Aoto10

Any way to have unlimited IP access using UDP to PLC using QJ71E71-100?

6 posts in this topic

I have a centralized PLC that acts as interface between all PCs in our building to all machines in the building. The building internet is connected to the PLC CPU ethernet port. I want to be able to send McProtocol messages to any PLC in the building using CC-Link IE.

I have made a program in C# that communicates to the centralized PLC with McProtocol using UDP on PLC port 4998. My C# program can run on any PC in our building and can read and write data to and from the centralized PLC. 

PLC2.png.7d5b31bb963c799b469826276da1557

The manual SH(NA)-080811 states computers can only communicate with the connected CPU module using McProtocol. As shown here

PLC1.png.abc98e42de0bc91ef1d1243d26bfdb0

So, to get around this I can use a QJ71E71-100 and I have been successful sending McProtocol messages to remote PLCs over CC-Link IE.

My issue is that the settings for QJ71E71-100 requires a set IP address to communicate per one connection. Example:

PLC3.png.b87216dd26527e018e9e9e313e7e66c

This ruins my original program design because in C# I would send a MC message to the CPU on port 4998 and it would work from any PC. I would like to have this same functionality on the QJ71E71-100. The only way I know of around this is to have all PCs send their request to a server and have a C# program running on the server handle all MC data.

 

So simply is there a way on the QJ71E71-100 to allow McProtocol messages to be processed on a port from any IP address like I can on the CPU ethernet?

 

CPU model is Q26UDVCPU. All other PLCs are communicated through CC-Link IE Field on QJ71GF11-T2 cards.

 

 

Edited by Aoto10

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CC-Link IE and MC Protocol, are not the same protocols.

You can add another MC Protocol connection, on the PLC CPU, using UDP, but with different port.

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11 hours ago, Goran Vuckovic said:

CC-Link IE and MC Protocol, are not the same protocols.

You can add another MC Protocol connection, on the PLC CPU, using UDP, but with different port.

Thank you for your reply.

I am aware they are not the same. My function is very basic in operation only using the read and write commands. It may be more accurate to say I'm using SLMP messages over CC-Link IE networks.

Like I mentioned I can't use SLMP with the CPU port to access other networked PLCs. But using the QJ71E71-100 I can access any networked PLC but I can't use any IP address on the same UDP port like I can with the CPU port. 

It may not be possible but maybe I missed something.

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You can change  QJ71E71-100 buffer memory from program and by doing that, you can change Destination IP Address.

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Using UDP On the Fx3U's for comms from the PC to the PLC we don’t specify the actual destination address but use 255,255,255,255 instead. Might be worth a try.

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UPDATE: I ended up just using TCP but the open and closing connections was slowing down my C# performance. If it helps anyone in the future, I found out you can send UDP messages to the E71 on port 5000 without using any open settings. This is an Auto-Open UDP port that never changes. This solves my original issue in the first post. 

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