Subscriber node not working for topic at 50Hz

edit

Hello all,

So I have a topic published by a publisher node, at 50 Hz. The topic publishes a message 'loadMsg' which consists of the following data types

1) string unit

2) float64 load

Now I have my subscriber node, which is the following piece of code

#include <ros/ros.h>
#include <robot_comm/robot_comm.h>
#include "std_msgs/String.h"
#include "cell_node/loadMsg.h"


void loadSensor(const cell_node::loadMsg &d)
{
  ROS_INFO("Load Unit = [%s] , Value = [%lf] ", d.unit.c_str(),d.load);
}



int main(int argc, char** argv)
{
  ros::init(argc, argv, "demo");
  //FILE * pFile;

  ros::NodeHandle n;

  ros::Subscriber sub = n.subscribe("loadSensor", 1000, loadSensor);
  //ros::Rate loop_rate(50);
int i = 0;
while(i<10)
{
  usleep(20000);
  ros::spinOnce();
  i++;
}
  //pFile = fopen ( "myfile.txt" , "w+" );
  //fwrite (buffer , 1 , sizeof(buffer) , pFile );
  //fclose (pFile);

return 0;
}

So what this should do is basically sample from the stream of 'loadMsg' data being published at 50Hz. And the sampling should happen again at 50Hz (1/20000usec).

However, I am not getting any output! rosmake/make work perfectly, without any errors. When I run the node however, I get nothing.

What may be going wrong? In an earlier post, I asked a similar question. But it worked then, it refuses to work now. Here is the link to that:

http://answers.ros.org/question/38131/rosspinonce-not-functioning-properly/

Also, if I replace ros::spinOnce() by ros::spin() and remove the while loop, then it does sample from the topic, but seemingly at a lesser frequency.

All help is greatly appreciated!