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).
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replacing Giotto controller with a DIY controller
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Les partsOriginally posted by iaindb View PostLe parts have arrived. They're quite tiny!
[ATTACH=CONFIG]23055[/ATTACH]
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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.Originally posted by Dimal View PostThe 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.
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The P/stat contacts will be fine and designed to handle the miniscule load placed on them (a relay coil).Originally posted by iaindb View PostYes, 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 relay main contacts are well able to handle the load required of them.
Mal.
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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!Originally posted by Dimal View PostGiven identical load and voltage, DC Contacts need to be a bit beefier
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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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.Originally posted by iaindb View PostSo are you saying the DC pressurestat is a problem?
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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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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I been browsing the wemos mini, will you run the screen and SD card as well?
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Thanks Mal, I happily defer to your expertise as I’ve seen inside a grand total of 1 of these machines!
So are you saying the DC pressurestat is a problem?
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Or, maybe this one...Originally posted by iaindb View PostYou can see the two different wiring options in this PDF: https://www.home-barista.com/downloa...E-13.03.09.pdf
https://coffeesnobs.com.au/attachmen...a-part2of2.pdf
Mal.
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You could probably rewire it, as I think this ac pressurestat was redesigned to use the same pressurestat as a dc input. From what I can gather the AC eventually burns out the pressurestat switch.Originally posted by Jackster View PostI have a similar issue, but my pressurestat runs ac to it. My SSR are DC triggered, so waiting for some ac-ac SSR to arrive.
But watching this to see where you end up...
You can see the two different wiring options in this PDF: https://www.home-barista.com/downloa...E-13.03.09.pdf
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I have a similar issue, but my pressurestat runs ac to it. My SSR are DC triggered, so waiting for some ac-ac SSR to arrive.
But watching this to see where you end up...
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For those following, I've ordered a Wemos D1 mini, as it has plenty of DIO, one analog input I can use later for the PID, and includes WiFi on-chip. It has relay shields, but I'll need a separate SSR for the element - probably a Fotek 25A or something like that - it will need to trigger off 3.3V. Just waiting on APost to deliver the parts!
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