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TC4 with aArtisanQ_PID
Have you set up the 'Extra Devices' tab? Heater fan and SV values are not recorded by default. You have the specify TC4 channels 3-4 to get heater and fan logged.

See my video here showing Artisan setup for TC4.
I tried to add extra device TC4_56 and adjust the Fan and Heater value manually.
1. During the roast, the right side heater LCD just show 0 , no matter how it changed on left side heater slider.
2. During the roast, at the bottom of profile it shows the fan and heater value, however, it disappeared when I stopped the roast. I attached the screen snap shot for your reference. Thanks a lot for your help.
Re-attach picture
sorry, I don't know why the attached picture does not show.
I attached a .rar file.
CJ098 attached the following file:
pictures.rar [313.66kB / 581 Downloads]
TC4 5-6 is Heater then Fan. In your screenshot you have them swapped.
Thanks a lot for your prompt response.
My original setting for TC4_56 is heart then fan. However, I found the fan value on left slider is inconsistent with the fan value on right side LCD. Besides, "6th" extra device on right side LCD seems no response. On the screen shot "test2", you can find the Fan value 98 on left side slider is the same with right side FAN LCD. but the left side heater value is 78, right side heater LCD value is 0.
Problem solved, Since I used OT1 ICC control heater and IO3 to control DCFAN
So I modified the Heater and FAN display options in user.h as below. Then it works.

// Heater and Fan Duty Dispay Options
// These should NOT need adjusting.  They control what gets streamed back to via serial
// These have no effect on operation and only affect what gets displayed/logged by Artisan
  #ifdef IO3_HTR_PAC // If using PWM on IO3 for a heater or DCFAN
    //#define HEATER_DUTY levelIO3 // Heater output is assumed levelIO3 with heater connected to IO3, command out when use DCFAN
  //#else // If using ICC control of a heater connected to OT1, Command out when use DCFAN
    #define HEATER_DUTY levelOT1 // Heater output is assumed levelOT1 with heater connected to OT1
  #define FAN_DUTY levelIO3 // Fan output is assumed levelOT2 for phase angle control mode on OT2, DCFAN on IO3
#else // PWM Mode
  #define HEATER_DUTY levelOT1 // Heater output is assumed levelOT1 with heatre connected to OT1
  #define FAN_DUTY levelIO3 // Fan output is assumed levelIO3 for PWM control of fan connected to IO3
CJ098 attached the following image:
Conversation continued here from the Gene/Artisan thread.


renatoa wrote:
Please include the flag for the two modes in User.h, and don't forget to comment with the biggest caps you find :) that P/I values from PoE(rror) are not working for PoM(eas).


MaKoMo wrote:

@greencardigan: shouldn't be there a TC4 PID command to switch the PID lib between those two modes from within Artisan? Could you add one? I plan to also add PoM mode to the Artisan Software PID and thus add such corresponding configuration to its GUI to toggle between the PoE and PoM modes. Thus if Artisan is configured to use the external TC PID, that user setting could just be send along a corresponding serial command.


renatoa wrote:

@MaKoMo & @greencardigan: if you have this opportunity to make a protocol change, please don't miss the great chance to add also a PID;LIMITS command, to pass the limits from Artisan Control dialog to the TC4 PID, and TC4 PID using them.

Was the most frustrating missing command for a long time... a permanent, 40% for example, minimum limit of power, would make my life a lot easier in my attempts to "perfect" rost profile.

I?m thinking we should modify the current PID tuning serial command? The PID library is expecting the P_ON_M or P_ON_E mode to be set at the same time as the PID parameters.

myPID.SetTunings(PRO, INT, DER, P_ON_M)

So I think it makes sense to include them in the same command and set them at the same time.

So we could change the PID;T;p;i;d command and accept either:

PID;PONM;p;i;d or PID;PONE;p;i;d

Any thoughts on this Marko, renatoa, others? Otherwise a new command would work too.

I also think a PID;LIMIT;min;max command will be a good idea.
Why not place the PonM/E flag as the last parameter, and make it optional, with default value PonE? this way others code built around TC4 will not be harmed... they can continue call the older version without recompiling.
Yes that's a good idea. However it would require a change to the cmdproc library. Currently it only accepts 5 parts in a command. The PID,T,p,i,d command already has 5 parts.
What is T? I don't see this parameter in the lib I have, PID_v1, from 2017/11/14...

void PID::SetTunings(double Kp, double Ki, double Kd)
The T is part of the TC4 serial command for tuning the PID, nothing to do with the PID library.

