https://forge.codesys.com/forge/talk/CODESYS-V2/thread/5ef5f83b6c/2020-02-27T19:33:29.504000ZRecent posts to Task can lockup if UDP Transmitter or Receiver is not there.2020-02-27T19:33:29.504000Z2020-02-27T19:33:29.504000Zjking22https://forge.codesys.com/u/jking22/https://forge.codesys.com9352fc89b1f705dae11d2aa0fc07b8b5685c9a1c

<div class="markdown_content"><p>We've experience that if you have a UDP nework (Ethernet or CAN) the following has the potential to lockup the task that uses the variables.</p> <ol> <li> <p>If the CAN network over which the UDP messages are sent is disconnected, the task that uses these variables can lockup.</p> </li> <li> <p>If at least 1 value isn't received for every receive UDP Ethenet variable then any task that uses this variable has a tendency to lockup. --&gt;We work around this by creating a unique task just for copying incoming UDP messages to another list of global variables that can be used by the original task. </p> </li> <li> <p>If you broadcast Ethernet UDP to a specific IP address and that IP isn't online the controller can lockup. --&gt; We work around this by doing a global broadcast (255.255.255.255 with unique ID) This gets broadcasted over every Ethernet port.</p> </li> </ol> <p>Yes we can work around these issues, however this doesn't seem to be as it should and the workarounds can be a little cumbersome. We do not have these issues with the CANopen stack. </p> <p>Is this:</p> <ol> <li> <p>A problem/limitation of the hardware?</p> </li> <li> <p>A bug within Codesys or at least the libraries I have.</p> </li> <li> <p>A case where I'm unaware of some bit I can set in a data structure that basically implies. Don't throw errors if I never receive any UDP message or the destination is not there. I'll take care of this on my own?</p> </li> <li> <p>A case where I need to keep resetting an Ethernet fault stack because the destination is not there?<span>[/img]</span></p> </li> </ol></div>