case packer rack went down around 1am, 1756 en2t in slot 3, OK led solid red. grabbed the spare en2t out of the crib, switches on it were 999 same as the dead one, dropped it in. it came up, scrolled an address, then the NET led went solid red and stayed there.
about a minute later line 2 rang, their palletizer rack is down as well, same solid red NET led, and line 2 is on its own switch in its own panel. i tried a different port and reseated the spare twice, no change.
is the spare bad too? not sure what to make of line 2 going over at the same minute. we have one more spare but im not putting it in until someone tells me why, any help would be appreciated
Solid red NET on an EN2T is duplicate IP detected. The module shuts its own port. It doesn't need a switch to do that.
What address does the spare scroll on the display, and what does the line 2 module scroll?
OG
spare scrolls 192.168.10.41 then a line about duplicate and a mac, cant read it in time. line 2 guy says his palletizer en2t scrolls the same thing, 192.168.10.41 and duplicate. ours is supposed to be .23, thats what the dead one had.
so both of them think they are .41? line 2 has its own switch though.
Own switch isn't own network. If both panel switches uplink to the same core on one VLAN then it's one flat layer 2 domain, and a duplicate address is seen everywhere on it.
What happens is the spare comes up, sends an ARP probe for 192.168.10.41, the line 2 module answers, and both of them detect the conflict and shut their ports. That's the address conflict detection in the EN2T doing what it should. Wireshark on either panel would show the probe and the reply, one line each.
The spare's fine. I reckon it kept 192.168.10.41 from the line 2 palletizer, somebody pulled it on a repair and put it back in the crib without clearing it. 999 means the address lives in the module's memory, so it carried it along.
Pull the spare, on the bench give it 192.168.10.23 with the BOOTP-DHCP tool and disable BOOTP so it sticks. The rotaries are no use to you, they only do 192.168.1.x. Then it goes in the rack. Line 2's module needs a power cycle to open its port again. Label every spare with the last address it had. Address plan and the flat network thing, there's a writeup here: https://plctr.com/advanced-plc-networking-and-communication-protocols/
OG
pulled the spare, gave it 192.168.10.23 with the bootp tool on the bench and disabled bootp, put it back in. display scrolled 192.168.10.23, NET led green, rack came back. line 2 power cycled their en2t and theirs came back too.
so it was the spare still carrying 192.168.10.41 from line 2, and both lines sitting on one flat network. setting it on the bench before it goes anywhere near a rack, that was the whole job. we have a label on the second spare now and a sharpie on the crib shelf.
still dont get why line 2 didnt come back on its own once i pulled the spare, maybe it holds the port shut until you cycle it. thanks billr and petek
Marking solved. Label the spares.
plctr.com team