bryanf@fluke.UUCP (Bryan Faubion) (04/22/86)
[] I'm looking for information on RS485 networks that connect industrial input-output devices. RS485 is an electrical standard for a multidrop, balanced, twisted pair, transmission medium (like RS422). Is anyone aware of a standard network protocol, defacto or otherwise, for using this medium? I'm not looking for a big, complex packet switching protocol, rather what I need is a fairly simple protocol that would not place a heavy real time processing burden on a microprocessor. All of the devices on the net do not need to communicate with each other, only to a single bus master. Any leads would be appreciated: names of companies using RS485, pointers to standards, part numbers of microprocessor peripherals, etc. Thanks, ******* Bryan Faubion; John Fluke Mfg. Co MS 243F; PO Box C9090 Everett WA 98206 {uw-beaver,decvax!microsof,ucbvax!lbl-csam,allegra,ssc-vax}!fluke!bryanf (206) 356-6213 -- ******* Bryan Faubion; John Fluke Mfg. Co MS 243F; PO Box C9090 Everett WA 98206 {uw-beaver,decvax!microsof,ucbvax!lbl-csam,allegra,ssc-vax}!fluke!bryanf (206) 356-6213
wsr%lmi-angel@lmi-angel.UUCP (04/29/86)
In article <> bryanf@fluke.UUCP writes: >I'm looking for information on RS485 networks that connect industrial >input-output devices. RS485 is an electrical standard for a multidrop, >balanced, twisted pair, transmission medium (like RS422). I remember seeing something like that from Corvus. They called it 'Omninet'. It had normal sync usarts linked over a multidrop, +/-5v balanced line (at 1Mbaud). Their protocol was all proprietary, so it probably isn't a very good starting point. The Apple Mac-bus is another similar bus, although they use transformer coupling to the two-wire serial cable. A request to net.micro.mac should provide lots of info. -- Wolfgang Rupprecht {harvard|cca|mit-eddie}!lmi-angel!wsr