Ewon Technical Forum

Hello,

I use Ewon Flexy 205 as a switch for profinet comunication between PLC simatic s1200, profinet device siemens ET200SP a siemens card SM1281 (not normaly profinet device). I have a problem, when plc send indetification profinet DCP packet for ET200. Normal lenght of this packet from plc is 56 bytes. But ewon adds four zeros to the end of this packet. So packet is then 60 bytes lenght. ET200 respons correctly always (if use normal switch or ewon). But SM1281 not. If I use normal switch SM1281 does not respons, because, it is request for ET200. But I use ewon (add 4 zeros), SM1281 respons to the request for ET200. So PLC has a problem because, it has 2 respons for one request. My question is why ewon add 4 zeros to the end of the packet profinet DCP? Can I switch off?

Thank you

Hello,

This sounds weird.
Do you mean that the Ewon is acting as a simple switch when you got the problem ?
Are you talking about the Profinet Explorer feature ?

Can you describe the setup/network when you have the problem ?

Simon

(01-12-2021, 08:09 PM)Hello,Yes, I mean the ewon as a simple switch. No profinet explorer feature. I have conneted to the switch plc s1200 and profinet devices (ET200, UPS, SM1281,...). I catch network traffic on the plc side and then i catch tarffic on the profinet device side with wireshark. The plc sends packet 56bytes PROFINET DCP for identification device. But on the device side comes 60bytes (the same 56bytes plus 4 times zero). If i use a normal switch, there is not this problem. Always is 56 bytes. Same devices as ET200, UPS has no problem with this situation, but the card SM1281 has a problem with this adding zeros.matejsimon Wrote: [ -> ]Hello,

This sounds weird.
Do you mean that the Ewon is acting as a simple switch when you got the problem ?
Are you talking about the Profinet Explorer feature ?

Can you describe the setup/network when you have the problem ?

Simon

Hi,

Sorry for the late reply,

Could you provide us the Wireshark traces you did ?
Honestly, I do not see how the Ewon could change the packets when it is simply acting as a switch.... ;-)
The packet does not even go on the firmware layer.

Hi,I attached wireshark's files. (in zip). The file profinet_ident.pcapng is on the side of the plc. Please use filter "pn_dcp". You can see, that the plc send the packet with 56 bytes length. The second file profinat_ident_sm1281.pcapng is on the side of device behind the ewon "switch". (use the same filter) You can see, that the same packet is not 56, but 60 bytes length. Ewon adds four zero bytes. A switch is not a switch ;-)m.[attachment=1278 Wrote:simon pid='6644' dateline='1640037665']Hi,

Sorry for the late reply,

Could you provide us the Wireshark traces you did ?
Honestly, I do not see how the Ewon could change the packets when it is simply acting as a switch.... ;-)
The packet does not even go on the firmware layer.

matej79

simon

matej79

simon

matej79