I'm working on a solution and will hopefully have a version to test this weekend.
What about adding simply a second tuning command that switches to P-on-M like


also to keep additional memory demand low?

Anyhow, I trust you will find a good solution. I prepared things on the Artisan side and can issue any command that you come up with easily.
This is essentially what I did. However I have kept the PID part of the command constant and use either T or T_POM.

Adding a new PIDM base command would be much less memory efficient.

Anyhow I sent you an email earlier before I saw your post here. Once we agree on the new command I will post a version 6.6 of the TC4 sketch here for testing. it seems to be working fine but I don't have time to test it more yet.
I've attached a new version for testing. I have done very limited testing at this stage.

- Added support for PID_V1.2 library with Proportional on Measurement mode
- Added flag in user.h to set default PID mode
- Modified the PID tuning serial command. Now accepts PID;T_POM;ppp;iii;ddd to set P_ON_M mode.
- The existing command PID;T;ppp;iii;ddd now switches to P_ON_E mode.
- Added new PID;LIMIT;min;max serial command to allow the PID output limits to be set.
- Cleaned code to remove compile warnings

The zip file also includes the updated PID_v1 library which needs to replace the existing library in your Arduino libraries fiolder.

Marko has already made the corresponding changes to Artisan v1.4 beta build. ThumbsUp
greencardigan attached the following file: [270.18kB / 560 Downloads]


greencardigan wrote:

I've attached a new version for testing. I have done very limited testing at this stage.

- Added support for PID_V1.2 library with Proportional on Measurement mode
- Added flag in user.h to set default PID mode
- Modified the PID tuning serial command. Now accepts PID;T_POM;ppp;iii;ddd to set P_ON_M mode.
- The existing command PID;T;ppp;iii;ddd now switches to P_ON_E mode.
- Added new PID;LIMIT;min;max serial command to allow the PID output limits to be set.
- Cleaned code to remove compile warnings

The zip file also includes the updated PID_v1 library which needs to replace the existing library in your Arduino libraries fiolder.

Marko has already made the corresponding changes to Artisan v1.4 beta build. ThumbsUp

@greencardigan: Did some tests today with this version and the current Artisan v1.3 beta on my Hottop-P/TC4 and it seems to work as expected. Thanks for your work!

@renatoa: Did you had a chance to play with this updated Artisan Software PID and/or this updated TC4 PID version yes?
No real TC4 here, so can't test greencardigan work.
But my actual controller, even if using a different control approach, looks and quacks like a TC4, so I can test commands coming from Artisan.
Will test also own Artisan PID next days... I can't drink as I roast Grin
Ok, I did some tests, and the new PonM mode works well, as expected, at least to regulate the air temperature in a hotgun style roasting machine.
The PI values I found satisfactory by trial and error were P=16 and I=0.8
The response time of a 150C step action was been 28 seconds, stabilisation with no overshot.

For those interested to experiment, they must be aware that in this mode the I term is the main driving factor of the heater, while P is a braking factor, almost as D term !
The difference between the P/D brake effects is the following:
- D term brake is related to temperature variation speed, stronger when fast temperature variance, i.e. in the steepest slopes of the profile;
- P term brake is related to distance to setpoint, lower when approaching.

An example, in my scenario, if playing with values above, someone should expect the following behaviour:
- for I lower than 0.8, or P higher than 16 => longer response time, maybe even undershoot
- I higher than 0.8 or P lower than 16 => shorter response time with slight overshot, maybe oscillations. For example 0.9 will stabilize in 26 seconds with a single 0.5C degree overshot, followed by no oscillation. Same behaviour if P = 14
At I > 1 or P < 12 someone should expect oscillations.

Stability can be achieved for other value pairs too, but with different response time.
For example P = 8 and I = 0.3 exhibits similar stability at setpoint, but reach the target temperature in 35-40 seconds.
Someone could prefer this way, with low values, if a slower start of the heating is desirable. Lower I/P values are for gradually increasing power, maximum power being reached maybe even in 10 seconds, while higher I/P values are for instant maximum power applied to the heater.

