Ethernet UDP, is this also a industrial protocol

[arbj]

Hi,

I have seen some industrial devices that mention Ethernet UDP as a means of communication..

I know they use ethernet communication but is there a protocol called Ethernet UDP ??

I know UDP is a protocol of TCP/IP but is there a industrial protocol that uses just UDP ??

thanks
a

 

[robertkjonesjr]

There are several Industrial protocols that use UDP (there are others I am sure - this is my short list of ones I know about):

1. ModbusUDP - ModbusTCP is more common, but some run Modbus over UDP instead.
2. EtherNet/IP Class 1 messaging - still needs TCP to setup the CIP connections, but actual data transfer is through UDP. May be multicast as well.
3. Schneider Electric's Global Data - all UDP with data sent as multicast.
4. Codesys Network Variables - UDP based. If I recall could be unicast, multicast or broadcast.

 

[BryanG]

UDP isn't specific to Industry. TCP Transmission Control Protocol is a method of transmission that sends data, then waits for confirmation that the data has been received, before sending more data. Error correction is built in. UDP User Datagram Protocol doesn't wait for confirmation that data has been received before it sends the next lot of data. It doesn't have the built in error correction so you have to perform the error detection in the software. So TCP is used where data integrity is more important, UDP is used where speed of transmission is more important.

Typically UDP is used for streaming TV across the web because a little bit of screen corruption is less of a problem than would be a stuttering picture.http://en.wikipedia.org/wiki/Transmission_Control_Protocol

 

[The Plc Kid]

You will find that most Protocols use both UDP and TCP depending on the data being transmitted. I don't know of an industrial Ethernet based protocol that uses UDP only.

If you find one let me know.

 

[Mark-]

Hello,

>I don't know of an industrial Ethernet based protocol that uses UDP only.
>If you find one let me know.

Saia-Burgess Ether-S-Bus
Toshiba

I agree it is rare.

TCP/IP is connection based, UDP/IP is not. That makes a huge difference in resources for an operating system. For example, if I have very limited RAM, a slow clock speed, 8 bit only, etc., UDP is the way to go. An external device ask for data I respond. Using TCP I have to maintain a connection for each client, keep packet order, retries, etc., lots of overheard.

My2c.

 

[Tim Ganz]

Hello,

>I don't know of an industrial Ethernet based protocol that uses UDP only.
>If you find one let me know.

Saia-Burgess Ether-S-Bus
Toshiba

I agree it is rare.

TCP/IP is connection based, UDP/IP is not. That makes a huge difference in resources for an operating system. For example, if I have very limited RAM, a slow clock speed, 8 bit only, etc., UDP is the way to go. An external device ask for data I respond. Using TCP I have to maintain a connection for each client, keep packet order, retries, etc., lots of overheard.

My2c.

Says TCP here http://www.sbc-support.com/en/product-category/communication-protocols/

What about Profinet? What does it use? We just got a new machine with Siemens Profinet VFD.

 

[Mark-]

Hello,

Ether-S-Bus is UDP/IP only.

Where the web page says "Ether-S-Bus (TCP/IP)" that is not correct. The device does support some protocols using TCP/IP but, Ether-S-Bus is UDP/IP only.

http://wiki.wireshark.org/EtherSBus

http://www.sbc-support.ch/faq/item/item.framed.php?it=101079

I do not know what Profinet uses.

 

[RussB]

Says TCP here http://www.sbc-support.com/en/product-category/communication-protocols/

What about Profinet? What does it use? We just got a new machine with Siemens Profinet VFD.

Profinet attains its speed and predictability through UDP. The configuration and messaging uses TCP/IP but all of the important I/O data is via UDP. This is also their means of controlling the band width to maintain promised maximum through-put or I/O update times.

 

[mk42]

My understanding is that the realtime (and isochronous realtime) parts of the Profinet standard don't use TCP or UDP at all. For the cyclic realtime IO data, Profinet bypasses the overhead of the IP layer entirely, and communicates directly at the ethernet level using hardware MAC addresses. For alarms, diagnostics, configuration, and other non-cyclic traffic, it uses TCP/IP. This enables it to be high performance when needed, but still maintain compatibility with standard ethernet applications.

I attached the clearest picture I could find, from the link below.

http://support.automation.siemens.com/WW/view/en/51725188