> Hardware for master is hard to find because you don't need it. Any normal > Ethernet port works. Master is a software-only solution.
Time triggered transmit would be useful to get perfect timing and fully utilize bandwidth. > You can choose a simple less redundant network topology. Double ring is > used because it can tolerate failure and it's not more expensive then daisy > chain. Double ring is two daisy chains in opposite direction and I expect it to two almost twice as exensive except the cables. Even though I do not use I can't find a chip with only direction one direction. The Ethercat cost somewhere in between 2-5 times as much as a micro controller for the hardware which would be a problem for a low cost product but for me and probably most other quality is more important. Most important is working principle similar to cascade coupled shift registers, it's simple and there are no collisions. Principle is similar to cascade coupled shift register, I guess at each node last value shifted out would be the CRC checksum. Micro controller with CRC hardware for SPI would probably handle this but with limitations on where data is inserted and not the least no differential signals. Even though Ethercat chip is relatively expensive compared to other components I will pay the money because in the large picture it's little money. Because of this they might have created something that could earn them very good money. 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
