Hi newbie working with Arduino and VISA

Hi everyone, basically I have the arduino running ROS framework on it, and I need to set up a Labview interface to override the firmware. that part of the firmware code looks like this 

voidTdsae::ak(conststd_msgs::Float64ConstPtr&msg){std_msgs::UInt16driverMsg;driverPub.publish(driverMsg); 

and my labview code looks like this,   it seems the labview code failed to override, and I dont really understand why