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Ethernet?

  • Thread starter Marco Trapanese
  • Start date
M

Marco Trapanese

Jan 1, 1970
0
Hello,

a computer has to communicate with a remote unit. The length of the link
(optical fiber) is about 500 m. I need to transmit data in both
direction and a video stream from the remote unit to the PC.

This is my idea:

On the remote board I use a Rabbit Module or something else with
Ethernet capability. Thus, I may open a data stream on a port and a
video stream on another.

Some questions:

1) How to convert the video signal (from a camera) to a digital video
stream in order to send it over the Ethernet? I'm looking a stand-alone
solution, the Rabbit Module has to manage the whole board and it can't
spend time with the video.

2) What equipment do I need to create an Ethernet link between a PC and
the board on a fiber?

Do you have other ideas?
If you need further details to suggest me something, please feel free to
ask!

Thanks
Marco / iw2nzm
 
J

Jan Panteltje

Jan 1, 1970
0
Hello,

a computer has to communicate with a remote unit. The length of the link
(optical fiber) is about 500 m. I need to transmit data in both
direction and a video stream from the remote unit to the PC.

This is my idea:

On the remote board I use a Rabbit Module or something else with
Ethernet capability. Thus, I may open a data stream on a port and a
video stream on another.

Some questions:

1) How to convert the video signal (from a camera) to a digital video
stream in order to send it over the Ethernet? I'm looking a stand-alone
solution, the Rabbit Module has to manage the whole board and it can't
spend time with the video.

There are several cameras with Ethernet output, DCS-900 for example.

2) What equipment do I need to create an Ethernet link between a PC and
the board on a fiber?

Depends on what that board ahs as interface.

Do you have other ideas?

Oh yes!!!!

If you need further details to suggest me something, please feel free to
ask!

Specify more details.
 
M

Marco Trapanese

Jan 1, 1970
0
Jan said:
There are several cameras with Ethernet output, DCS-900 for example.

You're right, but the user might want to use a special camera for his
own purpose. In this case the video output must be encoded and
transmitted over the Ethernet.
Depends on what that board ahs as interface.

The board is not designed yet. So I can select what I need. As first
attempt I would use a Rabbit Core Module with Ethernet on-board. So I
have to interface the eth connector to the fiber.
Oh yes!!!!

Great :)
Specify more details.


What kind of details?

Some inputs:

+ the host sends to the remote board a string of about 50 bytes. This
contains commands or configuration data

+ the board receives the commands, decodes them and moves motors or
other actuators

+ into the remote unit there are several sensors and data acquired is
sent to the host. The video stream is also sent.


The PC has two monitors. One for the camera and the other to display
sensors data.

Bye
Marco / iw2nzm
 
J

Jan Panteltje

Jan 1, 1970
0
The board is not designed yet. So I can select what I need. As first
attempt I would use a Rabbit Core Module with Ethernet on-board. So I
have to interface the eth connector to the fiber.
Some inputs:

+ the host sends to the remote board a string of about 50 bytes. This
contains commands or configuration data

+ the board receives the commands, decodes them and moves motors or
other actuators

+ into the remote unit there are several sensors and data acquired is
sent to the host. The video stream is also sent.


The PC has two monitors. One for the camera and the other to display
sensors data.


mm, I cannot help you with the optical interface board.
But somehow you will have to specify what sort of cameras you want to
connect (support).
There are several types, from analog, to firewire, to USB, to ethernet,
to other digital standards.
To send info via ethernet you very likely need some sort of compression,
and if that is not in the camera, then 'the board' needs to have a powerful
enough processor to do that, faster then 500MHz I'd say.
This also depends on picture size and frames per second, quality etc..

Once it is TCP/IP, the control data can be send to one server
running on the PC, the camera stream to an other server.
So 'the board' needs much of the properties of a normal PC, and you
need programing experience to write the required soft, both for the PC,
and for 'the board'.

I have done this thing, except for the optical part, with cameras and camera control,
as I was free to choose my own format, and have no problem writing soft like
that, it was not much work.
Maybe you need to look for an embedded system for 'the board' that runs Linux,
as then you have compiler and library support....
I wonder if 'the board' can be a normal PC with a PCI card to interface to the
fiber?
That would give you firewire, USB, ethernet, etc interfaces and drivers for different
cameras.
Else drivers will be your biggest problem.
So more details on what type of cameras, what you can do on the software level,
The control part can be really simple I think, the smallest embedded system could do it.
No need to design these even, these are cheap, but I have not tried these:
http://www.calao-systems.com/index.php?lng=en
Design just a plugin for your fiber perhaps, use with an ethernet camera and switch,
and you are done, apart from the software.

Regards
Jan
 
M

Marco Trapanese

Jan 1, 1970
0
Jan said:
mm, I cannot help you with the optical interface board.
But somehow you will have to specify what sort of cameras you want to
connect (support).
There are several types, from analog, to firewire, to USB, to ethernet,
to other digital standards.
To send info via ethernet you very likely need some sort of compression,
and if that is not in the camera, then 'the board' needs to have a powerful
enough processor to do that, faster then 500MHz I'd say.
This also depends on picture size and frames per second, quality etc..

Maybe an embedded system could be an acceptable trade-off. I'm wondering
if there are any integrated modules to compress an input video signal
into an output digital stream in real-time (without use a PC).
Once it is TCP/IP, the control data can be send to one server
running on the PC, the camera stream to an other server.

Another server or another port of the same TCP (or UDP) connection, right?
So 'the board' needs much of the properties of a normal PC, and you
need programing experience to write the required soft, both for the PC,
and for 'the board'.

No problem, I wrote software for PC, for networks and for embedded systems.
Maybe you need to look for an embedded system for 'the board' that runs Linux,
as then you have compiler and library support....

It's a good solution, but I prefer to use a lower-level architecture.
I wonder if 'the board' can be a normal PC with a PCI card to interface to the
fiber?

No, it can't. It should be like a machine, rather than a PC. Safety is
very important so I'm trying to avoid operative systems.
So more details on what type of cameras, what you can do on the software level,
The control part can be really simple I think, the smallest embedded system could do it.
No need to design these even, these are cheap, but I have not tried these:
http://www.calao-systems.com/index.php?lng=en
Design just a plugin for your fiber perhaps, use with an ethernet camera and switch,
and you are done, apart from the software.


I thank you for your interesting information!

Marco / iw2nzm
 
G

Guy Macon

Jan 1, 1970
0
Marco said:
No, it can't. It should be like a machine, rather than a PC. Safety is
very important so I'm trying to avoid operative systems.

So you imagine that you can build a task schedular and resource
allocator by hand that is less likely to have bugs than a RTOS
with years of testing and use by a wide variety of users? Let
me know how that works out for you.
 
M

Marco Trapanese

Jan 1, 1970
0
Guy said:
So you imagine that you can build a task schedular and resource
allocator by hand that is less likely to have bugs than a RTOS
with years of testing and use by a wide variety of users? Let
me know how that works out for you.


mmm, maybe there was a misunderstanding. The firmware on the remote
board is simpler than you may expect. The current version of the project
uses a small PIC: it receives data, updates DACs, reads ADCs and
transmits back new data. It's straight and short. The next step is to
implement a PID controller (so the need of a fast processor) and
eventually manage the eth link (so the need of a module with eth on-board).

Bye
Marco / iw2nzm
 
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