Plant lost power Saturday night, came in for nights and the case packer remote rack is down. Main rack is a 1756 L83E with a 1756 EN2T in slot 2, remote rack is a 1734 AENTR.
The EN2T itself looks fine in the tree and everything under it has the yellow triangle. Connection tab on the AENTR says (16#0204) Connection Request Error: connection timed out. EN2T has OK solid green, and the little display on the front just scrolls BOOTP over and over. We power cycled the main rack twice and reseated the EN2T, same thing.
There's a spare EN2T on the shelf. Is it just dead? Asking first, because last time somebody swapped one it took half a day to get talking again. Any thoughts before I pull the trigger on a swap?
Don't swap it. Display scrolling BOOTP is the whole story, the module has no address. What are the three rotary switches on the front set to? Photo, they're small. And is anything on that network acting as a BOOTP server, or was there ever one?
OG
New here and I've got the same EN2T on our line. Not sure what BOOTP on the display actually means, is it waiting for something?
Switches are 999, photo attached. No BOOTP server that I know of, nobody has touched this rack since 2019. And no rookie_ray, I don't know either.
999 means take the address from a BOOTP or DHCP server. Whoever built it in 2019 gave it .20 with the BOOTP-DHCP tool and, if I remember right, that tool has a Disable BOOTP button at the bottom that people skip. The module keeps the address as long as it has power. Saturday cleared it. Now it asks and nobody answers, so no IP, so every child times out with 0204. The EN2T looks fine in the tree because the controller reaches it over the backplane, not over Ethernet.
Pat has it. Laptop on the same switch, open the BOOTP-DHCP EDS tool, the module's MAC shows in the request list within a minute. Add relation 192.168.1.20 with the mask, click the row in the relation list, then Disable BOOTP removed link That button stays greyed until a row is selected, catches people every time. Or skip the tool: switches to 020, power cycle, it comes up as .20 and never asks again. I'd do the switches. Writeup with the rest of the 16#02xx codes here: https://plctr.com/utilizing-ethernet-ip-in-plc-communication/
OG
Set the switches to 020 and cycled the rack on lunch break. EN2T came up scrolling 192.168.1.20, rack went green in a few seconds, packer running.
So BOOTP was never disabled back in 2019 and the outage wiped the address. Rotary switches sorted it, didn't even need the tool.
One thing I still don't get. That rack has been powered down for maintenance more than once since 2019 and it always came back. Either those weren't full power downs or the rack PSU is on a UPS nobody told me about. Going to find out.
Thanks billr and pat_k.
Switches at 999 on a six year old module. Marking solved.
plctr.com team