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Serial to Ethernet Conversion

Hey guys,

I am not wanting to buy an off the shelf piece of hardware to do this.
I want to try and do it myself.

What I want to do is take an RS232 signal and pass it through using
ethernet. I have a car wash vacuum and the timer has RS232. I want to
be able to talk to it over more distance than the 232 will allow.

I think there is an IC that should do this. Im thinking maybe a
pre-programmed microcontroller? Can anyone point me in a direction to
get started?

I dont know a lot about ethernet so this is a challenge that I am
wanting to try and accomplish without buying the already designed part.

Thanks ahead of time.
 
N

Nico Coesel

Jan 1, 1970
0
Hey guys,

I am not wanting to buy an off the shelf piece of hardware to do this.
I want to try and do it myself.

What I want to do is take an RS232 signal and pass it through using
ethernet. I have a car wash vacuum and the timer has RS232. I want to
be able to talk to it over more distance than the 232 will allow.

I think there is an IC that should do this. Im thinking maybe a
pre-programmed microcontroller? Can anyone point me in a direction to
get started?

I dont know a lot about ethernet so this is a challenge that I am
wanting to try and accomplish without buying the already designed part.

Thanks ahead of time.

Get a Linksys NSLU2 and hack it (google for NSLU2 and Linux). There
will be plenty of fun in this project even with buying the hardware.
 
A

Andrew Jackson

Jan 1, 1970
0
Hey guys,

I am not wanting to buy an off the shelf piece of hardware to do this.
I want to try and do it myself.

What I want to do is take an RS232 signal and pass it through using
ethernet. I have a car wash vacuum and the timer has RS232. I want to
be able to talk to it over more distance than the 232 will allow.

I think there is an IC that should do this. Im thinking maybe a
pre-programmed microcontroller? Can anyone point me in a direction to
get started?

I dont know a lot about ethernet so this is a challenge that I am
wanting to try and accomplish without buying the already designed part.

Thanks ahead of time.

Lantronix www.lantronix.com
or
Digi www.digi.com

Make serial<>Ethernet converters (as well as WiFi). They also offer
libraries for virtual serial ports at the "PC", rather than "embedded", end.

Andrew
 
B

budgie

Jan 1, 1970
0
Hey guys,

I am not wanting to buy an off the shelf piece of hardware to do this.
I want to try and do it myself.

Fair enough.
What I want to do is take an RS232 signal and pass it through using
ethernet. I have a car wash vacuum and the timer has RS232. I want to
be able to talk to it over more distance than the 232 will allow.

Why ethernet? What sort of distance is involved? RS232 can travel quite a
distance, or you could convert to a differential signalling mode for even
greater distance.
I think there is an IC that should do this. Im thinking maybe a
pre-programmed microcontroller? Can anyone point me in a direction to
get started?

I dont know a lot about ethernet so this is a challenge that I am
wanting to try and accomplish without buying the already designed part.

Certainly a challenge.
 
F

Fritz Schlunder

Jan 1, 1970
0
Hey guys,

I am not wanting to buy an off the shelf piece of hardware to do this.
I want to try and do it myself.

What I want to do is take an RS232 signal and pass it through using
ethernet. I have a car wash vacuum and the timer has RS232. I want to
be able to talk to it over more distance than the 232 will allow.

I think there is an IC that should do this. Im thinking maybe a
pre-programmed microcontroller? Can anyone point me in a direction to
get started?

I dont know a lot about ethernet so this is a challenge that I am
wanting to try and accomplish without buying the already designed part.

Thanks ahead of time.


I'm sure there are multiple solutions out there available, but the one I am
personally most familiar with is the ENC28J60 by Microchip and available at
Digikey.

http://ww1.microchip.com/downloads/en/DeviceDoc/39662a.pdf

The device communicates with a microcontroller via an SPI interface. So,
this would require a two chip solution, one being the ENC28J60 and another
being a microcontroller with an integrated UART and SPI interface.

