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PID Mod for Silvias, Gaggias, etc

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  • #16
    Re: PID Mod for Silvias, Gaggias, etc

    Hi again Craig,

    Taking your questions in turn:

    A1) This is ideal of course, as the fewer the number of temperature transition points there are, the better. That being said though, with such a small boiler it doesnt really matter all that much and brass/stainless steel, etc are very good conductors of heat so it would be acceptable to attach the t/c to the surface of the boiler. The simple answer being NO.

    A2) Im not familiar with the physical characteristics of the boiler in your particular machine, but if it was possible to attach the t/c close to the position of the original Brew T/stat, thats what I would do. Apart from that, if you attached it relatively close to the discharge into the Brew Head then that would also be ok.

    A3) Redundant

    A4) Redundant

    Hope that helps you out Craig. The parameter of concern with these sorts of decisions is the "time" it takes between a change in temp taking place and how long before that change is detected and acted upon. In large boilers this can be critical but in boilers with capacities less than half a litre and a relatively large Heating Element, it is of no real consequence. With this application, you can think of it as Thermal Intertia.

    This time delay, if significant enough, can lead to instabilities in the temperature control which can result in large oscillations of the water temperature. In these type of situations, PID controllers really come into their own and especially those with Fuzzy Logic assistance.

    The FL uses algorithms which interface with "rules" that attempt to replicate the way humans think and work, and can "learn" to cope with a wide range of differing operational circumstances and disturbances in the process. FL and Artificial Intelligence originated from similar beginnings and are kindred philosophies as a point of interest.

    After all this, I hope I havent muddied the waters. There is a plethora of information about this kind of thing to be found on the Net and if you wanted to know more about it, this isnt a bad place to start
    http://www.expertune.com/tutor.html

    All the best,
    Mal.

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    • #17
      Re: PID Mod for Silvias, Gaggias, etc

      Hi again All,

      Just discovered an alternative method for attaching the SSR in PID modded machines that avoids the need to drill holes in the panelling anywhere.

      How do you do it? Well, with double-sided adhesive Thermal Tape of course. I bought some from these people... http://www.coolpc.com.au/catalog/ a while ago for upgrading the cooling of chipsets on PC motherboards and video cards where pinning or fixing by more usual methods was either impossible or less than ideal.

      After giving these installations a caning over the past few months Im more than happy with the performance results and "permanency" of the attachment. This stuff is a breeze to use and will stick like the proverbial to pretty well anything, and can be found here... http://tinyurl.com/5yfo6. Will be trialling over the next few months so will report back in a couple of months time.

      Cheerio,
      Mal.

      Comment


      • #18
        Re: PID Mod for Silvias, Gaggias, etc

        Good to hear your PID mods up and running MAL.

        I used double sided tape as well.
        Certainly saves drilling the case, also allows the mod to be removed without a trace etc.

        Got any pic?

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        • #19
          Re: PID Mod for Silvias, Gaggias, etc

          Hi again Craig,

          Afraid I still use old fashioned technology where cameras are concerned and still have a few piccies left on the roll. Once Ive managed to use these up and have the film processed, will scan and pin-up for info and comments/feedback.

          My old work-horse camera is a 31 year old Nikon F2s with assorted lenses, filters, etc and still looks like new despite having travelled with me where ever Ive gone. Had it serviced recently and the shutter timing was still within Nikons published tolerances. Not too shabby for one of Nikons first System cameras and is probably why I still have it and resisted the urge to go digital.

          Anyway, will post everything up as soon as I have something worth posting, so until then, have to use your imagination.

          Cheerio,
          Mal.

          Comment


          • #20
            Re: PID Mod for Silvias, Gaggias, etc

            Ebay USA has several on offer, with at least one willing to export to Australia for $25. www.ebay.com and type in pid temperatue controlers. This one, for example, Fast Fuzzy PID Temperature controller BTC-2500-511111, works out at about $AU115 including postage. You would then have to buy the relay, thermocouple and power supply, and research whether it is suitable for your needs.

            Comment


            • #21
              Re: PID Mod for Silvias, Gaggias, etc

              Hi robusto,

              Thanks for that info. I think when its all said and done though, youre probably better off trying to source a suitable device locally. You are more likely to receive technical and practical assistance from your local supplier if installing and setting up a PID controller is not something with which you are familiar.

              Also, should the unit prove to be faulty, it is a much simpler proposition to contact your local supplier for assistance and warranty support.

              On the subject of specifying Fuzzy Logic PID devices, this really is huge over-kill for such a basic application as controlling the temp in a sub 1,000ml water boiler. Theres lots of information about this on the web and Ive alluded to a small cross-section of this in a couple of posts above. A straight PID Controller is more than adequate for the task and is in itself, way more than what is needed to achieve control of +/- 1 degree C.

              Cheers,
              Mal.

              Comment


              • #22
                Re: PID Mod for Silvias, Gaggias, etc

                Originally posted by Mal link=1102703274/15#16 date=1109685891
                Just discovered an alternative method for attaching the SSR in PID modded machines that avoids the need to drill holes in the panelling anywhere.

                How do you do it? Well, with double-sided adhesive Thermal Tape of course.
                I did the same thing with mine, Mal. Probably a different brand than you used, but basically a 5cm x 5cm (2 inch x 2 inch) square piece of double-stick foam tape. That was about a year ago. The installation has been perfectly stable.

                You can see my PIDed Silvia at
                http://www.terrystockdale.com/coffee/journey_5.shtml
                and
                http://www.terrystockdale.com/coffee/espresso.shtml

                Terry

                Comment


                • #23
                  Re: PID Mod for Silvias, Gaggias, etc

                  Originally posted by dragon link=1102703274/15#21 date=1110504400

                  I did the same thing with mine, Mal. Probably a different brand than you used, but basically a 5cm x 5cm (2 inch x 2 inch) square piece of double-stick foam tape. That was about a year ago. The installation has been perfectly stable.

                  You can see my PIDed Silvia at
                  http://www.terrystockdale.com/coffee/journey_5.shtml
                  and
                  http://www.terrystockdale.com/coffee/espresso.shtml

                  Terry
                  Hi Terry,

                  Great to hear from you by the way.

                  Was the tape you used a Thermal Conductive Tape or a straight Double-sided Adhesive Tape? From your "Journey" treatise, Im not sure if you used the tape to attach the PID box to Silvia or for the SSR.

                  Either way, It probably doesnt really matter a great deal when you oversize the SSR by a factor of two to three times, as a lot of people seem to do. Its probably more important that the SSR isnt sited within the Boiler environment, thereby thermally stressing the device unnecessarily. Always better to try and keep electronic devices cool.

                  I used the tape because my Mokita doesnt have a lot of spare room internally to mount the SSR using screws and nuts (Silvia is a bit bigger and seems to have plenty of spare room), and if I did fix the device this way, I would have ended up with the screw-heads visible on the outside of the s/s panelling... not a good thing.

                  Just to be safe, I tested the Thermal Tape on a couple of PC chipset coolers and a video card processor cooler. After quite a few months, none of the coolers even looked like theyre going to shift and the tape seems to do a good job of transferring the heat to the HSF units in each case. Good enough for my little Mokita upgrade I thought.

                  Anyway, to cut a long story short... the tape seems to be working quite successfully with the PID/SSR mod to the Mokita and may offer an alternative method of fixing devices to the internals of espresso machines where their owners had previously decided against such mods because of the need to drill mounting holes through the machines s/s panel-work. So far, so good and as soon as the film roll is ready to process, will post piccies up of the progress through the entire mod process. Until then,

                  Cheers,
                  Mal.

                  Comment

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