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Forum Index : Electronics : Mega-piclog
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Just a little show and tell. I've been building a new logger / controller based on the Piclog. Its using the new 20X2 Picaxe chip, and will be used at a remote 24v site with one of Phills windmills. 
It will log wind speed, wind direction in 30 deg increments, battery volts, windmill current, load current and dump load current. It will also be measuring 3 additional 24v feeds from other equipment. The unit will act as a dump controller, based on the setting of two trimpots ( one for high volts and one for low volts, similar to the TL084 controller ). A mosfet output is used to drive a 60amp relay to switch the dump load. I'm using 3 old current transducers instead of Alegro sensors. The transducers have a gain and offset adjustment, making them easy to set up and give a higher current resolution for logging, though they do require a +-15v supply. The Piclog PC software was re-written from scratch for this project. As well as processing the extra input data, the new version sends its log data over the internet to a remote server. The PicLog circuit sends data every 2 or so seconds, the PicLog PC software averages this data over a minute, and then sends the data using a http request to a web server. By using http traffic on the default port 80, we dont need to worry about firewalls. The PicLog PC software also stores a copy of the sent data, incase there is a down server or internet connection. The web server stores the data in a Access database. The data can be searched and reported, with pretty graphs, using good old ASP web pages. Its all working, fired up last weekend. I'm currently building a box and making it all look nice. The 20X2 is noticeable faster than the 08M chip! Once its finished, I'll publish the complete circuit and software incase anyone else wants to build one. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Downwind Guru  Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Looking good Glenn, Nice work. What were the transducers out of? What clock speed are you running the 20x2 at? Pete. Sometimes it just works |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Pete The transducers were from an old welding robot. They have a 13mm hole so will read some serious current. I'm running the 20X2 at its default 8MHz, seams quick enough and the serial data is sitting at a nice speed of 9600baud. To measure wind direction I'm using a 12 position rotary switch with its end stops and the little indent ball and spring removed, so it can rotate the full 360 deg will no "cogging". I've soldered on a series of resistors as a voltage divider, and feed the output into a analogue input of the piclog. The PC software has a calibration screen where you set up the window of value for each 30 degree position. Eg, at 30 deg the analogue reading might be 100, so I set the window from 90 to 110. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Today I built its box. To save a few bucks I thought I would make the box from scratch. I used the guillotine at my work place to cut up some scrap aluminum for the sides, top and bottom, and used some L section to pop rivet it together. It took about 2 hours to make  , next time I think I'll just spend the money and buy a box from Jaycar.
Its 300mm wide, 210mm long and 70mm high. 
Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Nice work. 
Yea short cuts always cost more in the long run, but think of the fun you had doing it. 
You were lucky to find a piece of ally with the text on it in the right location for the front panel 
Do this mean we will get a step by step instruction on box enclosure construction as well. Pete. Sometimes it just works |
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vasi Guru Joined: 23/03/2007 Location: RomaniaPosts: 1697 |
Hi Glenn, Picaxe 20x2 is based on PIC 16F690? Nice looking project. Your CNC Router is at the old location? Vasi Hobbit name: Togo Toadfoot of Frogmorton Elvish name: Mablung Miriel Beyound Arduino Lang |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Vasi Yeah the router is still at the old place, its got too much junk piled on it to use at the moment. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| vasi Guru Joined: 23/03/2007 Location: RomaniaPosts: 1697 |
Found it! Is about 18F14K22. I looked in datasheet, the maximum recommended impedance for analog sources is 10 kΩ. Better than my 18F2550 where maximum is 2.5 kΩ  .
It also have independent selection of analog inputs. The raw pic 18F14K22 can be easily programmed with Swordfish Basic SE edition (free) with no limitation regarding to program length but only 256 bytes of RAM memory (for variables) can be used from a total of 512. You need a programmer. CPU speed is a maximum of 16 MIPS, better than 5 MIPS as found in Picaxe 08M. Hobbit name: Togo Toadfoot of Frogmorton Elvish name: Mablung Miriel Beyound Arduino Lang |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi Vasi, I could not work out what the heck you were on about till i realized the 18F14K22 pic is the blank chip the picaxe 20X2 is created from. The nice thing about them is a faster internal clock speed to go with the beefer capabilities. Pete. Sometimes it just works |
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
Be careful with the "60A" relay, solder the connections and TEST IT, make sure it will handle 40A at least. I destroyed a 30A relay in a few minutes as it got hot on the terminals with less than 20A, obviously the terminals are the same(as the 60A relay) so 20A with a spade terminal is pushing the firendship. I ended up with the SSR, for no other reason than it was the same price as Jaycar 60A contact one you have shown and it has bolted connections, uses less juice too. at $20 doesnt break the bank and given your install is from scratch you can utilise a separate set of recs to feed an SSR and the dumpload. Also keep in mind if this thing is as good as mine -(which it will be or better) driving 24V all the amps are doubled, thus 35A are well within reach for an 80S Star / 100S delta combo. 35A doesnt sound like much, but it means you'll need to solder all the connections to the RECS, mount them on heatsinks. Should be a winner and everything looks better (AMPS wise) at 24V. Are the transducers capable of measuring the output to within 1/10ths of an amp? If not they may be a little all over the place. 75mV 50A shunts are about $5 on ebay BTW. Thats my 2c worth! Luck favours the well prepared |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Glenn, Wondering why you used a v-reg module rather than a 7805 etc. Or wat it just because you had one kicking around. Pete. Sometimes it just works |
