Strange Faulting of AB PF700 Drive

I have a really weird problem with an AB PF700 drive that only faults out with one specific product. Why it is weird is because it is a Port5 DPI Fault (F85). I know the solution is to replace the faulty component, up to and including the whole drive, which I will do at some point.

I just wanted your opinion on what my theory of why it is doing it is. This drive runs a section of many inline lugged conveyors. Every product has a different run speed, and this product is the fastest of them. My theory is that at the speed of this product there is a harmonic frequency within the drive that is causing some noise. This fault never occurs with any of the other products, so I figure it must be frequency related. This product is also the lightest, and actually draws less current than the others. So I ruled out problems do to high current draw.

What do you all think? Have any of you had this problem before also?

DPI Port 5 is your comm board.

Yeah, its a 20-COMM-E. The manual says:

1. If adapter was not intentionally
disconnected, check wiring to the
port. Replace wiring, port
expander, adapters, Main Control
Board or complete drive as
required.

Which I will do when I am able, I just find it weird to be doing it at only the one speed.

Not much in the tech. notes. Something about proper ground of the board. What firmware is the comm-e? Not that any of this explains why it only occurs at a certain speed.

FW REV. 8.2

Yeah, you would think that if it was grounding or firmware related the speed would not matter.

My thinking is that a component has a slight defect that leaks noise through to the Scanport part of the control board at certain frequencies. Maybe an inductor/capacitor coupling of some sort.

Increased speed = increased current = increased common mode noise, EMI/RFI even incuced voltages. A bad shield connection or a part of the Ethernet cables being non-industrial (i.e. bought at Office Depot) might not pick up enough to cause troubles at lower levels but do when it's higher. Also look for field made Ethernet terminations, one small mistake might be marginally acceptable under more ideal conditions but when the problems increase, the filter circuit on the 20-COM-E board gets overwhelmed.

As stupid as this is, I had a similar problem with a 20-Comm-D device net card on one of those drives. It was just the ribbon cable the Comm card is connected with, at certain speeds the vibration would be right to make her loose connection. Might check that if you haven't already.