Hans Parkmann said: > Hello owfs-users and developers, > hi
> I just, registered to this mailing list. I am the one who had the > questions on "stepper driving with owfs", Paul was so kind to post them > here. > I too have been playing with stepper motors and relay control using owfs, so I am curious to see your results. > I got my DS9490R from Dallas today and I got it running with owfs > (latest daily package) under gentoo. I can mount it as root and acces > the bus as user. > Note: It took some research how to pass the "-x" command to fusermount , > I use fuse 2.2 pre 3 and --fuse-opts"allow_other" did the trick for me, > there should be some advice in the faq that tells you how to pass the > option correctly according to the fuse version used. I run Gentoo Kernel > 2.6.10 > > I plan to use the one wire bus mostly for environment control > (Terrarium) and as timer. > At the then the bus weight will be around 30m-40m with around 6-8 > sensors (Temperature, humidity, light) 6-7 relais, and one 12v stepper > motor. Is standard telephone cable still good enough for this cable > weight? Or should I go with cat5 cable ... its all in the cable > according to the dallas application notes ;) > I have a mixture of setups here, but one 1-wire lan that is used 24/7 (actually it's 4 18B20's are polled every minute and the temperature data is feed to a mysql backend) uses only cheap 3-core microphone cable that runs about 20-25 meters long. That setup has never given me problem and has run for over a year. But I'm sure good cable makes a difference, cat5 would have to be the best for the job. > So far I only got the sensor readout working. I write my applications in > Gambas what is a kind of Virtual Basic (please dont throw stones on me), > its not C, but very easy to learn. The only programming experience I > have is qbasic to for me its a gigantic step forward. > I started with basic, then gwbasic, then qbasic, then visual basic. I found the next easy step from basic was perl, and from perl it was (sort of) easy to jump into C. Give perl a shot - its a lot like basic! > The next step will be relais control, I will use DS2408 for this , > someone mentioned I should use logic 0 the switch instead of logic 1. > Why is it better this way? > The final output from the chip will be inverted from the command you give, so echo 0 > owfs will actually give a high or 1 at the chip level (dont ask me why, i dont know) > I finally understood how an optokoppler works (my electronic knowledge > is still very basic, 3 innocent optokopplers went up in smoke but now I > know how they work), the relais are very simple : BC517, CNY17-2, LED, > Resistor, some diodes, I would connect everything this way : > > 1.PIO PIN goes LOW > 2.Optokoppler transistor switches > 3.Collector Emitter voltage connects to BC 517 Base Voltage > 4.BC 517 switches and power is going through the Relais > > This circuit was tested (without DS2408 just some wires and powersupply) > and I hope it will work, it will be tested tomorrow but if you think > anything should be done different please post it. > When the Relais run I will investigate the stepper control further... > personally i dont think you need optocouplers for the relays unless its a really noisy enviroment. I use a DS2480 feed to a 74HC573 latch controlled by a DS2408 (feed the 573 a low to enable the outputs, a high puts the 573 in off, or high-impedance on the inputs and holds the outputs, so another DS2408 can enable another 573 running from the same DS2480 chip. (cool eh?). On my test board the outputs from the 573 go to a ULN2803 buffer IC, this chip can sink 500mA(@12Vdc) from each output - perfect to drive a relay! (or even a stepper motor directly). By the way, I have posted a photo and some details of my test board to a site of mine. http://www.onlinetractorparts.com.au/rohbags/1wire/1wirelan.html Anyway, the point of my email was to ask if you've tested the speed, or response time of your 1-wire lan to see if its suitable to drive a stepper motor. Maybe its just my setup here (although i have two seperate 1-wire lans here) but I find the 1w just isnt quick enough to drive a stepper motor. I mean it can certainly move something that dosn't have to respond the instant you send the command (ie wait 1-2 secs) , but say if you wanted to control a robotic arm or something similar, the lag would be too much. Let me (us) know how it works for you. > My final and most important question : > > On the DS9490R there are two Grounds : "1-wire GND / Return" and "power > ground" > I assume power ground is for the is the gnd for the +5V stolen from the > USB Port, so I wont need this. > > But when I use an external power supply to power the sensors / IO chips, > do I have to connect 1-wire Ground even when i already have connected > the gnd pin of the chip to the GND of my power supply? > I mean when the ground wire from my power supply and 1-wire ground are > connected to the same pin could this harm my Adapter or USB Port? The > power Supply will power all Bus devices(5v), relais(5v) and 3 PC > Fans(12v) so I am afraid this could do damage to the port. > If I was you I would consider using an external power supply for such a setup. Unless the fans and relays are under heavy load I cant see you exceding 500mA, a 1A supply should be plenty to expand with. Make sure you fuse the 5v and 12v if the cable runs will be external anywhere, or if you think there is any chance of damage to the cable anywhere. Just to be safe fuse them both anyway! (I'm sure a simple fuse has saved my circuits, and possibly even a motherboard or two when I jimmy power from the pc. Trust me on this, a heavy load or even a short circuit on the 1-wire lan will damage the controller chip and hard reset the pc the power has been stolen from (and sometimes the pc wont boot up again untill you unplug the mains power, wait 10 secs, and plug it back in), a fuse will stop that (as small as possible, I use 100mA and 250mA "quick-blow" fuses for the 5v and 12v rails.) > Thanks for all your help, this mailing list is really helping, without > it I would still sit here and wonder why I cant access my USB-dongle :) > lol, yeah I've been there before! > Thats all for now, please forgive my poor english I am german. > Simon > Actually your english is pretty good. I'm Australian so we don't care about proper english anyway - half broken sentences are fine! (lol). -- Rohan. ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. 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