On Saturday 22 October 2016 09:09:47 Erik Christiansen wrote: Msg marked FFR.
> On 22.10.16 07:26, Gene Heskett wrote: > > 2nd Q is only semi-related, but I can get, from gearbest, an arduino > > mega r3 with a pile of 10 bit analog inputs for a tenner. See: > > > > <http://www.gearbest.com/development-boards/pp_18651.html> > > The ATmega2560, with 256 kiB of flash, is overkill for a simple > monitor, a cheaper UNO is ample, and a bit smaller. The UNO uses the > ATmega328P, which is the most common Arduino CPU, especially at the > modest end. (Which may increase the chances of finding some > off-the-rack software which does most of what you want, and needs less > porting¹.) > > I haven't used the USB on the UNO for communication by the > application, but it's no biggie: > http://www.ladyada.net/learn/arduino/lesson4.html > > > Which, if it can talk to linuxcnc over the usb cable, might be able > > to warn me if the motor is being lugged excessively and getting too > > hot since its quite well out of sight and mind where its hung. > > Theres a lot more it could do, I just haven't conjured up the use > > scenario yet. :) > > That could be a monkey trap though, - a feast of specification creep, > and it's so easy to topple into a pit of lots of little bits to > develop, both firmware and hardware. OK, it's easy to hook up e.g. a > LM335s to a couple of analogue inputs, and cobble up an analogue front > end for measuring power, e.g. > > http://meettechniek.info/diy-instruments/arduino-wattmeter.html > > The code at: > http://meettechniek.info/diy-instruments/arduino-wattmeter-code-v1-0.t >xt might be an adequate seed corn for your sampling application. > > > But, mpja.com also has a $2.49 module #31588-MP, that could send an > > overheat alarm bit directly to a gpio pin on a 5i25 & that looks a > > lot simpler to do. Since these spindle bearings are bronze, an > > overtemp alarm on each because they've not been lubed recently could > > also be handy. > > And in the same vein, a comparator on a current shunt can drive > another pin when motor current goes too far north. The vfd seems to have its own current regulation built in, I've had it down to 5hz and while the motor heats and doesn't run very smooth, but the amprobe reading isn't alarming. OTOH, the amprobe could be lieing like a rug at that reduced frequency. I'd just set a lower limit that it could do for an hour at a time & still lay a hand on it running no load. With the drag of the machines spindle bearings etc, I don't think that 20 hz is at all realistic, so before I stick it away, I'll reset the minimum to at least 30 hz. > > Is such an effort worth it? > > KISS, 'cos there are too many projects for anyone to finish them all. > (Except when the journey is the object. ;-) > Chuckle, and point taken. I was just thinking that since the motor is laying on my table saws table, its in an ideal location to get one of those $2.49 ntc type temp sensors stuck to it with some sili-goop. > ¹ I program my ATmegas in 'C' and assembler, having never tangled with > that "sketch" stuff, so peripheral hardware variations across the > ATmega variants can be a bit more intrusive, perhaps. C I have experience with, altho I've not kept up after the Amiga's were retired, and gobs of assembler but all thats on 30 yo 8/16 bit Motorola 6809's, and the even schmardter Hitachi 6309's and even earlier, RCA 1802's. No assembler there except me, looking up the the nemonic and entering the hex for it on a hex keypad. > Erik > (Who last night had a 40m high 1.8m wide Redgum fall across the creek, > the road, my driveway, and the front garden, ending 8m from the > bedroom window. yiiks, That would have plumb ruined the rest of the nights sleep, > It was after midnight, so I went back to sleep without > looking. It was a quite sufficiently frightful mess this morning, but > a council crew with chainsaws and excavator sliced, diced, and packed > it all into three truckloads in four hours. I wouldn't have had it > done in a week. The trunk that came across the drive was only 1m in > diameter, but still a lot of dicing. And the mess of branches, Oof! > Oh, and a 60 cm diameter, 20m high Stringybark fell in the back yard > the night before. Even after the high winds, the 146 mm of rain in the > last 3 weeks is too much for the eucalypts to hold well in the soggy > clay, with no taproots.) > You are lucky the local gvmnt helped. Around here, such is 100% up to us to clean up. And we've had close to 100mm of rain here in the last week, but our clay was so dry the cracks were 25mm wide, so it just went in like there was a vacuum cleaner running in the bottom. I don't think the cracks are 100% closed up yet! Thanks Eric. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