If you wait a little while Microchip has plans to start releasing some
microcontrollers with built in ethernet capabilities (Ex: PIC18F97J60 and
it's close relatives), and no doubt at least some if not all of them will
include UART capabilities.
 
D

Donald

Jan 1, 1970
0
Fritz said:
I'm sure there are multiple solutions out there available, but the one I am
personally most familiar with is the ENC28J60 by Microchip and available at
Digikey.

http://ww1.microchip.com/downloads/en/DeviceDoc/39662a.pdf

The device communicates with a microcontroller via an SPI interface. So,
this would require a two chip solution, one being the ENC28J60 and another
being a microcontroller with an integrated UART and SPI interface.

If you wait a little while Microchip has plans to start releasing some
microcontrollers with built in ethernet capabilities (Ex: PIC18F97J60 and
it's close relatives), and no doubt at least some if not all of them will
include UART capabilities.

The OP asked for pre-programmed.

The microcontroller will need some kind of program running.

Not for the faint of heart.

Good Luck

donald
 
R

Rene Tschaggelar

Jan 1, 1970
0
Hey guys,

I am not wanting to buy an off the shelf piece of hardware to do this.
I want to try and do it myself.

What I want to do is take an RS232 signal and pass it through using
ethernet. I have a car wash vacuum and the timer has RS232. I want to
be able to talk to it over more distance than the 232 will allow.

I think there is an IC that should do this. Im thinking maybe a
pre-programmed microcontroller? Can anyone point me in a direction to
get started?

I dont know a lot about ethernet so this is a challenge that I am
wanting to try and accomplish without buying the already designed part.

The most sensible solution would be to use RS422.
One pair per signal wire.

Rene
 
F

Frithiof Andreas Jensen

Jan 1, 1970
0
Hey guys,

I am not wanting to buy an off the shelf piece of hardware to do this.
I want to try and do it myself.

Famous last words ;-)
What I want to do is take an RS232 signal and pass it through using
ethernet. I have a car wash vacuum and the timer has RS232. I want to
be able to talk to it over more distance than the 232 will allow.

Well, if you use optic fiber for the RS-232 then it will go a loooong
way!

The cheap-ish plastic fiber will go for about 1 km, Glass almost as
long as you can get it.
I dont know a lot about ethernet so this is a challenge that I am
wanting to try and accomplish without buying the already designed
part.

Consider what you need.

Protocol conversion is *hard* - if what you mean by "ethernet" is that
the device is somewhere on the Internet then you need something like
XML-RPC to translate from commands <-> HTTP <-> IP <-> HTTP <-> RS-232
(commands).

And infrastructure such as domain names and a computer.

If what you need is a "longer wire" then stick with RS-232 and use a
better electrical interface like f.ex. fiber or current loop.
 
T

Tim Shoppa

Jan 1, 1970
0
What I want to do is take an RS232 signal and pass it through using
ethernet. I have a car wash vacuum and the timer has RS232. I want to
be able to talk to it over more distance than the 232 will allow.

RS-232 is a surprisingly robust - even though the spec might officially
say that you can't exceed "n" feet, you almost certainly can go five
times the official distance and it will work (well, mostly). You may
have to go to a lower baud rate. The next step up is to use
differential RS-422, or to use short-haul modems. All of these are
entirely off-the-shelf solutions.

RS-232 is substantially less robust if real drivers and receivers are
not used (e.g. lots of hobbyist projects where they assume TTL levels
are mostly compatible with RS-232...)

There are good reasons (especially if you have multiple devices and can
actually make use of a real network) to go with ethernet. Otherwise I
would recommend sticking with something simple.

Tim.
 
The reason I chose ethernet was because my car wash's network is
ethernet based.

I have a system where the customer can get a code (from the gas pump at
the neighboring gas station) and enter that code to get a car wash. I
am wanting to put this into affect with the vacuums as well. This way
my customers can use the code to detail their entire car.

The vaccuum manufacturer's timer has the RS-232. The code system I
have has ethernet.

