# Amazon Dalian - ET reading



## filthynines (May 2, 2016)

I have another post to follow because I'm pulling my hair out. But I've just re-read something that @frederic very helpfully wrote in response to some queries I had at the start of the year.

https://www.coffeeforums.co.uk/topic/48344-artisanroastlogger-and-amazon-dalian/?do=embed

He uses the right side hole at the front as ET for the purposes of Artisan. I thought ET should be the same as air temp, and I understood that @Hasi accordingly replaced the sensor at the rear with an RTD and hooked it up to the Ewelly and Artisan. (I could be wrong on that.)

So, quite simply: from where on the Amazon Dalian should I be taking the ET reading?


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## Rob1 (Apr 9, 2015)

I would have thought ET should be taken from in the drum away from the bean mass?


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## filthynines (May 2, 2016)

Rob1 said:


> I would have thought ET should be taken from in the drum away from the bean mass?


 That seems right to me, which would mean the rear of the machine (which is where the exhaust is).


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## CJV8 (Apr 8, 2019)

filthynines said:


> That seems right to me, which would mean the rear of the machine (which is where the exhaust is).


 Does it need to be the rear? If you think how slowly the trier (or at any rate mine...) fills, could the factory fitted K-type probe position be considered sufficiently outside the bean mass to be used for the ET? That's my loose plan, although I haven't enacted it yet so it's just theory.🙄


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## Rob1 (Apr 9, 2015)

I thought they were both on the front. BT near the trier, ET to the left hand side? I assumed there were depth differences but looking at the review they're both bean mass probes and ET is taken from the back. Outside the perforated roasting drum, between heating elements. Makes sense really. You avoid the bean mass entirely but still get an accurate ET within the roasting drum because it's perforated.


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## filthynines (May 2, 2016)

Rob1 said:


> I thought they were both on the front. BT near the trier, ET to the left hand side?





CJV8 said:


> Does it need to be the rear? If you think how slowly the trier (or at any rate mine...) fills, could the factory fitted K-type probe position be considered sufficiently outside the bean mass to be used for the ET? That's my loose plan, although I haven't enacted it yet so it's just theory.🙄


 Honestly, I don't know. I'm starting to think this is the case though. It's something new for me to try tomorrow - I will definitely report back. You've both suggested the opposite way round to each other. The left side is closer to the sight glass, so closer to the beans..? I don't know...

Thanks chaps!

Keep the suggestions coming, all ye who pass through here.


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## CJV8 (Apr 8, 2019)

Mine's set so the BT is left hand most probe on the front panel, the K-type immediately adjacent to the trier isn't used as standard.

I'm not sure of the panel thickness at the rear of the drum where the ET PT100 is, maybe @DavecUKcould advise on the thickness? I don't know if it's as thick as the front panel so it may be easy(ish) to add a second ET probe for Artisan if you didn't want to go down the dual output PT100 route?

Edited as my phone had 'a moment', switched to the laptop...


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## filthynines (May 2, 2016)

CJV8 said:


> Mine's set so the BT is left hand most probe on the front panel...


 So that's what I've been plugging into Artisan. I've taken the rear PT100 that was hooked up to the "Air Temperature" Ewelly, moved it to that hole, and I've re-wired it to a temperature sensor and then into my computer via USB. Trouble is, its readings aren't making much sense. Not getting that "swoosh" on the roast curve.

I think you told me elsewhere that you bought a PT100 from TC Direct, am I remembering correctly? Or am I misremembering? And are you using Artisan too?


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## CJV8 (Apr 8, 2019)

filthynines said:


> I think you told me elsewhere that you bought a PT100 from TC Direct, am I remembering correctly? Or am I misremembering? And are you using Artisan too?


 That must be someone else, I've not made any mods to the probes. Was it @Hasi?

I've only just downloaded Artisan to play around.


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## RDC8 (Dec 6, 2016)

A quick question on the ET probe reading. When the drum is empty, ie before it is charged, should the BT and ET probes be showing similar temperatures? In my mind they should be as they are both measuring the same thing at that stage - the hot air inside the drum. Yet I can be showing a temperature differential of 40-60 centigrade (ET being the higher measure)

I'm measuring ET via a 3mm K-type probe which goes into the drum via the hole on the front-right where the spare factory-fitted 5mm probe was placed. The BT probe, also a 3mm K-type, is going through the lower sight-glass bolt hole.

Any reason why they are not giving the same temperature reading for an empty drum?


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## CJV8 (Apr 8, 2019)

RDC8 said:


> Any reason why they are not giving the same temperature reading for an empty drum?


 I get the same thing. The ET probe is sitting closer to the heating element, so in steady(ish) state conditions with limited airflow, and the same probe type and size you'd expect it to read a higher temperature.


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## RDC8 (Dec 6, 2016)

Ahhh -that makes sense.

I'll take a reading from a cold drum before I roast next time; the two temp reading should be identical at that stage.

TBH - I don't normally turn artisan "on" at the start of a session until I am getting close to charging the first batch.

Thanks


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