Gene Café with PID Program Control

[speleomike]

Re: Gene Café with PID Program Control

Hi all

Problem solved. The control pot that came with the triac is a 0.5 MOhm and a very tiny turn of the pot (30 degs) reduced the power by 100%. What I was doing was reducing the power to zilch and the machine seemed to be turning into cool mode and I think thats what slowed the motor speed.

I have now put in a 100k pot and here is what I can control based on a watt meter in the power point.

Gene with no triac and heater fully on: 1360 W
Gene with triac set to full power: 1100 W fully clockwide
Gene with triac set to lowest power: 320 W fully anti-clockwise

So one can see the triac cuts the power to 80% (the specs with the triac say control from 0 to 90%) so one definately needs to have a switch to bypass the triac during rampup to FC (as the CoffeeTime article has). I have yet to wire that in yet.

Mike

[speleomike]

Re: Gene Café with PID Program Control

Hi all

Opps, sorry fan and heater are physically separate - above I indicated they were physically integrated together which is wrong. Somehow though when I use the triac I got the fan speed varies with the triac setting.

Ill look again tomorrow with some more tests.

Mike

[speleomike]

Re: Gene Café with PID Program Control

Hi all

Thanks Andy for the info about the Gene counting rotations - that would explain why my Gene beeped and turned off when turned down the power to the heater unit.

Yes I only wish to vary to heater power and I have a Watt Meter to monitor the wattage but it seems that the power wires that lead into the heater unit are for both heater AND fan motor. So when I reduce power via the triac the motor slows. The only other wires into the heater unit are the thermocouple sensor wires. Im not sure how the heater cuts off leaving the fan going at normal speed.

Ill have to pull the Gene apart again tomorrow again to understand this. Thanks Davec for the details above, its convinced me to not give up on this.
(Also the wattage drawn is the watts of the heater + fan and I presume that the fan is so much lower power than the heater that one assumes total watts drawn = power into beans.)

Mike

[andy]

Re: Gene Café with PID Program Control

As far as I can guess... the Gene counts / times the revolutions via the magnetic reed-switch on the left hand side.  If you slow the rotations it thinks the drum is stuck and turns it off (with a E3 error from memory).

That same reed-switch also tells the Gene "which way is up" so when it comes to the end of a cycle the handle is at the top.

I think Davec (nice post!) is on the money Mike.  You only want to vary the heater wire, not the fan or the drive motor.

[davec]

Re: Gene Café with PID Program Control

There are now 4 Genes (if not more) running the stage 1 and 3 modes on Coffeetime in 4 different countries, they all work fine. I think the poster Hazbean may well have hit on a good Leading edge dimmer for the project, but as always its worth checking with the dimmer manufacturer that you can run up to 1300W through it with extra heat-sinking (as I did). If the manufacturer is reticent, then the main thing to look at is the RF choke wires, if they are too thin, then it may well overheat, The triac in most 1000W dimmers is likely to be quite reasonably specced as they are derated due to the pathetically poor heat-sinking....beef that up and no problem. Funnily enough the more expensive trailing edge dimmers, especially those with soft start, sap too much power within the dimmer circuit and the cheaper leading edge dimmers seem to be better for this application.

Dimming the heating element on the Gene wired the way I have done does not slow down the Fan motor (which is not what I would want). I am wondering if the other posters problems are caused by a unit that is affecting the voltage in some way rather than simply clipping the sine wave?

Roasts using this mod are a huge improvement on the standard Gene, especially with the stage 2 mod. It allows you (in cold weather) to over-boost slightly and ramp up the temperature to a lower level then wait for first crack, rather than a slower ramp up to a forced first at a higher temperature than needed! The control of the roasting profile is excellent and now purely down to the skill of the user. A mains power meter (lkill-A-Watt?) is essential as the best control of the roast is obtained when closely monitoring the Wattage draw of the Gene and using that as a reference.

I do hope someone over there tries it (successfully)....really worth doing.

[hazbean]

Re: Gene Café with PID Program Control

I havent done the mod, but gave it some thought a while ago, enough to
come up with this

http://updates.clipsal.com/ClipsalOnline/ProductInformation.aspx?CatNo=31E1000L

as a candidate for a dimmer of fairly close spec to that suggested on coffeetime.

