Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!smc!hendel
From: hendel@smc.smc.COM (Ariel Hendel)
Newsgroups: comp.dcom.lans
Subject: Re: Serial Multi-drop network info wanted
Summary: Low cost networking for real-time systems
Message-ID: <166@smc.smc.COM>
Date: 17 May 91 18:11:41 GMT
References: <31099@rouge.usl.edu>
Distribution: usa
Organization: Standard Microsystems Corp., Hauppauge NY
Lines: 43



Subject: Re: Serial Multi-drop network info wanted
In-Reply-To: your article <31099@rouge.usl.edu>
News-Path: uunet!spool.mu.edu!rex!rouge!rouge.usl.edu

> I am working on a project which needs to connect a bunch of manufacturing
> machines to a PC. The PC acts as a cell-controller for the manufacturing
> machines. Our prototype implementation was a hacked rs422 thing. We are
> now moving into a real implementation phase so i need to get educated
> about real multi-drop networking standards. Ideally the protocol would
> be cheap to implement, be able to run over twisted pair, and be able
> to communicate with the PC through the PCs serial port. 
> 
> Can someone please steer me in the right direction so I can get educated?
> Thanks
> -
> patrick
> pml@cacs.usl.edu

We are addressing the manufacturing and industrial control with a special
Arcnet controller that has the following characteristics:

- 24 pin controller with 2kx8 RAM on-chip.
- Runs the token passing Arcnet protocol at 2.5 Mbps (or less).
- Interfaces micro controllers as well as CPUs.
- Supports RS-485 multidrop networks for 20 nodes/700ft.
- Provides deterministic access and flow control to the network.

It looks like a UART from the interface point of view, but it gives you
the lower overhead and expandability of a peer to peer packet switched
network.
The device number is 20020.
If it looks like a relevant approach, there is literature you could get,
as well as an 8051 based evaluation system.

Hope it helps.

Ariel Hendel
Standard Microsystems Corp.
(516) 273-3100
uunet!smc!hendel