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Forum Index : Microcontroller and PC projects : WebMite in Silicon Chip Magazine
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Geoffg Guru  Joined: 06/06/2011 Location: AustraliaPosts: 3194 |
That is just me being lazy. I wanted NbrValves to equal the number of valves but that made the array Valve() have 9 elements so, when I initialised the array, I had to have an extra initialiser. I should have written the code thus: NbrValves = 8 . . Dim Integer Valve(NbrValves - 1) = (10, 9, 7, 6, 5, 4, 2, 1) Geoff Geoff Graham - http://geoffg.net |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 847 |
Thanks Geoff - you are not being too lazy! (I hadn't spotted the "NbrValves -1" - very clever!) Cheers, Andrew |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3150 |
Geoff--what is the layout of your 24VAC solenoids such that they have one common return to the PCB? Where and how do the returns join up? PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1873 |
I guess you don't have the article. It appears that all the valves are wired back to a terminal block on the board. There is one terminal for all the common wires. They are not shown on the schematic. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 847 |
Lizby and Palcal et al, Geoff has done an article on his website here It includes the circuit diagram, Gerbers, Construction notes and code. (It is hidden in the text of the first post on this thread) Cheers, Andrew |
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| palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1873 |
I looked on his site and didn't find it. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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| Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3194 |
Normally the valves are buried as a group somewhere in the garden. To save running individual pairs back to the controller the installers usually join one wire from each valve to make a single common wire and that is run back to the controller. This is normally done where the valves are located. You don't have to do this, you can terminate the commons in the controller's box. Geoff Geoff Graham - http://geoffg.net |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 847 |
Hi Geoff, I'm using your retic.bas v1.2 which doesn't have the 'NbrValves - 1' in the DIM . . . Valves statement (but has 9 elements to avoid errors). I notice that on your line 1200 you have "For i = 0 To NbrValves - 1" Is the " - 1" intended? (I'm not able to test it) (I have also noticed that fiddling with you code can have 'consequences' so I'm treading lightly.) Cheers, Andrew |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3150 |
Thanks, Geoff. Great project. I look forward to getting into the code. And indeed, thanks for all your efforts with MMBasic (and Peter's, and Tom's, and now Garry's)--what a fine development environment. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3194 |
Yes it is. All arrays start from zero and this is why NbrValves - 1 is needed. That is one of the great features of BASIC. It is in plain text so that you can 'fiddle' as much as you like. Geoff Geoff Graham - http://geoffg.net |
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| Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3194 |
It is all in the "construction pack" at the bottom of this page: https://geoffg.net/retic.html Geoff Geoff Graham - http://geoffg.net |
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| pd-- Senior Member  Joined: 11/12/2020 Location: AustraliaPosts: 122 |
I have ordered a couple of parts to do sum testing of a 24vDC powered unit driving 24vAC solenoid. i am going to use a AQZ102 SSR and a 0603L001/60YR Poly-Fuse on paper it should work. Information is a bit sparse on how long the poleyfuse will last for in a cyclic application so i think i will mount them on a daughter card as a consumable component. and do the design so i can revert to a fet and 555 if the polyfuse prove to be troublesome. |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
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| Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3194 |
The poleyfuse will only activate in case of a short circuit in the valve or its wiring and that should be a very rare event - and it will reset when the short is removed. The rest of the time it does nothing so I don't see how it could be regarded as a consumable. Also, they are readily available and cheap - a great solution. Geoff Edited 2023-09-09 12:47 by Geoffg Geoff Graham - http://geoffg.net |
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| pd-- Senior Member Joined: 11/12/2020 Location: AustraliaPosts: 122 |
It was to use it as a switch to provide a 24vDC pulse to the 24VAC solenoid and then trip and supply a low holding current to the solenoid. The parameters of the polyfuse Voltage - Max 60V Current - Hold 10 mA Current - Trip 50 mA Current - Max 40 A Time to Trip 1 s Resistance - Initial (Min) 15 Ohms Resistance - Post Trip (Max) 100 Ohms |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
Remember to keep polyfuses clear of other components. Some can run a bit warm. This looks like an interesting use for them. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Geoffg Guru Joined: 06/06/2011 Location: AustraliaPosts: 3194 |
That is unusual and I could see that the device might wear out. I would use a spare output from the WebMite driving a FET which would switch in a current limiting resistor in the common line. It would take a small change to the BASIC program but nothing serious. Geoff Geoff Graham - http://geoffg.net |
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| bigfix Senior Member Joined: 20/02/2014 Location: AustriaPosts: 128 |
Polyfuses have a wearout Polyfuse Lifetime This may be better Switching PTC Edited 2023-09-09 20:13 by bigfix |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
The cost of eight small 24VDC solenoids isn't exactly immense. Sometimes it's better to simply admit defeat, pay up and get the right tool for the job. :) (Cheap unless you want the posh, industrial brass body ones anyway! The Shakitobitsi Electronics (China) Company ones would probably have to be protected in something, but at eight quid...) Edited 2023-09-09 20:39 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| pd-- Senior Member Joined: 11/12/2020 Location: AustraliaPosts: 122 |
24VDC 25mm solenoids are listed at $59 each so $472 for the set of eight. And then im left with a box of AC solenoids. There only going to be used once a day at most for four months of the year ill do sum testing and se how they go |
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