PID Corretto

[wrstikoff]

Re: PID Corretto

I reprogrammed the roaster to roast for longer. Roast profile attached below.

Now just need to wait to try it I guess

[Mocha_Zarba]

Re: PID Corretto

Fantastic stuff mate, cant wait for the result.  


MZ.

[Corretto]

Re: PID Corretto


Yes, it does look great indeed.

So can anybody perform this mod?

[Dimal]

Re: PID Corretto

It would be a fairly straight forward Mod to do but to get the best out of your Corretto, youd need a slightly higher spec controller..... one that has the capacity to introduce several ramp/soak stages through the roast cycle and then to take it a step further, a controller with comms capability as well to allow you to store and run Roast Profiles.

Other than that, the installation side of things is not that dissimilar to installing a PID controller to a Silvia, etc. I suppose if someone had the time and resources to do it (a la Jims Silvia PID Kits), a standard kit could be assembled, programmed and packaged for use on pretty well any kind of roaster with slight differences depending on the heat source intended.

Mal.

[wrstikoff]

Re: PID Corretto

It would be a fairly straight forward Mod to do but to get the best out of your Corretto, youd need a slightly higher spec controller..... one that has the capacity to introduce several ramp/soak stages through the roast cycle and then to take it a step further, a controller with comms capability as well to allow you to store and run Roast Profiles.

Mal.

Hi Mal,

The controller indeed has comms capability - RS232. The graph is produced from the data capture during the roast. Also used for changing the roast profile

Being new to roasting I dont know about ramp and soak. I can program profiles in 20 second intervals within the limits of the heat gun power output (the yellow line, also captured) and about 26 minutes duration. Any input into improvements in the profile would be hugely appreciated.

For you interest I guess, the controller is an Atmel ATmega8. Which is an 8 bit programmable micro processor.

It can store only one roast profile at the moment (actually 2 - one is hard? (maybe firm :-?) programmed the other is changed using the RS232 (loaded from excel) so I can keep as many profile as I like.

Cheers
Dave

[JavaB]

Re: PID Corretto

OK, dredging up an ageing thread :

Ive been roasting for a while now with a PIDed Corretto..... and the results are fantastic!!

The PID is a 30 stage Ramp/Soak unit available on that Evil site for around $100 Australian.... The temperature probe Im using is the one supplied with the Jaycar data logging multimeter.

I have programmed the PID to ramp up the temperature to 150C, hold it there for 3 minutes (to "dry out" the beans) then ramp up the temperature steadily to about 200 degrees fairly rapidly, then to 210C more slowly and then to 230C - VERY slowly....

The output of the PID goes to a solid state relay which switches the heater element of the Ryobi heat gun.....

The temperature set points can be easily changed for different bean varieties..... and you can store about 3 profiles in the PID and select which one you use.....

The autotune function works perfectly with an empty Corretto.... but there is over/undershoot in temperature with beans in the bowl and the PID is autotuned - easily fixed by fine tuning the P I and D values manually....

The results, as mentioned above.... are perfect.. There is a steady uniform start to first crack and then a smooth increase in temperature as the beans approach and then enter second crack. The time for the two stages is 100% repeatable (for a given bean variety) making it easy to pull the roast 10 seconds before, just at, or 10 seconds after the start of second crack.

So for anyone wanting to take their roasting to the next level, a fairly inexpensive and simple solution.

[Corretto]

Re: PID Corretto


Sounds Fantastic Java.

I want one and I want it now :-)

Trouble is to find someone to put it altogether for a technically challenged Coffesnob.

Any pictures???


Belinda

[JavaB]

Re: PID Corretto

Hi Belinda....

Yep, Ill get some photos organised shortly.

Its not too hard to modify the heatgun etc.... but does require someone with some electrical knowledge unfortunately...... check out a your friends, neighbours etc..... Its amazing what you can "buy" for a kilo of freshly roasted premium beans.....

I was super impressed with the results I was getting before this mod..... but after modifying with the PID it is totally "hands free".... just flip the switch and wait for the beans to be roasted - to exactly whatever level you desire.

I cant imagine any roaster doing a better (or easier) roast.....

As Big Kev used to say "Im excited"

[Corretto]

Re: PID Corretto


Yes, it does sound exciting. Exactly what I wanted for the setup soon after it came into the world as a new roasting method. Which incidentally is just over one year ago now

This could be a nice Birthday pressie for it [smiley=evil.gif]

I should be able to find someone to do it to, though not sure if the electronic Bosch HG should be used though, probably something lesser.

What exactly does one look for on Evil Bay, eg what is it called?


Belinda [smiley=engel017.gif]

[Paolo]

Re: PID Corretto

JavaB
This sounds FABULOUS!!

I cant wait to see the photos.

I want one too!

[JavaB]

Re: PID Corretto

What exactly does one look for on Evil Bay, eg what is it called?


Belinda [smiley=engel017.gif]

Belinda,

Just search for "ramp soak"..... and you will find the item (international seller).

The Bosch could probably be modified.... but it would be easier with a simple gun - like the Ryobi 2 speed.

[Corretto]

Re: PID Corretto


Java, does the PID control the fan speed to the HG as well or just the heat?

Where are those pictures? Enough time already :


Belinda

[JavaB]

Re: PID Corretto

Hi Belinda....

Been at a nieces First Communion.... after which was a family function...

Here are some photos.....

The PID (removed from the plastic box it normally lives in to prevent little -- and no so little :) fingers touching the 240V.... ouchie... ouchie





The red wires on the right go to the Jaycar thermocouple.... There is a relay O/P version and this one - highly recommended... drives a Solid State Relay.

The SSR mounts on the back of the board which holds the heatgun (see posting in heatgun sections for frontal view). It needs to be mounted on a heatsink.... but not as big as the one I used which was a piece of Aluminium U channel I had lying around...



The leads between the SSR and the PID are only 12V signal leads.

The fan (and low temperature element which powers the fan) are not affected by the PID.... so there is a constant air flow into the bowl.... only the main heater element is controlled- and that cycles every couple of seconds to maintain the set temperature.

I personally wouldnt change the fan speed.... as the fan is keeping the HG relatively cool... At the end of the cycle the main heater is turned off and the fan continues to run - thus cooling the HG.... The air from the HG could be used to cool the beans.... but not as effectively as dumping into a colander with a more powerful fan.

[robusto]

Re: PID Corretto

Nice work JavaB. Sure is a nice level to aspire to.

When you mentioned ramp and soak PID and bay of evil, --- I instantly tought "Auber PID".

Yep, pictures confirmed it. Now if you had a Silvia instead of your Cimbali, you could have gone for a twin set.

-Robusto

[JavaB]

Re: PID Corretto

Thanks Robusto,

Its a relatively simple mod and not very expensive....

The PID was about $120 including shipping, the SSR was $8 and the box which houses the PID cost about $8 as well....

It means you can use an inexpensive heat gun (the Ryobi is about $40 and very well built) - and have very fine and repeatable control.

Past first crack its great watching the temperature increase by 0.1 of a degree every couple of seconds... nice and smoothly with no risk of stalling the roast....

I just sit back and let the automation kick in and do the work.....

Now to work out a way of automatically dumping the beans into the cooler at the end of the process :..... there is an alarm output which operates at the end of cycle..... at least it can sound and wake me up if Ive fallen asleep so I can initiate the cool down ;D ;D