H0-ECOM Sending Out Too Many Braodcasts

[tim s]

I have an H0-ECOM ethernet card installed on a DL06 PLC. My IT department is complaining because it is sending out too many broadcasts over the network. The IT person showed me a screenshot of Wireshark and sure enough it is the device in question. In 15 minutes it broadcasted 5 million packets. He also said maybe the ethernet card is going bad. My question is, is this the normal operation for this card? BTW, it does have the latest firmware version installed.

[franji1]

You said ECOM (not ECOM100).  Are you doing any RX/WX instructions on the ECOM slot?  I believe it will send out broadcast packets for those.

[tim s]

There are no RX/WX commands being executed by the PLC.

[franji1]

If you could send some of your wire shark traces to support@hosteng.com (maybe even just the screen shot you mentioned earlier), that would probably give us good info.

[tim s]

Message has been sent. Thank you.

[PLCGuy]

I would be interested in the results. And by the way, this is a good reason to have your own Machine Network. At our work, I am assigned couple hundred ip address on a separate machine network. We too had too much traffic on the network, and also, IT worried if there is a major crash of some sort, it will take down the whole network, so now we are separate.

[tim s]

That's a good point. I did recommend that about a year ago. It even says in some PLC docs to NOT connect to a business network.

[franji1]

tim s,

Got your email and responded.  Please post here if you did not get my email.

[franji1]

After talking with "Greg", it would appear that the PLC had ladder logic to send Report By Exception (RBE) packets, which are NOT broadcasts, but (are most likely) "normal addressed" IP packets.  But, if the ECOM module did NOT have Dip Switch 7 ON, the RBE mechanism would NOT be utilized, but instead would do the normal "directed broadcast" of a HAP protocol (DL ECOM) packet.  (RBE is designated in ladder program by using Address 90 in the RX instruction, and your V memory contains the IP packet address data in addition to any application data; the packets we saw were HAP protocol address 90, which is NOT a typical address, the address is usually 2, 3, 4, 5, 12, etc.).

If you just turn on Dipswitch 7 and keep your RX rung(s), I bet the broadcasts would go away.  Not only that, whatever server/database was getting those RBE IP data packets would start getting its data again.

I am not 100% sure this is the issue, but +90% sure.