got 0 when I try to get the opticflow with px4flow_node

[Alexis-Martin]

when i try to get the optiflow with the px4flow_node package I always get 0 when my robot moves forward and a value close to 0 when it stops.
But when I read px4flow with QGroundControl the result is correct. So, i think that the problem isn't my sensor

My set up is:

• I plug my px4flow via the USB connector
• My px4flow is at 0.42m from the ground
• I try on a really contrasted ground (black and white stripe)
• I try with different speeds and different parameters (modified through QGroundControl interface)
• I'm on ROS Kinetic and ubuntu 16.04