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Change of conditions when changing the roasting input weight
Yasu
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Posted on 12/27/2024 2:46 AM
Until now, we have been using lamp soak to feed back BT and change the profile of combustion gas temperature when conditions change, such as bean type, input weight, moisture content, and so on.
However, I would like to share the past data that I was able to keep the BT exactly the same even when the input weight was changed by controlling the exhaust gas temperature using lamp soak.

The flow of this control is
1. create a profile of exhaust temperature by lamp soak in the temperature regulator with the exhaust temperature as PV
2. Take the MV value of the control signal 0-100% after PID of the temperature regulator for the exhaust temperature as an external signal to the temperature regulator for combustion.
3. The combustion temperature regulator controls the combustion by PID control based on the remote SP value and outputs 4-20mA to the propane gas control valve.
The combustion was controlled by outputting 4-20 mA to the propane gas control valve.
We did the so-called cascade control.

４．As a result, the exhaust temperature remained within the profile by automatically calculating that the exhaust temperature did not increase with the change in input weight and increasing the amount of combustion gas to maintain the exhaust temperature profile.

5. The final target value of BT also remained exactly the same.

6. The coffee was roasted without touching the roasting machine during this period, and of course the taste of the finished coffee was exactly the same.

g: 1.6 kg c: 0.8 kg
IT = Air temperature after combustion
Yasu attached the following image:
800gvs1600g_.png
Edited by Yasu on 12/27/2024 2:53 AM
 
Yasu
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Posted on 12/27/2024 5:28 PM
What you need to see is
BTg and BTc
ETg and ETc
are two lines, but they overlap each other and reproduce as if they were a single line.
The IT (combustion temperature) is completely different because of this.
I have been trying very hard to create a combustion temperature profile, but to no avail.
 
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