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Forum Index : Electronics : Piclog - Star/delta logic suggestion
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| domwild Guru  Joined: 16/12/2005 Location: AustraliaPosts: 873 |
Friends, My suggestion for a star/delta switching logic using pseudocode. Why pseudocode? Not everyone is a C/Java/Picaxe person and hopefully my indentation shows the begin/ends and even more important, my logic is correct! The problem with the Picaxe is that we may run out of variables, so I am suggesting to use a bit for the first variable called STAR. [code] Logic: Initialisation section: star = on ;;use a bit here subroutine stardelta if rpm > ? ; change to delta on "high" rpm then star = off switch star to delta return if rpm < ? ? ; "lower" rpm, back to star then star = on present is delta, change switch delta to star return end sub [/code] Problems: 1. Working out ? and ??; sufficient gap, has to have hysteresis, so we do not have hunting from star/delta/star. 2. We do not want to call this sub when there is no wind/rpm, we want to be in a sleep mode then. Any suggestions? Or logic errors? Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
A TAB turns into &nbs p; confusers never cease to amaze me. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I edited the post for you to help with the formating. The forum has a CODE /CODE option that "sort" of works. If you ever run out of variables in a PicAxe, you can store data in the eeprom space. It means swapping data between the eeprom space and variables, and its slow. My charge controller uses the eeprom space to store the display text. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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GWatPE Senior Member  Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
I cannot see how you would run out of variables in this application of a picaxe. I also cannot see why you would now switch windings to give a lower cutin when there are proven switchless ways to do it. Just a thought! Gordon. become more energy aware |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
Gordon, Thanks for that. In Piclog we use the following variables: RPM, VOLT, AMP, perhaps wind velocity, perhaps watts and perhaps maxima of Amps. Some of those cannot be byte-sized variables. Haven't we just run out of room with this list? Have not done any programming lately! I always thought the idea behind star/delta switching was to get more Amps out of the system at higher wind speeds and therefore RPM. Is star/delta switching dead? Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
I would say in systems below 1kW that capacitors, as voltage multiplying functions, offer a better solution to optimizing windmill loading. It is very early days with this. Not many readers seem to have tried this yet. The winding effectively stays in the lowest resistance configuration that will provide output at the higher power levels. This is covered in other threads. The picaxe has 7, 2byte variables. These can be any combination of words or bytes. There is provision for bits as well, but I have not needed flags as yet. I would not attempt to use the piclog to perform the star/delta switching, in addition to logging. Better to use a dedicated micro. Gordon. become more energy aware |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
Glenn: Thanks for improving the looks of the code. Have not tried this option before. Gordon: Thanks. I was not even thinking of logging, just the simple rpm, amp, volt and perhaps wind speed as suggested by Glenn with his simplest 08-driven setup. I do not know if Glenn called this scheme also "Piclog". Without logging my scheme (star/delta) might be possible. But caps are certainly a more elegant solution and do not require six wires down the pipe. Logging would still be possible via the RS232 interface followed by a temp. laptop to take the ASCII stream of rpm <comma> amp <comma>, etc. or similar. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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