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| KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
I'm also sure you wont need any help with the cap voltage doublers and as for the perfect match of CAP size I dont know. What I do know is i'm running Phills suggestion for 680uF 450V caps back to back giving 340uF. These are readily available on ebay for ~$2 USD each but postage is a little dear at $30++USD tube amp cap drop him a question and he will list the 24 that you need. Luck favours the well prepared |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Karl, yes the current transducers can be adjusted to read over a wide current range, from milliamps to hundreds of amps. The use of the transducers means I can have twice the resolution of a Alegro chip, and easily adjustable on site. The little flutuations in current affecting the watt hour readings is a problem with the way the existing Piclog code records its data. When it records a log entry, it saves the current values at that moment, so any little flutuation is recorded. As watt hours are a tally of the readings over time, its easy to see how the little flutuations can add up to a incorrect watt hour figure. This incorrect watt hour figure is only evident when the piclog is recording small fantom current values, like during a calm day when the windmill is stationary. There are 2 fixes, which I'm implementing in this version of the Piclog. One fix is to average the readings out over a period of time, and log this average reading. This Piclog will record about 45 readings over a 1 minute period, average the figures and record the result. The other fix is to ignore flutuations below a certain value within a certain period of time. The software will reject any amp readings less than 500mA that are less than 30 seconds long. So any little flutuations on a calm day are ignored. Hi Pete. I'm using two separate circuit boards for the PicAxe and powersupply. The powersupply is fed with 24v ( battery ) and supplies 12, 5, -15 and +15. The 12v is needed for the 12v to 15v-0-15v inverter. Yes, its something I had lying around. 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 |
Hi Glenn, I have the Alegro current transducer on my windmill logger and the resolution is approx 25mA per ADC count. I average 2 readings in the picaxe before transmission, for all data except RPM and windspeed. I also check for zero, or null data, and ignore this for any readings. I count the number of successful readings between log intervals, and divide the accumulated totals for each channel by the number of successful readings, to give the average. If there were no successful readings during this period, I store the previous successful readings. This prevents zeros in the data set, and makes graphing more sensible. I still get periods when the logging stops, but then restarts. I think there are issues with timing and the number of logging programs I am running. Gordon. become more energy aware |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Today I discovered if you take a 20X2 chip and feed it 24 volts instead of the recommended 5 volts, it makes a little pop noise and smells bad. 
Lucky I ordered 2 eh! 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 |
Hi Gizmo, did you get to catch some of the magic smoke. I prefer to use a 5V plug-pak for the power supply, or at least a DC-DC converter. I order in pairs as well. You never know what may happen with a proto board. I have a couple of 08M's with one input faulty, possibly from being hit with too high or low a voltage as well. Gordon. become more energy aware |
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| vasi Guru Joined: 23/03/2007 Location: RomaniaPosts: 1697 |
Hi Glenn  ,
I have a french friend which never burned a PIC - I'm not that lucky. I burned a 16F877A on breadboard because I counted wrong his pins and I displaced Vcc and GND connections with 1 pin - it was at first probe and never worked, still tried it few times in different days (and I'm still tempted to try it again). I burned my 08M and crippled another 12F675 - until now. I hope to have time for others
Vasi Hobbit name: Togo Toadfoot of Frogmorton Elvish name: Mablung Miriel Beyound Arduino Lang |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi Glenn, I bet the magic words got out along with the magic smoke.  
I too have a nice collection of axe chips with various dead pins and a red texta line across them. Keep telling myself i might find a use for them one day?? (7 and 17 pin chips) Should it happen again and you need a chip or 2 quickly i have 10 here so give me a call and i will stick it in the post 4 you. I thought only i done silly things like that
Welcome to the magic smoke club.....You have passed your induction. Pete. Sometimes it just works |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
OK, the mega-Piclog lives again. After sorting out some non-linear voltage readings ( See - Measuring voltage with a Picaxe ), I'm pretty happy with the way its performing. There are a few small issues I want to sort out, but nothing that will stop the project from proceeding. 
There is a dump load, but no pictures of that. Its basically a old PC tower case with some fans and a dozen 50 watt down lights mounted inside. Phill has finished the wind turbine, its ready to fly. 
And he's also finished the rectifier and voltage doubler, looks good. 
This is the site. The windmill will mount to a tower, not shown, that will mount to the corner of the shipping container to the right. The guard rail is to keep workers away from the tower and turbine, its only going to be a couple of meters above the container roof. 
The containers contain a BioChar burner, a self powering charcoal factory. You feed in organic waste and out comes charcoal to use in the field. More on that later. 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 |
Hi Gizmo, you can come around and tidy up my wiring anytime. Looking good. Gordon. become more energy aware |
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