In response to eric's comment on my PID autoprogramming ... I think actually the controller is going bad. Anyway, I reordered a Chinese controller similar to the one's you've written about, and a K thermocouple (total cost $35 ... worth it for experimentation) and I'm going to swap out the unit that David Blane installed initially.

BTW, I've looked around this and other forums (after a few 'odd' phone conversations with Blane) and see that Blane's reputation precedes him (little did I know ... this was my first prosumer machine). There were also hints by Chris' Coffee repair people (who are great) that Blane's choice of controllers may be unreliable. Coffee people are so polite, I sometimes have to read between the lines. Anyway, Blane gave me a good price so I can't complain too much, and it motivates me to figure out how the PID system works, and how to fix it.

Will post once I get the hardware and install

Chris

Eric; I read completely through your 'Cheap Chinese PID' controller writeup. Thanks. I'm confident now that I can do this all myself.

I pulled out the thermocouple that Blane uses, and found the following:

Watlow Style: 20 (plain sheath straight $14)
C: sheath diameter 1/8"
J: Calibration is Type J
F: Lead protection is fiberglass 24 gauge stranded)
G: grounded, round tip
M: 6" length
012: lead length is 12"
A: termination is standard 2.5" split leads

Cost for this configuration is $16 ... I could get this in a "T" type for the same price from Watlow-distributor.com. Maybe if my fix doesn't work

The Type J thermocouple is fine. Just remember to set your new controller for "Type J", visually check the polarity of the signal to the SSR and that of the thermocouple and you will be done.

westland wrote:BTW, I've looked around this and other forums (after a few 'odd' phone conversations with Blane) and see that Blane's reputation precedes him

Before slagging David, check who's doing the slagging and why. I bought my PID & parts from David after tons of FREE help in email and the phone. It's been flawless for 4 years. IMO, David is a standup guy who's outspoken manner ruffles some feathers.

His H-B posts...

edna713 wrote:I do not know WHY stock HX machines are popular. IMHO, an HX is optimized to make steam and VERY hot water w/ coffee as an afterthought.

It monitors boiler pressure! NOT temp. thus one COULD infer that it is basically a steam generator.

Ah, the flushing! the guess work and retraining, the sink shots, etc. etc. the constant refilling of the water tank -- if not plumbed in that is. The constant emptying of the drain tray -- if not plumbed in. The LOUD clicking of the 'high-end' Sirai pressure stat.

(If clicking every 20 seconds or so at idle bothers you or your S.O. -- beware!)


The energy waste, and on and on.

I owned a superb, brand new machine -- made in California -- and despised it.

Could not wait to unload it.

If one cannot afford a 'pid' HX, get a smaller machine and prep your milk, etc.
when you want it with a simple milk frother appliance = $75.00

dave

I hope my observation isn't perceived as 'slagging' (whatever this means, but it sure doesn't sound good). I received my new $30 controller yesterday, and installed it with the old TC (I've got a "T" type on order) and that seemed to be the problem.

Now when I had earlier called Blane with this observation, he claimed it couldn't be right, and wanted to charge me >$120 to install a new heater and labor (which he said was the problem, despite the fact that I had continuity checked the heater and found it weighing in at 11 ohms, so the heater must be working some of the time ... perhaps I'll replace it anyway).

To be fair, he had sent me a replacement SSR initially, stating that that was the problem. But all along, the SSR output on the original Delta controller has been in the 25vdc range ... much higher than the stated 10vdc it should have, and this along with erratic temperature readings led me to believe that the PID controller was bad. I think he was just getting upset that I was costing him too much.

He also told me that he couldn't be responsible for the machine unless it was returned in the original box (long since discarded, as we don't have space to keep these things around) and double boxed (in fact Blane didn't double box it when I purchased it). Essentially >$250 with freight to get it to him so he can swap out the heater rather than the controller. OK, I was a bit uncomfortable with all this. I can swap out the heater myself for $60.

The up side is that the cost of the machine with the PID controller was the same as getting a pressure stat machine from Chris' Coffee (CC). I know that Blane buys these from CC, and I suspect he gets them at cost, plus a credit for CC taking off the pressure stat and attachment plumbing ($37) which they can then use in repairs. Nothing wrong with that, as I'm still satisfied with the deal I got from David Blane. Plus he cut out the PID hole in the stainless steel -- not an easy task. I have no complaints about the bargain I made.

