Main Site Documentation

Network RLP


#1

Hello,

I’m looking for een RLP which will send my data over the network connection. The RLP needs to take care of the connecting part and the sending part, because I just want a application which can send RAW data when it’s connected to a client.

Kind Regards


#2

RLP is not made for such use. Why do you need RLP to handle network?!


#3

I use an ChipworkX dev. System to process the realtime data and then send the data away over the UART-port. I have an other device(http://www.perle.com/products/IOLAN±Terminal-Server.shtml) which receives the UART data and then takes care of the client side for me!

Now I can connect to this Perle IOLan and receive raw packets with data. What I want is that I can connect with my client to the ChipworkX Dev. System and then just send away the realtime data without slowing the application. Can you help me find a solution?


#4

If you are doing all your application in RLP (C language) then why do you need Micro Framework (C# language)? I mean why not use any processor board out there, maybe running RTOS or Linux?

Also, network traffic is usually not real time even if your application is real time so I do not understand why you need a real time device on a network.


#5

Hi Gus, I do not require real time access to the Ethernet port (<100ms will work) but I need to implement an EtherCAT protocol driver at the “Layer 2” of the OSI model.


#6

[quote]EtherCAT UDP packages the EtherCAT proto-
Particularly useful for system wiring is the combination
of line and branches or stubs: the required interfaces
exist on many devices (e.g. on I/O modules); no additional
switches are required. Naturally, the classic switch-based
Ethernet star topology can also be used.
Wiring flexibility is further maximized through the
choice of different cables. Flexible and inexpensive standard
Ethernet cables transfer the signals in 100BASE-TX
mode. Plastic optical fibers (POF) will complement the system
for special applications. The complete choice of Ethernet
wiring – such as different optical fibers and copper cables
– can be used in combination with switches or media
converters.
The Fast Ethernet physics (100BASE-TX) enables a cable
length of 100 m between two devices. Since up to 65,535
devices can be connected, the size of the network is almost
unlimited.
The Ethernet protocol according to IEEE 802.3 remains
intact right up to the individual device; no sub-bus is required.
In order to meet the requirements of a modular device
like an electronic terminal block, the physical layer in
the coupling device can be converted from twisted pair or
optical fiber to LVDS (alternative Ethernet physical layer,
standardized in [4,5]). A modular device can thus be extended
very cost-efficiently. Subsequent conversion from
the backplane physical layer LVDS to the 100BASE-TX physical
layer is possible at any time – as usual with Ethernet.
■ Figure 4: EtherCAT: Standard Frames according to IEEE 802.3 [3]
munication between controllers (master/master). Freely
addressable network variables for process data and a variety
of services for parameterization, diagnosis, programming
and remote control cover a wide range of requirements.
The data interfaces for master/slave and master/
master communication are identical.
For slave-to-slave communication, two mechanisms
are available. Upstream devices can communicate to
downstream devices within the same cycle – and thus extremely
fast. Since this method is topology-dependent, it is
particularly suitable for slave-to-slave communication relationships
given by machine design – e.g. in printing or
packaging applications. For freely configurable slave-toslave
communication, the second mechanism applies: the
data is relayed by the master. Here, two cycles are needed,
but due to the extraordinary performance of EtherCAT this
is still faster than any other approach.
EtherCAT only uses standard frames according to [3] –
the frames are not shortened. EtherCAT frames can thus be
sent from any EthernetMAC, and standard tools (e.g. monitor)
can be used.
■ Topology
Line, tree or star: EtherCAT supports almost any topology
(see Fig. 5). The bus or line structure known from the fieldbuses
thus also becomes available for Ethernet, without
the quantity limitations implied by cascaded switches or
hubs.
col into UDP/IP datagrams (see Fig. 4). This enables any
control with Ethernet protocol stack to address EtherCAT
systems.[/quote]

Isn’t it only UDP?


#7

It is usually implemented at the lower level (below IP in the OSI model) but it may also be encapsulated (at the expense of determinism) in UDP or TCP if routing is required.