Powerflex 525 loses AtReference

I have a powerflex 525 drive that will turn an auger forward and reverse. When production is idle the auger is programmed to keep running. We are using ethernet communication and a ControlLogix processor.
When the drive is running with the production line stopped after a while I loose the AtReference input from the drive to the PLC. Any ideas where to track this down?

What speed is the auger running at? Could it be binding?
Have you checked to see at the drive that it is actually running at the commanded speed?

running 60 hertz it is not binding up. While waiting for process the auger is running and I loose the AtSpeed reverence input to the PLC then I loose the Run Command output in the PLC.

The VFD is Ethernet and the (ED_CY01_10:I.AtReference) The VFD is a datatype for this tag. I loose that input so I do not know if this would be an Ethernet drop causing me to loose the input.

It won't be your ethernet dropping out that causes it. If you lose your ethernet connection to a drive, all the input data stays in the last known state. The drive is turning off it's AtReference tag deliberately.


Typically, I don't use the At Speed feedback unless it's really, really needed. If I need to wait for the drive to get up to speed before doing something else, I generally program it like this:
That way, motor 2 doesn't start until motor 1 is at speed. But after that point, it will continue to run just as long as motor 1 keeps running.


Otherwise, if you change the speed setpoint on Motor 1 and it has to ramp up or down, motor 2 will stop and restart, which is usually undesirable.


The same thing will happen if your drive for whatever reason deems itself no longer "at speed" for a short time. The code above gets around that.

Found that the Ethernet port on the Drive itself is bad. After swapping out the drive we have not seen anymore issues.