Is 100BaseT ethernet full duplex? (I think it is.) In principle, one could make a "hub" (not technically a hub) that daisy chained cables. So, the master would output to slave 1 abd input from slave N. Slave 1 would input from the master and output to slave 2. Slave 2 would input from slave 1 and output to slave 2... Slave N would input from slave N-1 and output to the master.
Each slave would read its input, process it if appropriate and pass it on to the next in the link. It would also inject its output into the ring. Think of it as a token ring using ethernet hardware that is cheap and readily available. The master would continuosly send poll packets around the ring. An alternative is to use a standard hub and have the master poll each of the slaves, in turn. I don't see this as something to use with encoders, but I could imagine its being used with smart motor controllers or multi-axis controllers (like Jon's). Ken [EMAIL PROTECTED] Mark Kenny Products Company, LLC 55 Main Street Voice: (888)ISO-SEVO (888)476-7386 Newtown, CT 06470 Fax: (203)426-9138 http://www.MarkKenny.com -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Peter C. Wallace Sent: Monday, October 29, 2007 2:16 PM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Ethernet I/O On Mon, 29 Oct 2007, Alex Joni wrote: > Date: Mon, 29 Oct 2007 21:00:22 +0200 > From: Alex Joni <[EMAIL PROTECTED]> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Ethernet I/O > >> Umm, no... As master, no problem but slaves will be expensive: >> >> Ethercat slaves require either custom proprietry hardware or proprietary >> IP > > Hmm, unfortunately I can't argue there.. been trying to find some prices for > a slave chip. > I found some products, but no prices anywhere: > - beckhoff ET1100, ET1200 > - ESC10, ESC20 > and some FPGA IP Core for Altera & Xilinx > > Maybe you have an idea how expensive they are? No, I looked into this several months ago but was discouraged by the hardware requirements. For the sychronization standards, I have more faith that IEEE 1588 will get embedded in more Ethernet chips and processors with Ethernet, for example: Ethernet Transceiver with IEEE 1588 PTP Hardware Support from National Semi (Product News, 17 Oct 2007 ) National Semiconductor has introduced its Ethernet transceiver with integrated hardware support for the IEEE 1588 Precision Time Protocol (PTP). For applications in motion control, instrumentation, data acquisition and telecommunications, the DP83640 precision PHYTER transceiver synchronizes the distributed network nodes to a master clock with 8-nanosecond accuracy. The model DP83640 precision PHYTER transceiver synchronizes distributed network nodes to master clock with 8 nsec accuracy and offers 100 Mb synchronous Ethernet mode that eliminates any inaccuracy caused by clock drift between nodes. It integrates hardware time stamping of receive and transmit packets, high-accuracy IEEE 1588 clock, and 12 GPIO pins that handle simultaneous real-time events/multiple triggers. Device interfaces with any microcontroller, FPGA, or ASIC with Ethernet MAC. The samples of the DP83640 transceiver are available now in a 48-pin LQFP. The DP83640 will be priced at $5.24 each in 1,000-unit quantities. > > Regards, > Alex > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
