) »




i took all 3 of these pictures within a second or 2.

the digital readout is coming from BT 2mmx60mm type k probe i have a type k thermocouple extension wire jammed into the same holes in the pid as the thermocouple itself and then into the phidget tmp1101_0

the analog thermometer is shoved into the trier hole

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debadano (original poster)

#8: Post by debadano (original poster) »


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MaKoMo

#9: Post by MaKoMo »

debadano wrote:what do you mean about the non linear voltage curve?
See WikiPedia on Thermocouple and especially the chart showing the characteristic functions of the different TC types.

debadano (original poster)

#10: Post by debadano (original poster) »

so if i read this whole wikipedia article, should that help me figure out how to configure my PID do you think?