How to Improve Communication on Allen-Bradley Legacy PLC-5s and SLC 5/04s

Industrial automation, Allen-Bradley legacy controllers such as the PLC-5 and SLC 5/04 remain staples in facilities across North America. Despite their age, these devices continue to support critical operations, and ensuring reliable and modern communication with them is more important than ever. Whether for plant upgrades, SCADA integration, or troubleshooting, improving the communication pathway to these controllers brings long-term benefits. This guide offers a comprehensive approach to enhancing data exchange with legacy PLCs by utilizing modern protocol converters like the ANC-100e and ANC-120e.

Understanding the Challenge

The PLC-5 and SLC 5/04 both communicate using the Data Highway Plus (DH+) protocol, a robust but aging communication standard. Most modern PCs, HMIs, and SCADA systems no longer natively support DH+. Additionally, RS-232 and 1784-KTx cards are becoming obsolete and increasingly difficult to source. Integrators are therefore challenged with bridging legacy systems to modern Ethernet-based infrastructure.

Solution Overview: ANC-100e and ANC-120e Converters

Automation Networks offers two powerful solutions: the ANC-100e (Ethernet to DH+) and the ANC-120e (USB to DH+). These devices serve as protocol converters, enabling modern devices to communicate with legacy controllers via the DH+ network. Both models support features like auto baud rate, auto node assignment, and polarity detection, dramatically simplifying configuration.

The ANC-120e is ideal for laptops or workstations needing quick, mobile access via USB. The ANC-100e, on the other hand, provides a more permanent Ethernet solution suitable for SCADA and HMI integration.

Step-by-Step: Improving Communication

1. Hardware Integration: Begin by connecting the ANC-100e or ANC-120e to your DH+ network. The DH+ port on PLC-5 and SLC 5/04 controllers can be accessed via the 3-pin Phoenix connector or the Mini-DIN programming port. Both converters support automatic polarity detection, so cable orientation is not a concern.
2. Device Configuration: Using the device’s web interface, accessible through a browser, assign a static IP address for the ANC-100e (default is 192.168.0.230) or ANC-120e (default is 192.168.137.2). Set your PC’s network adapter to a matching subnet to gain access. Once connected, login using the default credentials (admin/password) and configure HMI tabs or diagnostic settings as needed.
3. Driver Installation and Software Setup:
   • For ANC-120e: Install the RNDIS driver for Windows (preinstalled in Windows 7+). For newer Windows versions, download drivers from the Automation Networks website.
   • For ANC-100e: Ensure your PC or SCADA workstation is configured with a compatible static IP.
4. Using RSLinx Classic or Enterprise.
   Within RSLinx Classic:
   • Open “Configure Drivers”.Select “Remote Devices via Linx Gateway”.Enter the ANC device IP.Launch RSWho and Autobrowse. The connected DH+ devices should appear under Channel A.
   Within FactoryTalk Linx:
   • Create a new application and communication driver.
   • Use the ANC HMI tab to assign virtual Ethernet links to DH+ nodes.
   • Add your SLC 5/04 or PLC-5 as Ethernet devices.
5. Ignition, AVEVA, and PanelView 7 Plus Integration.
   For Ignition:
   • Use the OPC-UA server.Select Allen-Bradley SLC or PLC5 driver.Use the ANC IP as Hostname and set Connection Path as 1,1,2,<DH+ node>.
   For AVEVA InTouch:
   • Use the ABCIP driver.Define the ANC device under the ENB_CLX path.Configure DHRIO and DH+ node pathing for the PLC.
   For PanelView 7 Plus:
   • Access ANC HMI tab.
   • Assign IP/DH+ node mapping.
   • Use Ethernet SLC/PLC device templates in RSLinx Enterprise.
6. SLC 5/05 to SLC 5/04 Messaging Over DH+: With an ANC gateway, you can message from an Ethernet-enabled SLC 5/05 to a DH+ SLC 5/04. Use MultiHop routing:
   • Setup the MSG block in RSLogix.
   • Define channel 1 for Ethernet.
   • Use hops: EtherNet/IP to ANC IP, backplane slot, DHRIO channel, and DH+ node.

Best Practices

• Assign unique node addresses across all DH+ devices.
• Use surge-protected power supplies for ANC-100e.
• Ensure matching baud rates or use auto-baud for simplicity.
• Always verify RSWho tree to confirm proper DH+ topology.

By integrating ANC-100e or ANC-120e adapters, engineers can bridge decades of technology, enabling reliable communication between modern software and legacy Allen-Bradley PLC-5 and SLC 5/04 hardware. These converters offer a low-cost, plug-and-play solution that minimizes downtime and extends the life of critical control assets. Whether for development, HMI access, or full SCADA integration, Automation Networks’ protocol converters offer unmatched ease of use, reliability, and flexibility.