Also the vacs are about 150 ft from the service room where the central
system is located. I didnt want to run RS232 that far.

RS485 would be my choice but I want to use what my system already uses
for the self-serve bays and the automatic.

I know this may seem like a big project. If I cannot do it then I
cannot do it. I am at least wanting to attempt it and at worst all I
can do is learn some things on the way to my failure!!
 
B

budgie

Jan 1, 1970
0
The reason I chose ethernet was because my car wash's network is
ethernet based.

I have a system where the customer can get a code (from the gas pump at
the neighboring gas station) and enter that code to get a car wash. I
am wanting to put this into affect with the vacuums as well. This way
my customers can use the code to detail their entire car.

The vaccuum manufacturer's timer has the RS-232. The code system I
have has ethernet.

Also the vacs are about 150 ft from the service room where the central
system is located. I didnt want to run RS232 that far.

RS485 would be my choice but I want to use what my system already uses
for the self-serve bays and the automatic.

I know this may seem like a big project. If I cannot do it then I
cannot do it. I am at least wanting to attempt it and at worst all I
can do is learn some things on the way to my failure!!

Don't get me wrong, I admire the fact that you're prepared to take on a
challenge like this. But I often have the impression that people conceive one
solution and in so doing disregard the possibility of others which may be
simpler.

RS485 would certainly eat that distance. Back in my days on campus, we ran
RS232 several hundred yards (yep, Australia wasn't metricated then) at 9600
between buildings without drama. But nowadays I'd certainly go with a balanced
line system.
 
The reason I chose ethernet was because my car wash's network is
ethernet based.

Okay, sounds reasonable.

If you are willing to do some software work (learning experience
value), you might look at the MC9S12NE64, which is a microcontroller
from freescale with pretty much an entire ethernet interface (except
the transformer) in it. You will have to take the example ethernet
code though, and modify it to do what you need.

There are some more packed chip/module solutions from connectone which
might save you modifying ethernet code, however you will have to learn
how to configure them.
 
R

Roger Hamlett

Jan 1, 1970
0
budgie said:
Don't get me wrong, I admire the fact that you're prepared to take on a
challenge like this. But I often have the impression that people
conceive one
solution and in so doing disregard the possibility of others which may
be
simpler.

RS485 would certainly eat that distance. Back in my days on campus, we
ran
RS232 several hundred yards (yep, Australia wasn't metricated then) at
9600
between buildings without drama. But nowadays I'd certainly go with a
balanced
line system.
The big question though regarding Ethernet, is 'quantity'. Ethernet,
involves you in having to implement the TCP/IP software part. Now this is
not trivial. Some sections are 'off the shelf', but some are charged for,
or involve a lot of work. You then have to implement the virtual serial
port driver at the other end, or a direct software ethernet drive. There
is also the implementation of the Ethernet hardware interface at the
remote unit as well. If the quantity is less than perhaps 100 off (and
probably more like 500 off), it is going to be significantly cheaper to
use an off the shelf virtual Ethernet serial interface. Such units are
available for less than $100, and the development time/cost of the
hardware/software makes these a much better choice.
It is a much 'bigger' project than I think the poster is aware of....
RS485/422, would definately be the much simpler choice.
I'd suggest the poster have a look at units like the eCov-100, or 115.
There are also Ethernet units, built into assemblies the size of
matchboxes. A search for the EM100, and EM200 modules, might be helpful.

Best Wishes
 
P

Peter Heitzer

Jan 1, 1970
0
Hey guys,
I am not wanting to buy an off the shelf piece of hardware to do this.
I want to try and do it myself.
What I want to do is take an RS232 signal and pass it through using
ethernet. I have a car wash vacuum and the timer has RS232. I want to
be able to talk to it over more distance than the 232 will allow.
Use RS485 oder RS422 which uses differential receivers and transmitters.
Using diffential signalling you can achieve line length of a few hundred
meters and can still use standard uarts.
 
