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Options for Interfacing Older DH+ PLC5s and SLC 5/04s to the Latest Ethernet Products

Many factory users are looking for a solution to interface their older AB PLC5s and SLC 5/04s on AB DH+ to communicate with newer Ethernet AB PLCs. Like the SLC 5/05 and PLC 5-Es, and perform RSLINX /LOGIX PLC programming via Ethernet.

Which PLC5 do you have? 

Choosing your solution will depend on whether you have an older original PLC5 or the next generation PLC5s as per below:

The original AB PLC5/10, 5/12, 5/15, & 5/25 have 2 communication ports which include Allen-Bradley Data Highway Plus or AB Remote (RIO)

The next generation of the PLC-5 processors include 5/11, 5/20, 5/30, 5/40, 5/60, 5/80, which have Data Highway Plus and Remote I/O ports, and a 25 pin RS232 communication with DF1 protocol with the option of ordering with an Ethernet or ControlNet port.

What are my Ethernet to DH+ options?

If you are wanting to keep your existing DH+ PLCs5 and SLC 5/04s in your current installation and want to interface newer Ethernet devices, here are a couple of options.
ANC-100e: Ethernet/IP to DH+ Converter

ANC-100e (Ethernet/IP to DH+)

ANC-100e, RSLINX Ethernet/IP to Allen-Bradley Data Highway Plus Gateway Converter Series. $1,295 USD List.   The ANC-100e is an economical and high performance, “pocket-sized” converter interfacing Factory Automation Devices between Ethernet/IP and PLC-5s & SLC-504s on Allen-Bradley Data Highway Plus.

ANC-100e Product Review from  https://theautomationblog.com/data-highway-plus-to-ethernet/

ANC-120e: USB to DH+ RSlinx PLC

ANC-120e (USB to AB DH+)

ANC-120e, USB to AB Data Highway Plus RSLINX PLC Programming Cable, alternative to the 1784-U2DHP. $1,295USD List. This high performance cable uses the AB Controllogix Ethernet Driver for fast communications access to PLC-5 & SLC 5/04s


AB Controllogix Gateway 1756-DHRIO Processor 

AB Controllogix Gateway 1756-DHRIO Processor 

Controllogix 1756 DH+ to Ethernet Gateway that is used to bridge from Ethernet to 2 Data Highway Plus networks at speeds of 57.6Kb, 115.2Kb and 230.4Kb.

The Benefits of the 1756 is that it allows one Ethernet Gateway to many networks including ControlNet, Devicenet, DH+, DH-485.  It has direct access to PLC-5 Data Tables with no programming required to bridge from Ethernet to DH+.

Unfortunately, this is an expensive single solution for your PLC5 on DH+:

1756 Package:



1756-PA75: 85-265V AC POWER SUPPLY


EtherNet/IP Converter to Allen Bradley Remote I/O or DH+ Gateway

EtherNet/IP Converter to Allen Bradley Remote I/O or DH+ Gateway

Prosoft’s AN-X2-AB-DHRIOis an EtherNet/IP to Remote I/O or Data Highway Plus converter, that is designed to help customers initiate a phased migration approach to replacing or upgrading legacy Remote I/O, HMI’s or Drives. 

It is a flexible gateway that works with most Ethernet equipment allowing messaging between RSLINX/LOGIX to DH+ or communciations between newer AB Ethernet PLCs to older PLC5s and SLC 5/04s on DH+.

AB 1761-Net-ENI DF1 to Ethernet/IP converter

AB 1761-Net-ENI DF1 to Ethernet/IP converter

This solution will allow your RS232, DF1 CH0 serial port on your PLC5 communication path to AB Ethernet/IP.

The benefits of this solution is that it is the least expensive option and have direct access to the PLC5 Data Table with built in email capabilities and ENI configuration done with a free utility.

Limitations include allowing only 3 of the same bi directional connections to the PLC5 at any given time.  The PLC5 serial port only has serial communication speeds of 19.2Kb.

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