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PLC Networking To Infilink

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  • PLC Networking To Infilink

    I have a lot of DL06 and P2000 PLC's on a factory network which are then accessed from the PC using Infilink software. This has been running for quite a few years with the 06 and recently the P2000's and some Weintek screens have been added. Today the Infilink software has lost connection with all the 06 plc's and some of the P2000's had to be rebooted so that they could be seen on the network. The screens have also complained about lost connections to the PLC's but I can still see data and turn things on and off. If I ping the PLC's it comes back with a response time <1ms. Running the netedit software and all the PLC's are there but occasional some will disappear when I refresh it. The PLC's are in different parts of the factory and are connected to different switches. Also we have tried different PC's located in different areas of the factory. KEPDirect is demoting the PLC's because they have lost connection yet at the same time I am pinging <1ms and this is on all versions of Windows. The IT department says that the network is running as normal and they are not having any issues. Does anyone know of any software which help prove that it must be a network problem or has Infilink and the PLC's just stopped working. There have been no updates or changes to any of the PLC's.

  • #2
    With a lot of devices on the network you could be getting too many packets and some are being dropped and then it shows lost connectivity when packets from some devices are supressed. Packets being dropped could be due to Denial of Service protections on the network seeing excessive traffic (which is how PLC traffic often looks) as an attack on the network and so the packets get dropped. Or it could be that the PLCs are generating too much traffic and the switches and PCs cannot process it fast enough so the network bogs down and buffers start being full and then packets get dropped when things fill up. This could be caused by the PLCs generating additional traffic lately, or a network segment dropping to a lower speed and not being able to support the traffic any longer.

    My guess would be that the issue could be one of three things:

    1) if you have gigabit connections between network segments, one or more of those may have dropped to 100mbit due to wiring issue or a port going bad.
    2) a change was made to one or more PLCs and they are sending out too much traffic now for the network to handle
    3) security services were updated and it sees your PLC traffic as malicious and is dropping too many packets and causing connection loss

    Run a ping test on a loop to a couple PLCs, do about 100 loops. They should all return under a couple milliseconds. If you see a few jumps up to dozens or even hundreds of ms then you have something most likely causing a lot of traffic on the network and is slowing your ping requests down. Slow ping requests mean your other network traffic will also be slow from too much traffic.
    If one or more ping tests return an error message about not reaching the device, then you have packet loss and that is a serious problem. That could be a network hardware issue or an issue with too much traffic causing dropped packets
    If every single one of the 100 loops to the PLCs you test returns each ping under a couple ms then my guess would be the problem is somehow in the PLCs. I find it unlikely that so many PLCs would have the same problems at the same time though.


    • #3
      Can a faulty PLC interfere with the other PLC's. I found one room which I could isolate from the rest of the factory and its 6 PLC's worked properly with the Inflink software I had on a laptop. When I plugged the room back into the network the Infilink lost the connection to the PLC's. Also it was only the DL06 ones that did not work. P2000's seemed to be OK. In other parts of the factory I have about 50 GS-EDRV100's on the network. Would any of these be able to disrupt the connection to the PLC's. An IT consultant was also in today and he could see nothing wrong the network and traffic flow.


      • #4
        Originally posted by robertkeenan View Post
        Can a faulty PLC interfere with the other PLC's.
        Duplicate IP Addresses definitely will mess up a network! This includes ANY device. PCs OR PLCs or printers or EtherNet/IP devices or ...

        If you are using DHCP, make sure you are not hard coding any fixed IP Address values that fall within the DHCP range!!

        There are 10 kinds of people in this world, those who know binary, and those who do not.


        • #5
          Or a possibility, if someone has looped a cable back into a switch, that will definitely make the network extremely unhappy. Either a single wire looped back or someone put two cables from one switch to another. Loopbacks on a switch are bad juju.
          If you have an urgent issue, please contact AutomationDirect's Technical Support team.

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