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replacing Giotto controller with a DIY controller

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  • #16
    I been browsing the wemos mini, will you run the screen and SD card as well?

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    • #17
      I’ve ordered the screen to play with, but it probably won’t go on the final version as I’m mounting the whole lot inside the machine...

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      • #18
        Originally posted by iaindb View Post
        So are you saying the DC pressurestat is a problem?
        Given identical load and voltage, DC Contacts need to be a bit beefier and have a means of quenching (usually magnetic) the arc resulting when the contacts are opened while loaded. This scenario doesn't apply when being used for an AC load.

        That's why it is always important to properly specify relays/contactors for the type of load to which they will be subjected.

        Mal.

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        • #19
          Originally posted by Dimal View Post
          Given identical load and voltage, DC Contacts need to be a bit beefier
          Yes, when comparing identical load and voltage, but I'm referring to the GPP wiring which is either a) low voltage (5V/12V?) DC negligible load on the pressurestat; or b) 240V AC carrying 1500W!

          Buuuuut I'm trying to get some clarity on the Giotto wiring "versions", as I've seen wiring diagrams saying the in-line pressurestat is the latest, but the one posted above says the pressurestat wired separately to the control box is the latest...

          thanks!

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          • #20
            Originally posted by iaindb View Post
            Yes, when comparing identical load and voltage, but I'm referring to the GPP wiring which is either a) low voltage (5V/12V?) DC negligible load on the pressurestat; or b) 240V AC carrying 1500W!
            The P/stat contacts will be fine and designed to handle the miniscule load placed on them (a relay coil).
            The relay main contacts are well able to handle the load required of them.

            Mal.

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            • #21
              Originally posted by Dimal View Post
              The P/stat contacts will be fine and designed to handle the miniscule load placed on them (a relay coil).
              The relay main contacts are well able to handle the load required of them.
              We're talking passed each other... Perhaps I'm not explaining myself properly. But nevermind, my parts have arrived so I'll wire it as it is currently.

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              • #22
                Le parts have arrived. They're quite tiny!

                Click image for larger version

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                • #23
                  Originally posted by iaindb View Post
                  Le parts have arrived. They're quite tiny!

                  [ATTACH=CONFIG]23055[/ATTACH]
                  Les parts

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                  • #24
                    wow the last quarter of last year was tough... I still haven't finished this project. I have built the software and assembled the controller, but that's it.

                    I'm thinking of a Panasonic AQA411VL 25A SSR, as that's what coffee parts sells for similar machines. Yet to get that.

                    In the meantime I wired the relay via the pressurestat switch. It's rated for 240V but I know they burn out after some time (hopefully a couple of years of light use).
                    Attached Files

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