Old case line. SLC 5/04 with a 1747-SDN scanner, DeviceNet at 250 kbps, thick trunk. Somebody in 2015 extended the trunk out to the new stacker, so it is a long one now.

The nodes at the stacker end, three 1791D CompactBlock I/O and a PowerFlex 40 with the DeviceNet card, drop in and out. Scanner display cycles 78 and 72 for nodes 22, 24 and 25, then back to 80 when they come back. Near nodes never drop.

Tried: swapped node 24 for a spare, same. Trunk power is 24 V at the near end and reads 23.6 V at the far end. Terminators both ends, 121 ohm, checked with the meter with the power off.

Is the far end starved for power, or is one of those nodes dragging the others down? RSLogix 500 is v10, the scanner file is as old as the stacker.