Udp and multicast

2020-02-27T14:28:04.126000Z

Dear Edwin, can you help with simple example UDP Multicast? (Sender/Receiver)

Another topic with similar situation:
https://forum-de.codesys.com/viewtopic. ... 324#p17085

It would be nice to get simple example (for example, for Raspberry Pi) to undestand how it works in CDS V3.

Udp and multicast

2020-02-27T14:28:03.649000Z

The question is now:
how can i read the UDP multicast/broadcast data sent from other devices ?

Is it possible in codesysV3 ?

Udp and multicast

2020-02-27T14:28:02.371000Z

OK I've fixex the data transmission. You Don't need to separate IPaddr. and IPport of Peer and Sender. You only need to setup in the right way the Gateway of the device.

Udp and multicast

2020-02-27T14:28:01.873000Z

I solved (partially?) the issue by differentiating the ip address and port of Peer and sender.

PeerIpAddr.sAddr   := '255.255.255.255'; (* or 127.0.0.1 or other non multicast IP address *)
PeerIpPort         := 49999; (* or other port not used *)
SenderIpAddr.sAddr := '239.2.3.4';
SenderIpPort      := 2053;
RTR:   R_Trig;
Send:    BOOL;
DataTx:   STRING:='Hello Multicast !!';
--------------------------------------------------------------------------
UdpPeer(xEnable := TRUE, ipAddr := PeerIpAddr, uiPort := PeerIpPort);
IF UdpPeer.xError THEN
   UdpPeer(xEnable := FALSE);
   Send         := FALSE;
END_IF
RTR_Send(CLK:=OneShotCmd); (* check rise of send command *)
IF RTR_Send.Q AND UdpPeer.xActive AND NOT UdpPeer.xError THEN
   Send   := TRUE;
END_IF
   
(* UPD sender *)
UdpSend(
   xExecute   := Send, 
   ipAddr   := SenderIpAddr,
   uiPort   := SenderIpPort,
   hPeer   := UdpPeer.hPeer,
   szSize   := SIZEOF(DataTx),
   pData   := ADR(DataTx),
   udiTimeOut   := 1000000, (* usec *)
);
   
IF UdpSend.xDone THEN
   Send   := FALSE;   
END_IF
IF UdpSend.xError THEN
   Send   := FALSE;
   UdpSend(xExecute:=FALSE);   
END_IF

Problem: it is the right way ? Is there any guidelines for using these libraries ?

Udp and multicast

2020-02-27T14:28:01.362000Z

Hi all,
I'm trying to send data by UDP sockets but I get always error with multicast IP addresses (i.e. 239.2.3.4).
I'm able to send data to a "normal" IP address like 192.168.10.25 but not multicast or broadcast. I don't know what I wrong. I am new in Codesys v3.

declarations:

IP_Addr:   NBS.IP_ADDR := (sAddr := '192.168.10.25');
IP_Multicast:   NBS.IP_ADDR := (sAddr := '239.2.3.4');
IP_Port:      UINT := 2053; 
UdpPeer:      nbs.UDP_Peer;
UdpSend:      nbs.UDP_Send;

by using;

UdpPeer(
   xEnable   := TRUE,
   ipAddr   := IP_Multicast,
   uiPort   := IP_Port   );

UdpPeer returns "NO_ERROR" but UdpSend returns "UDP_SEND_ERROR"

Instead, by using:

UdpPeer(
   xEnable   := TRUE,
   (*ipAddr   := IP_Addr,*)
        ipMultiCast   := IP_Multicast,
   uiPort   := IP_Port   );

UdpPeer status returns "WRONG_PARAMETER" .
Same results by setting or ipAddr = '255.255.255.255' or '0.0.0.0' (see library doc)

Has someone an idea ?
Many thanks in advance

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