On Tuesday, May 22, 2012 05:25:01 AM Rafael Skodlar did opine: > On 05/21/2012 09:15 AM, Jon Elson wrote: > > Rafael Skodlar wrote: > >> On 05/20/2012 12:12 PM, Dave wrote: > >>> On 5/20/2012 12:40 PM, Rafael Skodlar wrote: > >>>> I wonder what kind of power and data cables would you recommend for > >>>> use in X-Y-Z CNC about 1.2mx1m size? Besides power, it's not clear > >>>> to me how many data lines for sensors, encoders, motor control, > >>>> etc. are needed in general. > >> > >> I'm well familiar with flexing and shielding issues in general since > >> early HP plotter days. I was hoping to get a simple answer based on > >> real life experience, get this or that cable with x number of > >> shielded and stranded or twisted wires ;-) That's why I mentioned > >> size as that would give one an idea of motor sizes and other > >> requirements. > >> > >> Is it better to have one cable with x number of wires to take care of > >> all needs or a number of smaller cables (y) with x/y wires? > > > > With non-filtered motor drives, it is pretty important to NOT put > > encoder or other signal-level > > wires in the same cable as the motor wires. I usually separate > > encoder, home/limit sensors > > and motors on 3 cables per axis, even though my motor drives ARE > > filtered. A plain quadrature encoder needs 4 wires, if it has index > > then 5. If differential, > > then 6 or 8 wires. If brushless motors are used, those usually need > > Hall sensors, > > add 4 more wires. Stepper motors need a minimum of 4 wires, brush > > servos need 2 plus maybe a safety ground, brushless would need 3 plus > > ground. > > > > You can check the catalogs for the number and size of the wire > > strands. The more fine > > wires there are, the better the cable will handle flexing. The good > > stuff has #36 AWG > > or finer strands, thinner than hair. > > > > Jon > > Thank you very much for detailed advice to all of you that responded to > my question. I received enough material to spend a few evenings doing my > homework. It's much easier to start knowing what others have tried and > what works in different circumstances. > > Using Cat-5 was a surprise to me as it's a bit stiff unless each wire is > made of even smaller wires, not common in general use.
Solid single strand cat5 can be amazingly durable. I have have a piece about 35 feet long, suspended by black tie-wraps from an eyelet on each end, from the back corner of my back porch roof, to the apex of a 12x16 shed I have some of my machines in, since about 2001. Blowing in the wind, which 2 years ago this June 23th, peaked at 112 mph and took down 3 mature pine trees and part of my houses roof, about $10K State Farm wrote a check for, but that piece of cat5 hasn't dropped a byte. When I put it up, I fully expected to have to replace it annually so I am pleasantly surprised. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> Dyslexics have more fnu. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
