Morning all
Sortation conveyor. 1756-L72 with a 1756-EN2TR as the ring supervisor, DLR ring through eleven 1783-ETAP taps and a few dual port 1734-AENTR racks. Studio 5000 V31.
Tuesday the whole ring went down, every rack 16#0204. Found a cable near the merge with the jacket rubbed through, replaced it, and half the ring came back. Then we found a second one under the cross belt, crimp corroded green, and that one was weeks old.
So we've been running on a broken ring for a good while and nobody knew. I checked the rest of the cables by hand and the ETAP at the merge looks fine to me. Is that ETAP going bad and eating cables, or is the beacon interval too slow to catch a break? And how do I get told the next time it's running on one path, rather than finding out weeks later with a torch?
The ring did exactly what it's for. First break, it heals, nothing stops. Second break, two islands. Nobody looked at the supervisor status for six weeks, that's the failure, not the ETAP.
OG
Fair. Not sure where I'd have looked though. Nothing on the HMI, nothing in the controller faults, no fault on the module in the tree. Only the Network tab and the EN2TR web page, and nobody opens those unless it's already down.
The supervisor tells you, you've got to ask it. Network tab has Ring Status and Last Active Node on Port 1 and Port 2, that's your fault location, but only if someone opens it.
To get it into the program, RA have a DLR ring status add-on instruction. It MSGs the DLR object on the EN2TR every couple of seconds and hands back Network Status as a DINT, 0 normal, 1 ring fault, plus the last active nodes either side of the break. Alarm anything that isn't 0 on the HMI and page maintenance. Leave the beacon interval alone. ENET-AP005 is the DLR application guide, the status object's in there. There's a writeup on the ring side here: https://plctr.com/advanced-plc-networking-and-communication-protocols/
Got the AOI in. The MSG inside it errors, 16#0005 path destination unknown. Message type CIP Generic, class 47, instance 1, attribute 2, path 1,2 for the EN2TR in slot 2. What have I got wrong there.
Class is hex 47. If the MSG dialog's showing decimal, type 71 or tick the hex box. Everybody gets the Identity object right because it's 1 either way.
Hex box ticked, MSG runs, and Network Status came back 0 with both cables fixed. Pulled one on purpose Friday with the line stopped, it went to 1 in about a second and the last active nodes showed the two taps either side of where I'd pulled it. The alarm's on the HMI now and it pages the shift lead.
So nobody was alarming the supervisor and the ring hid that first break for six weeks. The DLR AOI, MSG to class hex 47 on the EN2TR, alarm on anything that isn't 0, closed it out.
Still don't know how long that first cable had been gone, could be months, the crimp was green all the way through. Thanks rsdave, and billr for the kick.
Green all the way through, that crimp was gone long before Tuesday.
OG