Right now I design away from Ethernet within machine because with my computer and switches and it does not work perfect. Whatever the reason is I simply can't do anything about it.
On Thu, 1 Jun 2017 10:32:27 -0700 Chris Albertson <[email protected]> wrote: > Modern Ethernet does not have a collision problem. It uses a switched > topology. All of the cables are point to point. One end is on your device > the other is on a switch. The switch has enough performance and bandwidth > to drive all cables at full wire speed. > > The switch adds very little latency. Modern switches (if they can) do not > buffer the entire Ethernet packet as the older first generation switches > did. They now will read the packet header and pick off the "to" address > then cut the bits over to the correct outbound cable. > > For sending data to 18 different motors, Ethernet would work fine, Use a > 24 port switch. > > I have a small robot arm that is controlled by 7 channels of PWM. I use a > single chip device that has 16 PWM output pins and uses i2C input. Cost is > under $5 It would be easy to use two of these chips but the resolution is > poor I can control the PWM duty cycle only to about one part in a > thousand. The over the bus protocol is defined by the chip maker and I > have no choice but to use that. > > > > On Thu, Jun 1, 2017 at 12:04 AM, Nicklas Karlsson < > [email protected]> wrote: > > > > If Ethernet is "complex" then PowerLink is "very complex" as it is a few > > > layers over top of Ethernet. > > > > > > Is there a list of requirements some place? What are the end points, > > > processes that run on a CPU of some kind. > > > > > > I've been doing this kind of work for ages but you can't select anything > > > without a detailed set of requirements > > > > It is rather simple to send or receive via UDP/IP or TCP/IP for example > > via Ethernet. UDP/IP is one way packets. TCP/IP send acknowledge which add > > bandwidth requirement in the opposite direction. To make sure packets > > within a particular time period may however be harder. > > > > Then sending point to point over an ordinary serial channel like UART or > > SPI data usually arrive practically instantly and there are no collisions. > > UART or SPI is also very cheap. Software for simple point to point may also > > be very simple. A bus have huge advantages then it come to number of nodes > > but there may be collisions. > > > > Even though collisions are a small problem to make it work perfect during > > periodic communication may be surprisingly hard while for a simple serial > > channel it is no problem at all. > > > > > > Regards Nicklas Karlsson > > > > ------------------------------------------------------------ > > ------------------ > > 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 > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > -- > > Chris Albertson > Redondo Beach, California > ------------------------------------------------------------------------------ > 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 > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
