Kepserver EX: Ethernet to DH+ PLC-5 & SLC 5/04 Communications with the ANC-100e8m
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Many industrial facilities are facing a major challenge: legacy Allen-Bradley PLC-5 and SLC 5/04 controllers are still running critical processes, but Rockwell’s RSLogix and RSLinx ecosystem is becoming increasingly expensive, difficult to maintain, and in some cases no longer supported.
Replacing these PLCs with ControlLogix systems can cost hundreds of thousands or even millions of dollars in hardware, engineering, downtime, and validation.
However, there is a much more cost-effective strategy: keep the legacy PLCs running on DH+ (Data Highway Plus) and connect them to modern Ethernet networks using an ANC-100e DH+ to Ethernet gateway combined with KEPServerEX. This approach allows plants to modernize communications, SCADA, databases, and remote access without replacing the PLC hardware.
The Legacy PLC Problem
Across North America and Mexico, thousands of plants still operate:
- PLC-5 processors
- SLC 5/04 processors
- DH+ blue hose networks
- PanelView Standard terminals
- Old SCADA systems tied to RSLinx
- PLC-5 processors
- SLC 5/04 processors
- DH+ blue hose networks
- PanelView Standard terminals
- Old SCADA systems tied to RSLinx
These systems are extremely reliable and often control processes that have been running for 20–30 years. The problem is not the PLCs themselves — the problem is communication and software support.
Common issues companies face today include:
- RSLinx - licensing costs
- RSLogix - software no longer supported
- Difficulty - connecting old PLCs to modern SCADA
- No easy way to send data to databases or cloud systems
- No remote access over Ethernet/VPN
- Integrating legacy PLC data into Ignition, OPC UA, or SQL
- RSLinx - licensing costs
- RSLogix - software no longer supported
- Difficulty - connecting old PLCs to modern SCADA
- No easy way to send data to databases or cloud systems
- No remote access over Ethernet/VPN
- Integrating legacy PLC data into Ignition, OPC UA, or SQL
Replacing PLC-5 or SLC systems just to get Ethernet connectivity is usually unnecessary and extremely expensive.
The Alternative: Keep DH+, Add Ethernet
Instead of replacing the PLC hardware, a much smarter approach is:
Keep the PLC-5 and SLC 5/04 on DH+
Use ANC-100e to bridge DH+ to Ethernet
Use KEPServerEX as the communication platform
This architecture allows legacy PLCs to communicate with modern systems like:
Ignition SCADA
Wonderware
FactoryTalk
OPC UA clients
SQL databases
MES systems
Cloud platforms
Remote monitoring systems
All without replacing the PLC.
What the ANC-100e Does
The ANC-100e is a DH+ to Ethernet communication gateway. It connects directly to the DH+ network (blue hose) and converts DH+ communications into Ethernet protocols such as Ethernet/IP or TCP/IP.
This means devices on Ethernet can communicate with PLC-5 and SLC processors as if they were on a modern network.
The ANC-100e essentially becomes a bridge between two worlds:
Legacy
Modern Alternative
DH+
Ethernet
PLC-5
SCADA
SLC 5/04
Databases
PanelView
Cloud
Blue Hose
VPN/Remote Access
Where KEPServerEX Fits
KEPServerEX is one of the most powerful industrial communication platforms available. It acts as an OPC server and communication hub that can connect to hundreds of different PLCs and systems.
When used with the ANC-100e, the architecture typically looks like this:
PLC-5 / SLC → DH+ → ANC-100e → Ethernet → KEPServerEX → SCADA / Database / Cloud
KEPServerEX can then expose the PLC data through:
OPC DA
OPC UA
MQTT
REST
SQL logging
IoT Gateway
Ignition
MES systems
So instead of every system needing to talk directly to the PLC, everything talks to KEPServerEX.
Replacing legacy PLC systems can be extremely expensive.
Let’s compare the two approaches.
