Sliders and offsets in Artisan
Michael Herbert is working on a beautiful online manual for Artisan users, entitled Artisan Getting Started Guide - Coffee Roasting -- a web page with the link to a PDF of the manual.
He emailed me asking if I could clarify something:
You may have a set of sliders like mine here on the left in the illustrations below:
In principle, the slider for FAN could be used from 0% (OFF) to 100% (MAX speed).
See for example https://artisan-roasterscope.blogspot.nl/2016/08/fz-94-4-taking-control.html with this illustration where the slider ranges from 0-100 and the effect is also 0-100%:
But that would mean we could only use part of the slider range productively, since during roasting, the slider would be in my case on 33% as a minimum, to ensure the heating elements will always be able to release their energy without overheating, and to have a minimum of airflow through the bean mass at all times preventing a 'smoky' aroma in the output of beans. So 0% on the slider actually equals 33% of airflow capacity, and 99% of slider corresponds to 99% of airflow capacity.
See the middle column in the example card below (I believe those are not the exact numbers I use today but it's an illustration taken from an earlier blog).
Therefore, in the slider setup menu, I have entered the numbers to get this result:
You may wonder how I found the values for "Offset" and "Factor".
Marko Luther made me a simple little spreadsheet to get these values:
This spreadsheet is available here:
He emailed me asking if I could clarify something:
"There are mysteries in many of the dialog boxes. For example what are the Offset and Factor for in the Events dialog > Sliders Tab.So here goes!
If you have a good written reference on the automation features that you can point me too that would be useful."
You may have a set of sliders like mine here on the left in the illustrations below:
 |
| Roast profile with sliders on the left |
See for example https://artisan-roasterscope.blogspot.nl/2016/08/fz-94-4-taking-control.html with this illustration where the slider ranges from 0-100 and the effect is also 0-100%:
But that would mean we could only use part of the slider range productively, since during roasting, the slider would be in my case on 33% as a minimum, to ensure the heating elements will always be able to release their energy without overheating, and to have a minimum of airflow through the bean mass at all times preventing a 'smoky' aroma in the output of beans. So 0% on the slider actually equals 33% of airflow capacity, and 99% of slider corresponds to 99% of airflow capacity.
See the middle column in the example card below (I believe those are not the exact numbers I use today but it's an illustration taken from an earlier blog).
 |
| Example of a possible conversion card of sliders and capacity of drum speed, fan speed, heater power/duty |
 |
| Note: disregard the "command" entry as this may very well be different for your roaster. |
You may wonder how I found the values for "Offset" and "Factor".
Marko Luther made me a simple little spreadsheet to get these values:
 |
| Slider values spreadsheet |
You can disregard the example text on the left. If you want to spread 0-100% of the slider over 40-70% of the capacity, you enter those numbers as 4000 and 7000 under the 0-100 fields and to the right of that you read the values for Factor and Offset.
PS Jan van der Weel wrote:
I just looked at Frans his post and now I understand how it works : )
I just looked at Frans his post and now I understand how it works : )
The file creates a lineair line between:
Source (input of slider) - Output control (Desired values)
0 4000
100 7000
The calculation of all the control points is done by a linear equation that's calculated in Frans his file.
Source* factor + offset
Source * 30 + 4000
example = (0 *30) + 4000 = 4000
(100*30) + 4000 = 7000
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