I'm having a problem that I suspect is mainly on the AB/Rockwell side, but while I'm waiting for a response from Rockwell tech support, I figured I'd double-check with the hive mind here.
My DeviceNet slave is an AB 1734-ADN Point I/O DeviceNet adapter with three I/O slices: two IB8s, and one OB8, in that order. My robot is an R-30iB running version 8.22.
If I power up the module without powering up the robot, the adapter shows a green light on the PointBus LED (indicating communications between the adapter and the slices is good). Each slice's Module Status light is green, but the Network Status lights on are dark, which the manual says means that the "MAC ID Dupe test" has not been carried out. That makes no sense, since the slices should be automatically picked up by the adapter, shouldn't they?
The weirdness happens when I boot the robot. Once the robot boots, it begins communicating with the adapter: the I/O DeviceNet screen shows the module online with no errors, and the DN light on the adapter turns solid green. But, when the DN connection is made, the PointBus light on the adapter changes from solid green to blinking red, and the Network Status lights on each I/O slice change to blinking green (the first slice) and blinking red (the next two slices).
I'm stumped. On most brands, I would expect that any errors on the "backplane" connection between the adapter and the slices would show up regardless of whether the DeviceNet was active or not. Obviously, with this AB hardware, that's not the case.
I' trying to figure out if this adapter requires some kind of setup using RSNetworx before it can be used as a simple "dumb" I/O adapter, or if I have something else going on. Right now, the DN config in the robot is set up for 2 bytes input, one byte output, which matches my hardware exactly, but I've heard that even the "dumb" AB adapters usually have extra status/control bytes that need to be accounted for in the Master-side DN configuration. But if that was the problem, shouldn't the robot be throwing DN config errors, due to the expected I/O size and the actual I/O size not matching? And I can't find anything in the AB manuals that would tell me how many "extra" bytes I might need to account for here.
I have checked my DN cable resistance with everything turned off, and confirmed that it's 60 ohms between CAN+ and CAN-. And the robot is sourcing 24VDC on the power pins, and the shield is connected properly at both ends. There are no extra branches, or any other devices, on this DN bus -- just the robot, and the ADN.