crio ethercat motion error

[brians08]

I have a cRIO-9074 connected to and AKD drive via EtherCAT, running in standard scan mode.

Simple straight line move using a softmotion express VI.

This is working fine except when I force the motor to stall, a strange thing happens.

When I hold the motor still it will suddenly reverse direction spinning at a faster reverse velocity than the requested forward velocity.  

The ADK faults out but it takes 100-400 ms to cut power.

The AKD displays F 503 and Labview shows an error code 6A3130.  This translated to "AKD phase failure".

Relavent part of this error is: " the single-phase connection has excessive power load" 

Obviously I am inducing a power over load so expect this fault but the reverse spin before the AKD cuts power is strange.

I have tried to duplicate this using the Kollmorgen Workbench software but so far it only happens when Labview is controlling via EtherCAT.

[CertifiNATEtion · Accepted solution]

Hi Brians, 

Taking the motor beyond normal operating limits may result in unexpected behavior. It is never recommended to intentionally stall the motor. In this case it sounds like LabVIEW is trying to remove stress inherent in the system in the case of a stall by reversing the motor. The reason you don't see this behavior in Workbench is because it does not contain the control algorithms that are present in LabVIEW. Additionally, I am curious on how you are determining the time the motor is turning in reverse; 100-400 ms seems very specific. If stalling the motor is a possibility in your code, I would program in a safety to handle that situation and perform whatever steps your application requires in the case of a stall. 

-N