Remote I/O (RIO) has been a defacto communications protocol for Allen Bradley (Rockwell) PLCs and automation products for many years. My first network with RIO was in 1995. Many B&D Technologies Engineers and integration partners have utilized this protocol since its inception many years ago. The current challenge is the protocol is obsolete and users are being forced to upgrade their designs. It is kind of like a quasi-monopoly, dictating to users that they only have one (immensely expensive) upgrade option.

B&D Technologies decided to work with our partner SoftPLC to develop our own RIO adapter for non-AB drives. With specific emphasis on ABB ACS880 and DCS880 (DCS800) drives.


Here is a partial list:

  • The adapter is a single drop option board that is tiny— it fits as an option card on the ABB ACS880 and DC drives as if it is a factory option card
  • It allows the user to create a ¼, ½, and full rack look and feel of the original AB design. The other side is Modbus TCP/IP or Modbus RTU interface for ABB and other drives types that have Modbus as a standard protocol
  • All of a sudden, the RIO adapter allows for a true high-performance drive to be added to a AB/Rockwell network that used to be proprietary
    • High-performance – OK, here is an opinion: As far as performance, Rockwell uses a drive that is akin to the ABB ACS500 drive from 20 years ago. They still live in the world of PWM
    • DC Drives – Well, Rockwell has not made their DC drive in many years and use an Italian company that has a mere fraction of global market share. We replace several of their new DC drives each year for various reasons. Again, it is like stepping back in time to work on a drive that I serviced 20 years ago
  • The adapter is portable and can be used as an option board on the drive or is Din-rail mounted

Final Words

There are several companies, including SoftPLC (the key one), that offer the ability to create a RIO server or multiple drop network adapter. The challenge is to be able to complete a drive replacement one at a time, without the massive investment of larger, more expensive components, coupled with potential network changes. The B&D Technologies RIO adapter card allows us and the user to break the chains of proprietary networks and provides users the freedom to make their own choices and include significantly higher performance products in their designs.

We will keep everyone posted as we are into the prototype stage and are working with our strategic integration partners for additional testing.

If you are interested in being a beta-site for testing, B&D will provide a sample ABB Drive and B&D RIO card on your AB/Rockwell network.  This includes the engineering to make the drive work correctly.

If this sounds like music to your ears, contact us at

CTolbert DOE