title: How do I set up Python canopen with the usb2can interface?
body: <p>I am trying to use the Python <code>canopen</code> library and the <code>USB2CAN</code> adapter to communicate with a <code>canopen</code> 402 device. </p>
  
  <p>So far I have not been able to get past the most basic example of defining the network. </p>
  
  <p>The script crashes consistently on the error: </p>
  
  <blockquote>
    <p>"AttributeError: 'Usb2canBus' object has no attribute '_filters' " </p>
  </blockquote>
  
  <p>The documentation for python-can mentions that filters are not implemented for the <code>usb2can</code> device, but seems to imply that it should still be usable. </p>
  
  <p>Has anyone been successful in using the usb2can adapter with Python? </p>
  
  <p>I have not been able to find any examples, can someone point me to one?</p>
  
  <p>Below is one of the very basic examples included in the python canopen docs. </p>
  
  <p>This fails with the filters error described above, as do most other operations that I have tried.</p>
  
  <pre><code>import canopen
  import time
  
  #define network
  network = canopen.Network()
  
  #establish connection
  network.connect(channel='ED000200', bustype='usb2can', bitrate=500000)
  
  # This will attempt to read an SDO from nodes 1 - 127
  network.scanner.search()
  # We may need to wait a short while here to allow all nodes to respond
  time.sleep(0.05)
  for node_id in network.scanner.nodes:
      print("Found node %d!" % node_id)
  
  #close connection
  network.disconnect()
  </code></pre>
  
  <p>For this example I expect a list of nodes on the network to be printed, possibly an empty list because no nodes have been added. </p>
  
  <p>Instead I am getting the error: </p>
  
  <blockquote>
    <p>AttributeError: 'Usb2canBus' object has no attribute '_filters'</p>
  </blockquote>