Option 1 – Replace PLC-5 System
Typical costs:
ControlLogix PLC: $8,000 – $15,000
Remote I/O conversion: $10,000 – $40,000
Engineering time: $20,000 – $100,000
Downtime: Very expensive
Revalidation: Very expensive
Total project cost often: $75,000 – $300,000 per system
Option 2 – Keep PLC-5 and Modernize Communications
Typical costs:
ANC-100e gateway
KEPServerEX license
Ethernet infrastructure
Minimal engineering
Total project cost often: $5,000 – $15,000
This is often 90% cheaper than replacing the PLC system.
Benefits of Using KEPServerEX with ANC-100e
1. Extend PLC Life 10–15 Years
PLC-5 and SLC processors are extremely reliable. The real problem is communication and software, not the PLC hardware. By adding Ethernet connectivity through ANC-100e and KEPServerEX, these PLCs can continue running for many more years.
2. Connect to Modern SCADA Systems
KEPServerEX can connect the legacy PLCs to:
Ignition SCADA
FactoryTalk
Wonderware
Citect
WinCC
AVEVA
Custom HMI systems
This allows plants to upgrade SCADA without replacing PLCs.
3. OPC UA Connectivity
OPC UA is the modern industrial communication standard. KEPServerEX provides OPC UA connectivity, allowing legacy PLC data to integrate with modern systems securely.
4. Database Logging
KEPServerEX can log PLC data directly to:
SQL Server
MySQL
PostgreSQL
Oracle
This is extremely useful for:
Production tracking
OEE
Quality data
Maintenance data
Energy monitoring
5. MQTT and IIoT Integration
With the IoT Gateway module, KEPServerEX can publish PLC data via MQTT to:
Cloud systems
AWS
Azure
Ignition MQTT
Sparkplug B systems
This allows legacy PLCs to become part of Industry 4.0 architectures.
6. Remote Access Over VPN
Once the PLC data is available on Ethernet through the ANC-100e and KEPServerEX, remote access becomes easy through VPN or secure networks.
This allows:
Remote troubleshooting
Remote monitoring
Remote data collection
Reduced travel costs for engineers
Typical System Architecture
Many plants are now realizing that replacing PLC-5 and SLC systems is not necessary just to get Ethernet connectivity.
Do not replace PLCs because of communications.
Modernize the communications and keep the PLCs running.
This approach:
Saves money
Reduces downtime
Reduces engineering risk
Extends equipment life
Enables Industry 4.0 connectivity
Allows gradual modernization instead of full system replacement
Large companies are now doing exactly this across multiple plants.
Real-World Example
Before:
PLC-5 on DH+
PanelView Standard
RSLinx Classic
Old SCADA
No database logging
No remote access
After adding ANC-100e + KEPServerEX:
PLC-5 still on DH+
Ignition SCADA
OPC UA server
SQL database logging
Remote monitoring
MQTT to cloud
VPN remote access
Reporting dashboards
This is a huge improvement at a fraction of the cost.
Using KEPServerEX with the ANC-100e is one of the most cost-effective ways to modernize legacy PLC-5 and SLC 5/04 systems that still operate on DH+ networks.
Instead of replacing reliable PLC hardware, plants can extend the life of these systems while gaining modern Ethernet connectivity, SCADA integration, database logging, remote access, and Industry 4.0 capabilities.
This strategy can reduce modernization costs by up to 90%, minimize downtime, and allow facilities to gradually upgrade their automation systems over time instead of performing expensive full system replacements.
For many facilities, the smartest path forward is not replacing legacy PLCs — it is connecting them to modern networks using gateways like the ANC-100e and communication platforms like KEPServerEX.
Modernize the network, not the PLC.
Data Highway Plus to Ethernet (S02)
In today’s episode of The Automation Show, I unbox and setup an ANC-100e Data Highway Plus (DH+) to Ethernet Converter Data Highway Plus to Ethernet bridge from Automation Networks. For more information about the show (and how you could win an ANC-100E) check out the “Show Notes” located below the video. The Automation Show, Episode 2 Show Notes: NOTE: Would you like your … Continue readingData Highway Plus to Ethernet (S02)
