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Ttelmah
Joined: 11 Mar 2010
Posts: 19498
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 Posted: Fri Apr 18, 2014 2:10 pm |
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The old 'rule of thumb', is RS485 can manage 10^8 bps*distance in metres.
10000000/10000 = 1000m
It is going to be stretching things a little. Especially since distances always end up being further than you expect.
Unless the environment is fairly nice, possibly easier to look at a wireless solution. The protection needed to cope with lightning etc., at this sort of distance with a wired solution is going to possibly get quite interesting.
Best, direct solution, cheap fibre optic... |
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temtronic
Joined: 01 Jul 2010
Posts: 9221
Location: Greensville,Ontario
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| Posted: Fri Apr 18, 2014 2:54 pm |
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Have to agree about lightning protection ! It was always 'fun' seeing the 'computer guys' replacing modems, PCs, etc. after a 'nearby' lightning strike while my energy management system kept on communicating. You also need to figure out how to detect 'little things' like backhoes digging up wires, cars destroying poles, ONE busted wire, etc. Real world stuff..NOT taught in classrooms....
Wireless seems to be very,very popular but be wary about code 'overhead' and be sure no one can 'hack' your system. 20+ years and no one can figure out how my system works with just one wire.
hth
jay |
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ezflyr
Joined: 25 Oct 2010
Posts: 1019
Location: Tewksbury, MA
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| Posted: Fri Apr 18, 2014 3:39 pm |
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Hi All,
Call me a cynic, but this project sounds like a 'wild goose chase' to me. Come on, a 'newbie' programmer, and their first project right out of the chute is a network spanning 1.3KM (0.8 mile), with PIC's??? I'd sure like to hear more about the intended application for this one! Frankly, just about everything about this thread sounds 'odd' to me! If I had a project like this, I think that the ultra-long distance nature of the project would be one of the first things I mentioned. An item of this importance would not / should not have to slip out in response to a question..... Again, I think this is some pie-in-the-sky fantasy project that will never get implemented!
John |
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mariemee12
Joined: 16 Apr 2014
Posts: 7
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| Posted: Sat Apr 19, 2014 12:49 am |
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i told you what i want .. i just have a problem with the communication uart between the 2 pic .
in all cases thank all .. i gonna find some examples  |
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Mike Walne
Joined: 19 Feb 2004
Posts: 1785
Location: Boston Spa UK
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| Posted: Sat Apr 19, 2014 3:01 am |
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| mariemee12 wrote: | i told you what i want .. i just have a problem with the communication uart between the 2 pic .
in all cases thank all .. i gonna find some examples |
You are not telling us what your UART communication problem is.
Is it hardware or software?
What kind of messages do you want to pass from the 18F to the 16F?
What kind of messages do you want to pass from the 16F to the 18F?
What does each PIC do with the messages?
As a test only you could use a MAX232 on each TX line and send all messages to a PC via RS232 to USB links.
Display all the messages in separate windows on the PC.
That way you will be able to 'listen in' on all the comms.
Mike |
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temtronic
Joined: 01 Jul 2010
Posts: 9221
Location: Greensville,Ontario
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| Posted: Sat Apr 19, 2014 4:53 am |
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Mike is 100% correct about using the MAX232 ! By breaking down the project into 'segments', you'll be able to use a PC/terminal program to verify each 'segment' work properly.
After that you'll be able to insert your 1.3Km of wire and the project will be 100% 'up and running'
hth
jay |
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