title: Read/write values using Ethernet/IP
body: <p>I recently have acquired an ACS Linear Actuator (Tolomatic Stepper) that I am attempting to send data to from a Python application.  The device itself communicates using Ethernet/IP protocol.</p>
  
  <p>I have installed the library cpppo via pip.  When I issue a command
  in an attempt to read status of the device, I get None back.  Examining the 
  communication with Wireshark, I see that it appears like it is
  proceeding correctly however I notice a response from the device indicating:
  Service not supported.</p>
  
  <p>Example of the code I am using to test reading an "Input Assembly":</p>
  
  <pre><code>from cpppo.server.enip import client
  
  HOST = "192.168.1.100"
  TAGS = ["@4/100/3"]
  
  with client.connector(host=HOST) as conn:
      for index, descr, op, reply, status, value in conn.synchronous(
              operations=client.parse_operations(TAGS)):
          print(": %20s: %s" % (descr, value))
  </code></pre>
  
  <p>I am expecting to get a "input assembly" read but it does not appear to be
  working that way.  I imagine that I am missing something as this is the first
  time I have attempted Ethernet/IP communication. </p>
  
  <p>I am not sure how to proceed or what I am missing about Ethernet/IP that may make this work correctly.</p>