1769-AENTR: 2nd port for PLC access?

My client wants to use a new 5069-L320ER to replace a Micro1500, but wants to keep the 1769 I/O. Planning on using the 1769-AENTR for a 1769 remote rack. Will I be able to program the PLC from the 2nd unused port on the 1769-AENTR?

I would think you can since the dual ports on the 1769 compacts work as a passthrough, but I want to confirm before I tell them they can get by without adding a switch.

Yeah you should be fine. Pretty sure the AENTR is meant for a RING topology, but you dont have to follow that. The second port should act like a free LAN port.

Pretty sure I've done if on a project where the original OEM did not leave a single spare port on a sub panel, and they had a 1734-AENTR with an open port I was able to put another device on... worked fine

Plus, doesn't the 5069-L320ER have 2 ethernet ports?
You get one to connect to the AENTR and a spare

If my memory serves me right, the M1500 does not have ethernet currently...
You'll probably have 2 spare Enet ports

Yes, the 5069 does have 2 ports, but 1 will go to the AENTR, the other will go to the plant network connection. I just need 1 local programming port.

I have 2 places where I do that. It's just a switch. I would imagine its intended for DLR but I have not used it for that.

Yes, you can do this. I almost always spec AENTR's over AENT's because if it's in a remote panel, it gives me an automatic programming port at that panel.

Of course at my MCC I would just spend the money on a switch even if there are only two devices, but that wasn't your question.

In general, an A-B Logix-family device with an "R" in the last position of the model code indicates it has an embedded switch that supports Device-Level Ring functionality.

5069-L320ER
1769-AENTR
1734-AENTR
1756-EN2TR

Even if you're not using DLR, you can use such embedded switches to build a "daisy chain" or "linear" network. That includes using one port to connect to the PLC controller, and the other to connect your HMI or PC workstation.

The 5069 family CompactLogix controllers are special in that they support both DLR/Linear mode as well as two independent IP addresses.

So the basic answer to Ian's question is: "yes, that will work".