Another Quest M3 PID modification

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

#1: Post by afan »

Reading a lot from HB and other forum about Quest M3 and PID modification, I have nearly completed my PID setup. Thx a lot for folks like Arpi another_jim for their posts and EricS help for some of the parts. Here are the photos of my setup.

1. I tried to make it modular so that it can operate manually without connect with the PID box.
2. All the high power electric wires are contained inside the roaster
3. Connection between PID box and Roaster are low power DC.
4. Data and control can be via USB cable or USB-RF module (computer can access the PID via RF)

I am still learning to use PID, right now I am only using SV and data logging.
How to do with Ramp and Soap?

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#2: Post by Carneiro »

So nice! Very professional!

I need to make a box for the Arduino + LCD and maybe a SSR box like yours, below the roaster, so I could use the PID software for the Arduino too.

But last days I had time just to roast. I'm in debt with the Artisan and Arduino TC4 team. :oops:


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#3: Post by another_jim »

Holy crap, that is professional. PIDs pretty much last forever and can be used in multiple apps, so building them in an external box is a good idea.

I haven't PIDed my Quest, but I have PIDed several air roasters. I prefer controlling the environmental temperature and letting the bean temperature follow whatever trajectory that induces. This prevents oscillations in the environmental temperature which when using a critically damped PID loop on the bean temperature. The alternative is more technical, but useful if you need very precise profiles, this is using a highly overdamped tuning of the PID on bean temperature. The easiest method is to let the autotuner do its thing, then to halve the power of all the constants (Fuji uses a span for P, so you will have to double that, and halve the I and D ones).

For the ramp and soak: For profiling bean temperature, use ramps only (soak times of zero) since you want the set point to be rising all the time. I use a four segment ramp for bean temperature: up to 200F in one minute, to 300F in 3 minutes, to 385F in 3 to 6 minutes, to roast finish in 3 to 5 minutes. The first two segments are for drying. The final two segments are the roast proper, the 3rd is the ramp to just ahead of the 1st crack (which starts at 3895 on this scheme (calibrate the numbers if your sensor gives different readings) . keep the total length of the two segments at around 7 to 9 minutes and trade off. A long ramp to the first and a quick finish is the Diedrich's profile which favors more savory malty/woody roast flavors, while a short ramp to the first and a slower finish favors sweeter caramel/chocolate roast flavors.

I don't get a lot of enthusiasm for Diedrich's profiles on espresso, but it does amazing things for the occasional brew coffee.
Jim Schulman

afan (original poster)

#4: Post by afan (original poster) »

Márcio, Looking forward to see your toys
Jim, thx for the advice, will try and see.

Here's the photos inside the boxes and the spaghetti.

The 220-->5V power supply is only for the RS485 to RF module

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#5: Post by Arpi »

Nice looking setup. Congrats.


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#6: Post by afan (original poster) »

This wiring diagram is for reference or research use only, it is not recommended to built anything base on this diagram.

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#7: Post by tiga »

Your setup is very nice!!
I would like to ask how could you use two PID to control one SSR? Thx!!


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#8: Post by afan (original poster) »

I use both for data logging and only one PID for controlling MET.
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#9: Post by afan (original poster) »

Just tried TC-4 borrowed from a friend. With TC-4, I can log and plot BT, ET and MET in real time (Though I think 2 are already sufficient practically) and control the heat power by the Artisan Software. It is great!. The next modification will be the Fan speed control which could be a bit difficult since the Fan inside Quest M3 is A/C type. It would be great if the Artisan can incorporate PID functions (multiple input) and auto trigger event.

Thx a lot for both the TC-4 and Artisan team !!!
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#10: Post by JimG »

afan wrote:The next modification will be the Fan speed control which could be a bit difficult since the Fan inside Quest M3 is A/C type.
Might not be so hard, actually. You could use IO3 from the TC4 to control a random fire SSR for phase angle control. Artisan can control IO3 already, similar to OT1 and OT2. All that's missing is the little board that watches for the zero crossing on mains, and a bit of arduino timer manipulation to handle the phase delay. If interested, send me a PM.