Long distance serial network
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I am working in a project that will use around 100 Stamps or PICS
connected in parallel network architecture, distributed over a 3 Km
underwater. Cable should be a PVC unshielded 3 or 4 conductor 1.5mm
section( 2 for power VDC and 1 or 2 for data communications ).Normally
all processors will be waiting and hearing the line. Master unit at one
end and at predetermined times will call an addressed processor to
collect data and send it out over the same line. Then will ask another
processor.
I will appreciate any comments and suggestions specially about the
feasibility and reliability of such serial communication.
0-5V will work? (3wire cable) or should I use a differencial driver chip
like a MAX485 and a 4 wire cable ?
What may be the max expected serial baud rate ? 4800? 9600 ? 19200?
Thanks for the input.
ACJacques
connected in parallel network architecture, distributed over a 3 Km
underwater. Cable should be a PVC unshielded 3 or 4 conductor 1.5mm
section( 2 for power VDC and 1 or 2 for data communications ).Normally
all processors will be waiting and hearing the line. Master unit at one
end and at predetermined times will call an addressed processor to
collect data and send it out over the same line. Then will ask another
processor.
I will appreciate any comments and suggestions specially about the
feasibility and reliability of such serial communication.
0-5V will work? (3wire cable) or should I use a differencial driver chip
like a MAX485 and a 4 wire cable ?
What may be the max expected serial baud rate ? 4800? 9600 ? 19200?
Thanks for the input.
ACJacques
Comments
connected in parallel network architecture, distributed over a 3 Km
underwater. Cable should be a PVC unshielded 3 or 4 conductor 1.5mm
section( 2 for power VDC and 1 or 2 for data communications ).Normally
all processors will be waiting and hearing the line. Master unit at one
end and at predetermined times will call an addressed processor to
collect data and send it out over the same line. Then will ask another
processor.
I will appreciate any comments and suggestions specially about the
feasibility and reliability of such serial communication.
0-5V will work? (3wire cable) or should I use a differencial driver chip
like a MAX485 and a 4 wire cable ?
What may be the max expected serial baud rate ? 4800? 9600 ? 19200?
Thanks for the input.
ACJacques
I've built a similar system (off topic? not BasicStamp!) using RS485. It
was overland, linear, 1Km long, 2 wires for feeding, 2 wires for data, 44
measuring stations, 1 PC cyclically receiving data from addressed stations
according to a software schedule. This has been working faultlessly for
more than 3 years in desert conditions. RS485 lines are supposed to stretch
to about 1200m but there are boosters which can extend this length and 127
units can easily be individually addressed.
I hope this is of some help.
Dov Yassky
Original Message
From: "A.C.Jacques" <acjacques@i...>
To: <basicstamps@egroups.com>
Sent: Tuesday, July 25, 2000 4:51 PM
Subject: [noparse][[/noparse]basicstamps] Long distance serial network
> I am working in a project that will use around 100 Stamps or PICS
> connected in parallel network architecture, distributed over a 3 Km
> underwater. Cable should be a PVC unshielded 3 or 4 conductor 1.5mm
> section( 2 for power VDC and 1 or 2 for data communications ).Normally
> all processors will be waiting and hearing the line. Master unit at one
> end and at predetermined times will call an addressed processor to
> collect data and send it out over the same line. Then will ask another
> processor.
> I will appreciate any comments and suggestions specially about the
> feasibility and reliability of such serial communication.
> 0-5V will work? (3wire cable) or should I use a differencial driver chip
> like a MAX485 and a 4 wire cable ?
> What may be the max expected serial baud rate ? 4800? 9600 ? 19200?
> Thanks for the input.
>
> ACJacques
>
>
>
>