[speleomike]

Re: Gene Café with PID Program Control

Hi all

I have just tried one of these mods to my Gene by adding a "dimmer" so that the heater power can be controlled. Unfortunately it does not work as expected. It seems the Gene detects the current drawn or some impedance of the motor and when I have the "dimmer" in line the Gene turns off. Im interested if anyone else has made these mods and what worked as mine does not work.

Setup:
I have used a Jaycar CAT. NO. AA0346 Mains Motor and Lamp Controller. This is a triac and is different to the dimmer in the URL at CoffeeTime. This one has a 2-wire input for power and a 2-wire output for load and 2-wire control with potentiometer. I connected the heater output of the control board to the 240VAC input to the triac and the output of the triac to the Gene heater.
[tt]
+---------------+
Gene x-----| 240V output|-----x to Gene
Control | input output|-----x heater/motor
Board x-----| |
+---------------+
| |
/\///\///\//
control
pot
[/tt]
Operation:
The Gene would not turn on until the pot was rotated for no-dimming. The Gene then runs and the motor turns at normal speed and the heater operates. As soon as one turns the pot a bit to reduce heater power the motor slows (as the heater wires also controls the motor) and the Gene then immediately beeps and turns off. Clearly as soon as the triac starts to chop the power the Gene does not like it. The Gene control board would be "seeing" the triacs impedance instead of the heater/motor impedance and is not happy.

Has anyone here in Australia done a mod and what part number from what supplier did you use?

Mike

[davec]

Re: Gene Café with PID Program Control

Sorry to revive an old thread, but probably for similar reasons we have been modding a Gene Cafe, but with 2 objectives.

1. To improve roast quality and allow 300g batches of almost any coffee to be roasted as the element is dimmed, never switched off and on.

2. To allow roasting within a very wide voltage range (and potentially an over-boost capability for very cold weather).

Our mod dispenses with the need for a Variac and is cheap, easy and fully reversible, the main skills required are little more than those required to wire a mains plug. A test a few days ago allowed a modified roaster to roast perfectly with 3 roasts at a voltage of  226, 244V and just standard UK mains..which at the time was 237 (lower and higher voltages were created using a Variac).

More information here (although there will be updates to the documentation):

http://coffeetime.wikidot.com/gene-cafe-dimmer-control-modification

and an ongoing discussion on the forum

http://www.phpbber.com/phpbb/viewtopic.php?mforum=coffetimeboard&p=11701#11701

I hope its of use as its much easier than the PID mod, allows over-boosting the gene, roasting in a very wide range of voltage and is cheap. Sure its not computer controlled and uses the good old MK1 Human brane

[GoingPostal]

Re: Gene Café with PID Program Control

I am very interested in this mod, but cant seem to get the documents. Can anybody help me out here? Thanks

[TC]

Re: Gene Café with PID Program Control

Just to put the record straight, I have no intensions of selling or profiting on my mods.  ><snip>Enjoy!

MZ.

In the words of Foghorn Leghorn: "That was a joke, son" :P

[TC]

Re: Gene Café with PID Program Control

Hi  MZ, I sent a note to Genesis and they are very interested by your job as well as really impressed too.

I will PM you the direct contact, I will be very happy if you contact them, perhaps you might sell your brevet. you definitely deverse it.

All the best mate,

Serge

Suggest that you patent your work, MZ before Genesis rip off your intellectual property and then sell exclusively to a new supplier (non Cser) behind your back :P

[GoneBarista]

Re: Gene Café with PID Program Control

Hi MZ, I sent a note to Genesis and they are very interested by your job as well as really impressed too.

I will PM you the direct contact, I will be very happy if you contact them, perhaps you might sell your brevet. you definitely deverse it.

All the best mate,

Serge

[GoneBarista]

Re: Gene Café with PID Program Control

THANKS MZ  YOU HAVE ALL MY RESPECT [smiley=thumbsup.gif], THIS IS A GREAT JOB.

AND YOU  2MCM I WILL DO MY BEST TO MAKE YOUR DREAM COME THROUGH WITH THE 2 Kg ROASTER.

CHEERS,

SERGE

[TC]

Re: Gene Café with PID Program Control

Brilliant work MZ! [smiley=thumbsup.gif] Ill be calling you if I can ever scrounge together the bucks required for that 2kg roaster I fantasise about ;-)

Re: Gene Café with PID Program Control

Thanks for you encouragement, Im very happy with the whole system, it works a treat.


MZ.