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Communication Errors

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  • Communication Errors

    DO-More Designer 2.2 and running H2-DM1E

    Why am I getting errors ST145 and ST146 errors occasionally and what can i do to stop it?
    The Help just tells you what it is and I can't find anything on how to fix it.

  • #2
    It means the internal packet queues are full (perhaps there is excessive traffic on your network) and the PLC is forced to clean up to keep up. It could be that it is coming in short burst from a packet happy device. We had a switch that would start spamming the network with dozens of unsolicited ARPs with near zero delay. It can also happen if you have created a TCP or UDP device, but aren't servicing a UDP Client that is receiving packets, but they aren't ever being removed.

    Take a look at $EthDroppedPkts(DST40) and $EthStoppedIntr(DST41). The first is the result of too many packets coming in single scan and the PLC starts dropping packets to slow the flow. The second is when it hits a higher limit in the scan and the PLC shuts the Ethernet interrupt off to protect itself.

    A PLC's first and most important job is to solve logic. These features are to make sure it does that, even when there is a data storm or some form of network attack like a DoS.


    • #3
      Problem solved rs232 rs485 serial comm issues solved ChirpX2 patented already in use by oil and gas co.