ros-industrial/ros_canopen

CAN Bridge Node can't differentiate between multiple interfaces after reception / before sending

njoye opened this issue · 3 comments

njoye commented

Currently the socketcan_bridge_node (consisting of the topic_to_socketcan_node and the socketcan_to_topic_node) can't differentiate between multiple socketcan interfaces as soon as the messages are published in the ROS network or before the messages are passed to the socketcan bridge. The reason for this is that the topic name of each node is fixed to received_messages and sent_messages without regard for the can interface. I will provide a PR in the next days that will make the topic name changeable through the use of ros parameters similar to the parameters that can be set for the can interface name. This will allow users to send data onto two different can busses without sending them onto both at the same time as well as receiving messages from different can busses on different topics which might reduce or eliminate the need for filtering and discarding unnecessarily received messages.

Backwards-compatibility will be achieved by defaulting to the existing topic names should no parameter be set.

gavanderhoorn commented

What about remapping the topics?

Topic names as parameters is a bit of an anti-pattern.

  • 👍1
ivan140 commented 
  <!-- Socket CAN bridge can1-->  
  <node pkg="socketcan_bridge" type="socketcan_bridge_node" name="socketcan1_node" output="screen">
    <param name="can_device" value="can1" />
    <!-- <rosparam param="can_ids"> [ ] </rosparam> -->
  </node>

  <!-- Socket CAN bridge can0--> 
  <node ns="can0" pkg="socketcan_bridge" type="socketcan_bridge_node" name="socketcan0_node" output="screen">
    <param name="can_device" value="can0" />
    <rosparam param="can_ids"> [ 390, 646 ] </rosparam>
  </node>

We're using 2 different can interfaces also by just putting the nodes into a namespace. :-)

njoye commented