Combining ModbusTCP with Ethernet/IP


Thread Starter



I’m currently investigating a new machine design for my company and I am having difficulties finding some information.

I’m aware of the different protocols available for Ethernet, and I know of basic network communications, hand shaking etc.

What I need to know is can you have 2 devices on an Ethernet network, 1 using ModbusTCP/IP, the other Ethernet/IP. I’m going to go with what I THINK and with what seems common sense and say that they are not compatible because of the handshaking and probably the packet construction used for each protocol.

But I may be unaware of a possibility to use the two together. I’m also thinking that would be a module in itself.


Michael King

You can connect all Ethernet devices on the same network (common switches, routers). But to communicate between devices is a bit problematic, because of different protocols, however all use the same network as a carrier only.

You need a kind of gateway between these devices. Ask your drive manufacturer the availability of Ethernet IP module, or better: Ask Rockwell to provide MB TCP/IP port.
If not, try to find gateway from

Good luck.
Hi Mike,

Since both "protocols" still have to use Ethernet packet rules I would think this would work. The actual information is "embedded", eg. Modbus TCP/IP or AB IP. Each target unit should simply only respond to the appropiate embedded information. Make sense??

James Ingraham

> can you have 2 devices on an Ethernet network, 1 using ModbusTCP/IP, the other Ethernet/IP. <

Yes, they can be attached to one network. No, they can't talk to each other.

> But I may be unaware of a possibility to use the two together. I’m also thinking that would be a module in itself. <

Yes. There are several different Modbus-TCP to Ethernet/IP gateways. Prolinx Gateways, HMS (AnyBus), and Woodhead / Applicom all make such devices. You can also add Modbus-TCP to a ControlLogix with a card from Prosoft Technology that plugs right into the backplane.

-James Ingraham
Sage Automation, Inc.

Peter Chipkin

You are correct. Just because the protocols are carried in TCP/IP packets doesnt mean they are compatible. The message formats and payloads are quite different as are the addressing schemes.

You do not have to make a choice. You can integrate the two devices using a protocol gateway.


Peter Chipkin
No, and Yes.

Yes, you can have both types of devices on the same Ethernet network at the same time.

No, they do not use Ethernet packet rules, there is no such thing. They both use Internet Protocol rules: TCP/IP and UDP/IP. Use of IP protocols allow completely independent operation as long as they do not load the network excessively.

Dick Caro
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Lynn A Linse

While they can co-exist, Modbus/TCP and Ethernet/IP won't dirrectly talk since the packet format is different. It's not that hard to add enough Ethernet/IP to support the older PCCC (DF1-like) commands, but you won't have that option if you're just using off-the-shelf equipment.

My Digi One IAP happliy bridges between the two and I'm hoping others start erasing this barrier as well. We just assume 4x00001 under Modbus references N7:0 on the AB and so on. There doesn't need to be this incompatibility; of course don't expect Rockwell to add Modbus/TCP, but small vendors who now only support Modbus/TCP could add enough
Ethernet/IP to interoperate with Rockwell equipment without the needs for external boxes.

best regards
- LynnL,

Charlie Peterson

Hello Michael,

FieldServer Technologies will provide you with an embedded device (ProtoCessor) which will enable your single protocol product to communicate with other devices which speak various other protocols (like Modbus TCP to Ethernet IP).

For additional information, please visit: or call me at: 800-317-8319.

Best Regards,
Charlie Peterson
[email protected]