You are right, pushing high speed signal over long distances is not an easy task. It is no coincidence that the faster electronics are also physically smaller. With a given technology the way to go faster is to get smaller. This applies to CPU chips and also cables.
On Sat, Dec 24, 2016 at 1:44 PM, Bertho Stultiens <ber...@vagrearg.org> wrote: > > On 12/24/2016 09:59 PM, Chris Albertson wrote: > > Read the little write up at the Mesa site about cable length. They > > claim ribbon cable is the worst and to only use it for very short > > runs, 2 or 3 feet at most. They suggest using "real" parallel > > cables made with twisted pairs and shielding for longer runs. Using > > one of their fancy IEEE cables you can go up to 25 or 30 feet, half > > that with a normal round cable and half that again with ribbon > > cable. > > You are right, ribbon cables are not very good at carrying signals over > long cables. They will pick up too much noise if not shielded and suffer > often from significant cross-talk if too long. > > The "standard" old-school printer cables (the round ones) are often > shielded and twisted pair, which are actually quite good. You have to be a little careful. Most round cables you buy today say "IEEE 1284" and these are the ones that allow data to go up to 30 feet at up to about 2MHz. But this assume good driver/buffers and old style 74xx logic chips. The really old cables or those you make yourself are good for maybe 1/2 these specs. But IEEE 1284 is so old almost anything sold as a "parallel printer cable" will be made to this spec. But not so for old "junk drawer" parts. So there is "old school" and "really old school" you have to check what you have I would start by testing with signals below the KHz range. Maybe 100 steps per second on one axis. -- Chris Albertson Redondo Beach, California ------------------------------------------------------------------------------ Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today.http://sdm.link/intel _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
