Connect 2 controllers with EtherNet/IP through a router

exopphase

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Join Date
Aug 2020
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Indonesia
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Dear All,

I'd like to ask whether it is possible to connect 2 PLCs (both have EtherNet/IP capability) through a router.

Here is the case :
- We have 3 machines with each with Compact Logix AB PLC.
- We need to retrieve data from each Compact Logix AB PLC, to an Omron NX PLC via EtherNet/IP Protocol
- The problem is, currently each of the Compact Logix PLC has same IP addresses, since they are OEM machines installed with no integration in mind before.
- The OEM & Customer doesn't allow us to change the IP address of those Compact Logix PLC.
- The solution we could think of is to do NAT with router, the thing is we are not really sure whether EtherNet/IP could be translated by NAT.

Thank you :)
 
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Welcome to the PLCTalk forum community !

Make sure that the connection method uses Unicast and not Multicast, and it should work through a NAT device.

Do you plan to use one of the A-B branded NAT routers, or a NAT feature in a piece of networking gear you selected separately ?
 
Sure, just use the router as the gateway on the PLC.

Hi TheWaterboy, thanks for the insight. We'll note that down and will try it :) Have a nice day


Welcome to the PLCTalk forum community !

Make sure that the connection method uses Unicast and not Multicast, and it should work through a NAT device.

Do you plan to use one of the A-B branded NAT routers, or a NAT feature in a piece of networking gear you selected separately ?

Hi Ken, thank you for the welcoming reply. We plan to use a normal off the shelf router, not the ones from AB. Will it work then?
 
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Well it should, however the word "router" can be confusing. Your home internet is usually connect to a router but that may or may not work depending on the operating system.

What specific model do you have in mind?
 
Are there planned to be any other devices behind each of the routers, or is it one router per CompactLogix?


With a residential router, the latter case would be the simpler one; all that should be required is to forward ports 44818/TCP and 2222/UDP of each Compact Logix PLC to the WAN- (Omron-)side of its router, use a fixed IP address on the WAN side of each router, and point the Omron at each of the routers.


I'm doubt you want to use residential routers long-term, but it would be a cheap path to a proof of concept. From what I have seen elsewhere in this forum, there is an A-B routing device called a Stratix (Statix?) that does this with aplomb, but as they say, you may find a better way than A-B to do it, but not a more expensive way.
 
Are there planned to be any other devices behind each of the routers, or is it one router per CompactLogix?


With a residential router, the latter case would be the simpler one; all that should be required is to forward ports 44818/TCP and 2222/UDP of each Compact Logix PLC to the WAN- (Omron-)side of its router, use a fixed IP address on the WAN side of each router, and point the Omron at each of the routers.


I'm doubt you want to use residential routers long-term, but it would be a cheap path to a proof of concept. From what I have seen elsewhere in this forum, there is an A-B routing device called a Stratix (Statix?) that does this with aplomb, but as they say, you may find a better way than A-B to do it, but not a more expensive way.

Stratix devices are just rebranded Cisco IE series with a few added AB options. The run Cisco IOS and are literally physically and logically the same.

Also I may add, I love them. The web page is atrocious and slow, but using CLI through telnet or putty is so easy and powerful.
 
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Well it should, however the word "router" can be confusing. Your home internet is usually connect to a router but that may or may not work depending on the operating system.

What specific model do you have in mind?

Well to be honest not at the moment, still looking for one, my knowledge regarding networking device isn't that good. From a quick google search what I imagined would be a device like TP-LINK TL-R480T+, since I thought all so called "router" could do NAT.

Any additional insight to improve my knowledge would be very much appreciated


Are there planned to be any other devices behind each of the routers, or is it one router per CompactLogix?

Currently the configuration we're thinking of is just one router per CompactLogix

With a residential router, the latter case would be the simpler one;

I see...are you implying that should I opt, let say to have more than one CompactLogix (with the same IP addresses) per router, there is also a solution for that? Just out of curiosity though...

....all that should be required is to forward ports 44818/TCP and 2222/UDP of each Compact Logix PLC to the WAN- (Omron-)side of its router, use a fixed IP address on the WAN side of each router, and point the Omron at each of the routers.

I'm doubt you want to use residential routers long-term, but it would be a cheap path to a proof of concept. From what I have seen elsewhere in this forum, there is an A-B routing device called a Stratix (Statix?) that does this with aplomb, but as they say, you may find a better way than A-B to do it, but not a more expensive way.

Noted, we'll try it first and also have a look on Stratix.
 
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[...]

I see...are you implying that should I opt, let say to have more than one CompactLogix (with the same IP addresses) per router, there is also a solution for that? Just out of curiosity though...



Noted, we'll try it first and also have a look on Stratix.


Yes, maybe your IT department has a spare router you could set up to make things work with one of the CompactLogix. You would access the router web server from the LAN side to set up the port forwarding.


Btw, the need for port forwarding assumes the Omron is pulling data from the CompactLx's; if the CompactLx's are initiating the connections and pushing from the LAN side of the router to the Omron on the WAN side, the built-in NAT might do everything you need with no additional setup; it all depends on what happens with port 2222/UDP.
 
Btw, check this out:


https://teklager.se/en/best-free-linux-router-firewall-software-2019/


I had used DD-WRT in the past, but did not know was now out of favor; OpenWRT seems like a good alternative.



Although Endian is on the non-recommended list, for a simple application like the OP's where WiFi would be a distraction if not a security risk, it might work as well.


So if IT has an old unused router hanging around (and what IT department doesn't have several?), this could be used as a testbed.


Hmm, I wonder how hard it would be to get the OpenWRT project or one of the others to add the same features as a Stratix; maybe they already do.
 
Which is why I included putty in my original post, for serial or SSH.

I actually still use hyper terminal from time to time šŸ˜….




Oh I saw the mention of putty, it was just so jarring to see Telnet mentioned; I thought I was the last dinosaur (does [telnet horizons.jpl.nasa.gov 6775] still work?).
 

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