Very Computer

I have not used Fieldbus, but have used a lot of Echelon LonWorks.
The technology is designed for one Echelon Neuron Chip (being made by
Motorola and Toshiba) to talk to one or more other Neuron Chips
through some physical media.  LonWorks interfaces directly to the
physical layer (OSI Layer #1) which can be over almost any type of
media.  Echelon has designed several different types of transceivers
as has many of their users.  Some of the transceivers currently
available are:
        EIA-485 Twisted Pair Transceivers
        Transformer Isolated Twisted Pair Transceivers
        Free Topology Transformer Isolated Twisted Pair Transceivers
        Spread Spectrum Power Line Transceivers
        RF Transceivers
        IR Transceivers

There are also several types of gateways available to go between the
LonWorks Network and other common Control and Data Networks.  If you
are interested in more specific info, Echelon has a good LonWorks Web
site at:
        http://www.lonworks.echelon.com/

Good Luck.

Bob Harvey

San Diego, CA  USA

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An:      
Betreff:

------ Physical Layer of fieldbuses ---------

LON  (Echelon .. )
             Media                 Speed         max. distance
             RS 485                 39k               1200 m
             tranf. coupl.          78k               2000 m
             tranf. coupl.        1,25M               500 m
             dir.    coupl.       1,25M                30 m
             and other

PROFIBUS  (Allen Bradley, Siemens ...  )
             Media                 Speed         max. distance
             RS 485                9,6k-               1200m -
                                    12M                 200m
                                    500k                200m       (DIN FMS)

InterBus-S  (Phoenix Contact, Weidmueller ... )
            Media                 Speed         max. distance
            RS485                 500k               13,2 km

CAN     (Selectron, CAL, DeviceNet, SDS ... )
            Media                 Speed         max. distance
            RS 485                  50k              1300m
                                 1,2 M                100m

-------  Ranking by  speed / responsetime -------
InterBus-S         2048 signals / 2ms     ( min. cycle time: 0.5 ms )
PROFIBUS           1952  signals / 8 -10 ms for  500k / FMS, FDL.
                    256  signals / 2ms  for 1,5 Mb/s / PROFIBUS DP
                    256  signals / 0.5ms for 12 Mb/s / PROFIBUS DP
CAN                  32  signals / 2ms
LON                      20-30 ms, depends on media and packetsize

Product situation:

PROFIBUS:  supported by all importent PLC-vendors
(Allen Bradley is offering a complete PROFIBUS productline from
the PLC controllers to remote PROFIBUS DP I/O modules ! )
Stable and realy open protocol standard up to layer 7!
There is a big community of hundreds of different vendors.

InterBus: supported by the all importent PLC-vendors
Stable and realy open protocol standard up to layer 7!
There is a big community of hundreds of different vendors.

CAN: supported by some importent PLC-vendors
Stable and realy open protocol standard up to layer 2!
There are lots of propritary private layer 7 protocols and
so called standards like: DeviceNet, SDS, CAL (next CANopen ..).

LON: used in fully distributed solutions for the sensor /actor area,
mostly not in the industrial automation.
Stable protocol standard up to layer 7, controlled by Echelon, LonMark!

We are supporting all mentioned fieldbuses under QNX 4.2 !

Best Regards
Armin Steinhoff,   STEINHOFF Automations- an Fieldbus Systems

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