View Full Version : SLC 5/05 To Remote IO

August 23rd, 2002, 08:17 AM
Just wondering if anyone knows of a way to connect an AB SLC 5/05 to remote IO using Ethernet. I haven't found any Ethernet IO from AB. Does anyone know another manufacturer that has this type of product that will interface easily with SLC? Only viable communication options I have found are Devicenet, ControlNet, Universal Remote IO, etc... Any suggestions are appreciated.

August 23rd, 2002, 08:33 AM
Are you looking for a "ethernet to RIO" converter, or Ethernet I/O?

August 23rd, 2002, 08:43 AM
Preferably remote ethernet IO. What I had in mind would be something like Flex IO only using Ethernet instead of Devicenet or Universal Remote IO.

Allen Nelson
August 23rd, 2002, 08:57 AM
The only way that the SLC has to read it's channel 1 (ethernet port), is by the MSG command. The remote I/O would have to behave like a PLC, interpreting a request for data from a "Data Table Offset", and replying with the info.

I'm not saying there isn't such a device, but I haven't heard of one.

August 23rd, 2002, 11:18 AM
Originally posted by K.C.

I haven't found any Ethernet IO from AB.

1794-AENT A FlexI/O Ethernet/IP adapter.I dont think that it will work with 5/05, but there is AB ethernet I/O.

August 23rd, 2002, 12:50 PM
To connect to RIO from a SLC5/05, you'll need a Remote I/O scanner module in your PLC rack.

I don't know of any device that will convert the ethernet messages to Remote I/O. If you're planning to do some searching for third-party solutions, keep an eye out for "Control IP." That's the ethernet protocol that the SLC 5/05 uses (I think). It's different from TCP/IP. At least, that's what I understand. I could be talking out of my rear-end.


Ken Roach
August 24th, 2002, 01:02 AM
I understand what's being asked: "Hey, the SLC-5/05 has an Ethernet port, and some manufacturers are selling Ethernet-based I/O modules now. Can I use that I/O, dispense with the special I/O scanner cards, and steal all my physical media from the old server closet ? "

The short answer is no.

The long answer is also no, but it's because the SLC is a nice mature control platform with enough sense to not go running off after the latest network media or protocol fad. It's nights like this I'd like to track down the jerk who wrote that puff piece in Managing Automation last year about Calloway Golf's choice of Ethernet I/O: "...I won't buy anything that won't let me assign an IP address....". That magazine would be worth more if they printed it on absorbent paper so I could wipe my butt with it. banghead

Fear not, K.C., my rant time is over and here's the straight scoop:

The SLC only uses it's 10BaseT Ethernet port for unscheduled messaging to peer controllers, operator interface terminals, and software interfaces for programming and monitoring. It implements the Rockwell proprietary "Client-Server Protocol" (PLC-5E have used this for years) as well as part of the Information portion of Rockwell's "Control and Information Protocol" (CIP).

It does not implement the Control part of CIP. Although you can send MSG instructions out the Ethernet port from ladder logic, they're exclusively for peer-to-peer communications between controllers.

Several of the ControlLogix family of controllers do implement this functionality, and Rockwell is building EtherNet/IP protocol adapters for most of their modular I/O products (FLEX, Point, Compact, etc).

The SLC just doesn't have the processor horsepower in it's communication daughterboard to work as an Ethernet I/O scanner. I like the SLC-5/05 and work with it all the time, but the architecture isn't built for a high-speed communication interface on the front port, and and the product line is old enough that Rockwell is going to put their development efforts into the ControlLogix and let the SLC do what it does well.

Peter Nachtwey
August 24th, 2002, 02:03 AM
K.C. The practical answer is NO! One probably could get a bridge and convert SLC Ethernet packets to Modbus/TCP packets but you would be paying a lot of money for a slow and second rate solution.

The Ethernet protocol that SLC use is not a simple protocol. I doubt that the SLC5/05's CSP ( client servero protocol ) will ever implemented in cheap I/O blocks because it would be too expensive and still be the wrong answer.

Ethernet I/O should not use TCP/IP like the SLC5/05's message blocks use. Ethernet I/O should use UDP as in Rockwell's Ethernet/IP or raw Ethernet packets like Automation Direct.

Ken, are you feeling better? I can see you stopped banging your head.

August 24th, 2002, 04:47 PM
Thanks for all the replys. We're just going to stick in a ML 1500 and be done with it. At least now | have a better understanding of AB Ethernet. Thanks again to all who responded.

March 10th, 2003, 02:17 PM
We had this same situation and found a solution. We put in a Proface GLC HMI. It had the driver for the SLC5/05 via Ethernet and had a PLC with FlexIO built in. Cheaper than another SLC5/05