Neal Wareing
Field service technician and founder, FindFST
Looks fine. No comms.
Profinet plug was in the right port, nothing obviously wrong. But the machine wasn't talking.
Then look closer and you can see the profinet plug isn't properly closed.
The fix isn't pretty. Pipe grips, steady pressure, make sure every pin is actually biting into the conductor. Caveman engineering. But it works.
The temptation is always to replace the cable and move on. Takes longer, costs more, and half the time the new one has the same problem if you don't know what you're looking for.
A proper crimp tool and a decent RJ45 plug would have avoided all of it.
