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Ethernet remote I/O for a SLC 5/05
I would like to use ethernet remote I/O with AB SLC 5/05 PLC's. My AB rep says "no can do". Any sugestions?
By Jeff Holmes on 1 May, 2002 - 10:27 am

I know that plenty of companies make ethernet remote I/O but my AB rep says that the ethernet port on the SLC 5/05 is for programming only and there is no product available which will interface ethernet I/O with the SLC. I can't believe this could be true, surely somebody makes an interface that will work. Can somebody give me a suggestion?

By James Ingraham on 1 May, 2002 - 1:08 pm

It appears it is true. You could theoretically put a PC and some I/O on the same Ethernet network and have the PC send data back and forth between the two. This seems rather pointless to me. You could also use some other network that the SLC does support (including DF1) and go to a controller that supports Ethernet I/O schemes, e.g. a ControlLogix or a ProLinx Gateway.

-James Ingraham
Sage Automation, Inc.

By Eddie Willers on 1 May, 2002 - 1:20 pm

I use SLC-5/05's every day and I'll second your rep: "no can do".

The SLC-5/05 implements only the "peer to peer" parts of the older A-B PCCC protocol. It's a capable small controller, and very popular, but all of the communication and control is serviced by one 68020 microprocessor it just doesn't have the horsepower to do Ethernet I/O as well as run the backplane and control routines.

Rockwell put their development efforts for EtherNet/IP into the ControlLogix line;
the controller onboard the 1756-ENBT is much more powerful than the whole SLC, and that module came out only a few months ago.

By Peter Nachtwey on 2 May, 2002 - 10:43 am

> I know that plenty of companies make ethernet remote I/O but my AB rep says that
> the ethernet port on the SLC 5/05 is for programming only

The SLC5/05 is NOT for programming only. SLC5/05 Ethernet can talk to other AB Ethernet enabled PLCs and AB Ethernet compatible motion controllers. Our motion controller can mimic a SLC5/05 when accessed by other AB Ethernet products.

> and there is no product available which will >interface ethernet I/O with the SLC.

The SLC5/05 can only use MSG blocks.

>I can't believe this could be true

It is true if you are talking about mapping I/O over the Ethernet. There are a few device that communicate with SLC5/05 using MSG blocks.

>surely somebody makes an interface that will work. Can somebody give me a suggestion?

By Steve Young on 3 May, 2002 - 5:21 pm

The real issue you have is that AB it appears really does not want ethernet to succeed, and if it does, only if they can keep it proprietary using the controlnet protocol over ethernet.

For a more complete list of manufactures with modbus ethernet try "": .

By ScienceOfficer on 7 May, 2002 - 10:39 am


This is untrue and offpoint. A-B has supported Ethernet since the Eighties, and has shipped thousands of Ethernet nodes. Ethernet/IP
enhances Ethernet without removing anything that came before --- and as has been well explained in other posts, the 5/05 has simply not been upgraded to handle the real-time I/O feature of Ethernet/IP.

All the A-B Ethernet products still do everything they have always done--- providing high-speed links among processors, HMIs, and programming terminals. Nothing has been removed. Future and upgraded products will roll out the enhanced features of Ethernet/IP.

Hope this helps!

Larry Lawver
Rexel / Central Florida

Right now I have an Cimplicity HMI that talks to an SLC 5/05 over ethernet. There are some restrictions on what files you can read/write to, but that's about it. You need RSLinx OEM to do it, because it includes APIs that Cimplicity relies on for data access. If you're writing a custom app, you could do the same thing.

Not true, check out Acromag Ethernet/IP IO. You can connect to these devices using legacy SLC505 however obviously using PCCC messaging over ethernet. None the less, these devices can provide ethernet IO for remote monitoring and non critical control for example.

By Don Lupo on 5 June, 2009 - 8:05 am

Here's a link to connecting Acromag's Ethernet IP I/O to the SLC 5/05 via PCCC. The Acromag Ethernet IP devices support straight Ethernet IP, PCCC, and Modbus TCP/IP all in one unit.

If any questions or I can assist, please let me know.

Kind Regards,
Donald Lupo (

By James Ingraham on 5 June, 2009 - 12:32 pm

Perhaps "No longer true" would be a better statement? The thread took place in 2002. That Acromag now has a solution is pretty cool, but it doesn't change the state of affairs 7 years ago.

In fact, when I saw the post this time around I thought, "Just replace the PLC!" That's probably a good answer now, but wasn't back when ControlLogix was relatively new and CompatLogix didn't exist and the PLC wasn't that old...

-James Ingraham
Sage Automation, Inc.

By Bob Peterson on 7 June, 2009 - 12:04 pm

Have you considered using a uL1100 as the remote I/O?

You can message to/from the 1100. Won't work if you need really fast
updates, but for run of the mill monitoring, its a cheap and easy solution.

By Patrick Lansdorf on 9 June, 2009 - 2:30 am

Hi Jeff,

One way to go, could be to use a gateway. If the SLC has DeviceNet or Controlnet scanner capabillaties, you could use a gateway from Devicenet/Controlnet to Ethernet/IP.

For more info go to: X-gateway

or X-gateway

If you have any technical questions, let me know at: support [at]

Patrick L