rostopic echo gets no data but node does

asked 2016-08-24 03:50:21 -0500

toblech gravatar image

This is how my setup looks like

  • desktop computer
  • odroid xu4 (arm computer)

I tried running the master on both computers and I export the the ROS_IP and ROS_MASTER_URI like that:

  • oroid: export ROS_IP=odroid_IP and export ROS_MASTER_URI=http://desktop_IP:11311
  • desktop: export ROS_IP=desktop_IP and export ROS_MASTER_URI=http://desktop_IP:11311

I publish image data from the odroid and I get the data on the desktop. I process the image data on the desktop computer and publish a std_msg::Float32 (lets call the topic "duration") message with a time stamp. So good so far...

Now here's the problem:

When I try plotting the "duration" topic with rqt or try rostopic echo "duration", I don't get any data. But when I write a small python script and subscribe to the topic "duration" and print the data on the console, it works just fine...

It also works if I run everything on the desktop computer (camera attached to the desktop) and run rqt or rostopic echo.

Any help would be appreciated


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To get it out of the way: you start rostopic in an environment where ROS_IP and ROS_MASTER_URI are correctly set? Just asking because I've seen ppl set it in one terminal, then open a new one and be surprised that things "don't work" in that one.

gvdhoorn gravatar image gvdhoorn  ( 2016-08-24 07:31:23 -0500 )edit

yes. Either I have it in my .bashrc or I source it every time I open a new terminal.

toblech gravatar image toblech  ( 2016-08-24 07:53:34 -0500 )edit