Inconsistent MES-PLC connection

3 posts in this topic

In the MES log files it confirms my observations that we are losing communication from the PLC to the MES US module on a daily basis, even a few times daily. The Q03UDECPU communicates with the MES module through its CPU front port through a 116TX N-tron Ethernet switch. If anyone can help ensure consistent communication without dropping connection that would be appreciated. I'd also like to know if anyone would share PLC program ideas to make sure I have constant communication with the MES module. Should I just use a simple timer that waits for the MES module to toggle a bit, then fault out if the bit isn't toggled within a certain period of time? It feels too simple to be robust haha. Anyways, any ideas on this communication would be appreciated.   


I  should also note that I have an EIP4CCPU module in the same rack as the PLC that is connected to the same Ethernet switch looking at other Ethernet IP devices. I wouldn't think this would be causing traffic (due to fast RPI?) or issues in the Enet switch, but I figured it is worth mentioning in case anyone has any reason to believe this is an issue. 

Edited by Paolo_911

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Doesn't EthernetIP broadcast all messages? Or is that a different brand? I don't remember exactly but there is one provider who recommends physically (and I mean physically - NOT VLAN tagging) separating the networks due to broadcast messages...

Anyway: You say you loose connection between PLC and MES module, but the MES module is connected to the same rack as the PLC? Or are there two different racks?? If the same rack, you don't need to "communicate" between MES and PLC using Ethernet...

I'm not into the U.S. definitions of the MES module, does "MES US" mean the CCPU controller with DeviceWise software loaded, or is "MES US" the QJ71MES96 module?

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Maybe I'm not understanding your setup fully...

You have the  Q03UDECPU  and the MESIT module on the same rack but you're communicating over Ethernet instead of the back plane?

Also, according to Mitsubishi, the Ethernet port on any CPU is not intended for anything other than "Light" work.  If you are using the port for large data transfers/communication you might want to consider a dedicated Ethernet module.

I'm assuming that when you way that you're loosing the network that the MESIT module is faulting out?

If that is the case you may need to look into your scan times, and use some on demand triggers.

As for t/s networking connectivity, if you have a manageable switch (sorry, didn't look up your model) you can mirror the ports and put Wire shark on it.

Just some brainstorm ideas here, disregard if I didn't understand your questions fully.


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