But I think the jist of the forum chatter is 'caveat emptor' ... you are responsible for the machine after you purchase it from Blane. I know this has forced me to learn how the machine is put together and what works and doesn't.

I think Blane could learn a bit from Chris' Coffee. They are basically upfront about wanting you to understand and fix your own machines. And they provide a complete set of replacement parts online for their machines. They are polite and helpful and informative. I would suggest that Blane get a set of protocols for handling phone diagnostics, and also getting a list of replacement parts and upgrades for his machines. This would save him a lot of headaches.

And I actually think Blane is right about the HX machines and PID controllers -- its a better system than the pressure stat. Potentially more reliable, easier on the heating element, and easier to tune (you can do it by pushing buttons on the front panel). In a closed system, there is an inverse relationship (at coffee temperatures) between pressure and steam temp established by the physics of water. One approach is not inherently better than the other as far as I can see. In the digital age, the PID/steam temp approach seems better.

erics wrote:The Type J thermocouple is fine. Just remember to set your new controller for "Type J", visually check the polarity of the signal to the SSR and that of the thermocouple and you will be done.

Eric:

I installed this yesterday, and did set this up as J. I've got a "T" on order, and will replace the J when it comes.

The unit I got was the JLD7100 from Lightobject (the non-ebay arm of Coldfusion X ... both are Marco Wong in Elk Grove CA). The manual indicates that the hardware is identical to the TEC-7100 you mention in your documentation.

In setting up the unit, I noticed that instead of an Atdu setting, there was a Hy setting; but in the new manual for the JLD7100, this is Caty PID algorithm but still seems to be Autotuning. The note says:

This controlled has 3 type of auto-tuning control methods already built-in.

0: Universal PID control suitable for increase/decrease fast speed of change of temperature application.
1: Gradual change PID control is suitable for applications that require steady change of temperature and speed of temperature change is not critical.
2: Fussy logic control suitable for system with oscillation and sensing signal delay.

I'm curious about the 'Fussy logic' feature

Anyway, I saw nothing related to Hy, so I've just left the setting at the default (usually safe).

Chris

"Fussy" logic is really Fuzzi logic and Mr. Wikipedia knows a little more than I - http://en.wikipedia.org/wiki/Fuzzy_logic

Atdu is simply the autotune offset, i.e. you are telling the controller how many degrees below Sv you want it to start autotuning WHEN YOU INITIATE IT. A reasonable choice for you would be 25 degrees. With older controllers, the operator (you) simply initiated autotune at 10% below normal Sv.

For the various types of control methods (0,1,& 2), I would try autotuning at each setting and write down the values of those parameters (P,I, d & others) that the controller can change when the autotuning is complete.

Hy is hysterisis but I do not have a good explanation for it (without doing a little research) as regards the application of it to this controller AND espresso machine boilers.

Just being facetious on the Fuzzy Logic ... my background is in stat, and I've had some lively conversations with FL theoreticians, who generally tend to be engineers. The engineers like it because of its roots in set theory. Within limits, it can yield useful algorithms, but I think neural networks are more reliable, and statistical models have the advantage of well defined information and fit measures. All can do the same things. (i.e., learn from the data, in this case the {on/off} signals and temperature histories)

Omega has a writeup on hysteresis:

"For heating control, the output is on when the temperature is below the setpoint, and off above setpoint. Since the temperature crosses the setpoint to change the output state, the process temperature will be cycling continually, going from below setpoint to above, and back below. In cases where this cycling occurs rapidly, and to prevent damage to contactors and valves, an on-off differential, or "hysteresis," is added to the controller operations. This differential requires that the temperature exceed setpoint by a certain amount before the output will turn off or on again. On-off differential prevents the output from "chattering" or making fast, continual switches if the cycling above and below the setpoint occurs very rapidly."

So I suspect the Hy controls the differential between the on and off setpoints (i.e., if you are at 121 C, then on would be something like 123 C and off setpoint would be something like 119 C.

They say this only applies to On/Off controllers, not PID. But I could see how you might want to set this. Of course the TEC-7100 manual doesn't say anything about it ... I wonder where the whole manual is?

OK, here is the updated set of commands for these Chinese PID controllers (I got this from the Auber site) http://ids313.info/JLD7100.pdf ... it has the Hy parameter listed, right before the Autotune parameter ... the JLD7100 is the same as far as I can see.