On the FlexMotion board, you use the Return Data Buffer to communicate with the host. The best solution for you will probably be to use the Return Data Buffer. When programming with FlexMotion, you can set the return vector on several of the VIs to send data back to the host. The data that is set to be sent to the host is sent to the Return Data Buffer or RDB. The host has access to the RDB and can read the data that comes in to it. You could set this up to act as a flag from your onboard program.
Regards,
Andy Bell
Application Engineer
National Instruments
