When I was referring to a "Stop Move" I was referring to a SoftMotion move option. Just like a Straight-Line Move or Contour Move or Arc Move, the Stop Move can be created and have methods/properties called via invoke/property nodes.
https://forums.ni.com/t5/NI-Labs-Toolkits/LabVIEW-NI-SoftMotion-Module-2009-SP1-Property-Invoke-Nodes/ta-p/3494129?profile.language=en
""Create—Use the Create polymorphic VI to create a reference to specific NI SoftMotion interface objects. You can select from the following options:
Straight-Line Move
Arc Move
Contour Move
Find Reference Move
Position Capture
Position Compare
Stop Move
Gearing
Camming
Time Sampled Read - See Known Issues""
Creating a stop move, and then using the invoke node to start the stop move tells the motor to stop moving.
Sharing some of your code may help shed some light on what exactly you're doing, because there are a few different interfaces to SoftMotion, ie express vis, property nodes, or the subVIs they ship with.