P

Peter Heitzer

Jan 1, 1970
0
Perhaps you are using 10/100 Mbit which requires only 4 Pins of the
RJ45 socket but have a 8 wire cable to each socket. In this case you
could use the 4 wires with RS485.
If you indeed want to use ethernet then do a search for "Ethernut".
 
N

Nico Coesel

Jan 1, 1970
0
The reason I chose ethernet was because my car wash's network is
ethernet based.

I have a system where the customer can get a code (from the gas pump at
the neighboring gas station) and enter that code to get a car wash. I
am wanting to put this into affect with the vacuums as well. This way
my customers can use the code to detail their entire car.

The vaccuum manufacturer's timer has the RS-232. The code system I
have has ethernet.

Also the vacs are about 150 ft from the service room where the central
system is located. I didnt want to run RS232 that far.

150ft? That's peanuts for RS232 at baudrates up to 19200 bps.
 
K

Ken Taylor

Jan 1, 1970
0
The reason I chose ethernet was because my car wash's network is
ethernet based.

I have a system where the customer can get a code (from the gas pump at
the neighboring gas station) and enter that code to get a car wash. I
am wanting to put this into affect with the vacuums as well. This way
my customers can use the code to detail their entire car.

The vaccuum manufacturer's timer has the RS-232. The code system I
have has ethernet.

Also the vacs are about 150 ft from the service room where the central
system is located. I didnt want to run RS232 that far.

RS485 would be my choice but I want to use what my system already uses
for the self-serve bays and the automatic.

I know this may seem like a big project. If I cannot do it then I
cannot do it. I am at least wanting to attempt it and at worst all I
can do is learn some things on the way to my failure!!
I'd suggest you look for a cheap little embedded processor board with
Ethernet and serial ports on board, and program it up to do your
conversion. It's highly likely that you'll want to do some
interpretation and changes to the commands and data coming out of/in to
the different equipment so a small uP is the way to go. If this doesn't
meet your criteria to 'build it yourself' then you're probably aiming at
the wrong solution.

You might want to consider the use of 802.11 between the service room
and the vac equipment (with the serial <> IP converting uP located
there) to avoid cabling, or if you don't like radio (and who trusts RF
stuff anyway?? :) the use of fibre will go a long way to avoid
interference which may be an issue on a site like yours. A 150' link is
pretty inexpensive.

Cheers.

Ken
 
D

DaveM

Jan 1, 1970
0
The reason I chose ethernet was because my car wash's network is
ethernet based.

I have a system where the customer can get a code (from the gas pump at
the neighboring gas station) and enter that code to get a car wash. I
am wanting to put this into affect with the vacuums as well. This way
my customers can use the code to detail their entire car.

The vaccuum manufacturer's timer has the RS-232. The code system I
have has ethernet.

Also the vacs are about 150 ft from the service room where the central
system is located. I didnt want to run RS232 that far.

RS485 would be my choice but I want to use what my system already uses
for the self-serve bays and the automatic.

I know this may seem like a big project. If I cannot do it then I
cannot do it. I am at least wanting to attempt it and at worst all I
can do is learn some things on the way to my failure!!

If you're really set on ethernet for the connection and building from scratch, I
suggest a lengthy visit to Jan Axelson's site at http://www.lvr.com/index.html.
Jan has published a number of books related to your endeavor, dealing with
serial ports, parallel ports, imbedded ethernet, etc. All right up your alley.
I recommend that you spend a few evenings surfing the links on her site and
learning more about the technologies before starting earnestly on your project.
You'll definitely learn something and you might find a better way to get the job
done.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Never take a laxative and a sleeping pill at the same time!!
 
Thanks,

I actually bought her Serial Port Complete book just a couple weeks
ago. Havent started reading it yet though.

A uP is what I was looking at buying. If the code needs adjusted then
I have a programmer that can help me with that.

I dont know the ethernet protocol well enough to tackle this right now.
I am just wanting advice so I can get there eventually.

Thanks
 
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