During this test was also been used the new LIMITS feature, maximum being set at 184 (of 255), equivalent to 72% of total power. As expected, it worked :)
Edited by renatoa on 09/09/2018 7:14 AM
Wiz Kalita
Is it possible to program a smooth curve for heater and fan power and force the TC4 to simply follow it? I find that on my popper ET follows output extremely closely and rapidly, so I believe I could get good results that way.
This is not good, to have ET and BT curves closely, i.e. like this:

... it's a sign that your BT probe measure more air than beans.

ET must be higher than BT by more than 50 C degrees during drying, and diminishing this delta to about 20-30 C degrees in the development.
Check this graph, it comes from a really well done fluid bed machine, and these are the right temperature evolution you should expect during a roast.

Unfortunately is very hard to achieve this on a popper, due to very turbulent air circulation, in a too small roast chamber, making an accurate BT reading almost a lottery.
For a popper I would drive my roast exclusively on ET, as I wrote in the other message earlier today, see "well tempered roaster" thread.
Edited by renatoa on 09/09/2018 7:07 AM
Wiz Kalita
This is true, and my curves look like your first one. I'll switch to controlling on ET from now on. But what I meant was that OT1 and ET follow each other close enough that I think controlling on OT1 directly without any PID could be a good idea.
Hi all,

The was an error in version 6_6 that stopped the sketch from compiling in one of the modes. This release fixes that issue.

Github download link - aArtisanQ_PID version 6_7

I've also updated some guide documents relating to the aArtisanQ_PID sketch which may help new users get going. However, the guides assume you already know how to program an Arduino.
greencardigan attached the following file: [473.3kB / 643 Downloads]
Two questions for anyone that has a deep understanding of TC source:

- why there is no data stream output, for any protocol, if standalone mode is chosen ?
Somewhat related, why no buttons/profile available if using an external roasting app?
In both cases the reasoning is same as above, maybe I want to roast with internal TC4 profile/PID and send data to Artisan... seems not possible with actual code.

- the second is about power control when using ICC... at some moment in time inside the ISR routine, at line 151, the Bresenham's algorithm decide to raise OT_ICC pin to HIGH. I don't see where in the code/moment in time, where the OT_ICC pin is reset to zero before the start of the next half sine, which is mandatory, imo, else the ZCD will never trigger one more time the ISR. And the heater will remain full power on forever. At least so happens to me...

btw, in my twisted mind, ISS should logically reside in same module as slow PWM control. Using a ZCD doesn't not make this method belonging to the phase angle principle, is still an on-off method, very fast and synced with frequency, but on-off.
Why would be this preferable... because there could be cases of ZCD malfunction, experienced them, where merging ICC with PWM in the same code would allow instant switching from ICC to slow PWM if ZCD fails/timeout. And save the roast... Grin
I don't have a full understanding of how the ICC code works but I will have a look at when I get a chance.

I believe that I didn't see any need at the time to include any output stream in standalone mode. It was intended for use when logging software was not being used. Maybe the TC4 profiling and buttons could be activated when in other modes? Actually it appears that the profile code is active in all modes. As you know there were low memory issues at one time and the button checking code was disabled in other modes to try and reduce memory usage. It is quite possible that it could be added back in as there was also some other memory savings.

Regarding the ICC and PWM being separate , this was a result of my merging of Jim's two branches. He had a PWM and phase angle control branches each with their own libraries and I simply merged them and include the appropriate library as required.
I had some free time this weekend and did a little experimenting with PID control, since this has been discussed again a few times recently. I noticed that PID behaves very differently in the sketch I have been using (based on an old aArtisan v3.10) compared to the latest aArtisanQ_PID.

In particular, my PID tuning parameters worked decently well on the old aArtisan sketch. But on aArtisanQ_PID, they gave serious oscillations, and heater output jumped only between 0 and 100%. Interestingly, this depended a lot on the tuning parameters used:

* Without a D-term, there was no appreciable difference.
* With a large D-term, aArtisan was fine, but aArtisanQ_PID oscillates.

After a lot of digging I think I found the issue: In aArtisanQ_PID the PID calculations are only done once per iteration of the main loop. Given the ADC delays, that's about once every 1.25 seconds. In the old aArtisan, the PID was also updated during the delay loop waiting for the ADC. I think this is especially bad for the D-term, since the error can change quite a lot in 1.25 seconds.

In any case, updating the PID during the delay loop seems to fix the issue for me, and PID control is now stable even with a large (32) D-term.

greencardigan, I have sent you a draft pull request on github - perhaps you can have a look. If anyone wants to give it a test in the mean time, the code is available here:
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