bryanf@fluke.UUCP (Bryan Faubion) (04/22/86)
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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
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*******
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) 356-6213fwb@siemens.UUCP (04/28/86)
> 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? > ... > Bryan Faubion; John Fluke Mfg. Co MS 243F; PO Box C9090 Everett WA 98206 iNTEL has a product called BITBUS (tm iNTEL) which uses RS485 for its electrical interface. The data link control is SDLC. Higher level protocols are defined by iNTEL. Get in touch with your local salesman for more info. ----------------------------------------------------- Frederic W. Brehm (ihnp4!princeton!siemens!fwb) Siemens Research and Technology Laboratories 105 College Road East Princeton, NJ 08540 (609) 734-3336 -----------------------------------------------------
wsr@lmi-angel.UUCP (Wolfgang Rupprecht) (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