CC-Link IE Field Basic to EtherNet/IP Gateway for Robot Integration
Modernizing a production line often means integrating new equipment with legacy control systems. When an automotive welding shop needed to connect EtherNet/IP robots to a Mitsubishi CC-Link IE Field Basic PLC, a protocol conversion gateway provided a fast, cost-effective solution. This article explores the technical details, configuration steps, and real-world results of such an integration.
The Challenge: Merging Two Industrial Networks
A vehicle body welding workshop in East China faced a common automation dilemma. The existing control system was built around a Mitsubishi MELSEC iQ-R series PLC (model R04CPU) using CC-Link IE Field Basic protocol. This network reliably managed remote I/O, servo drives, and welding power sources. The upgrade plan called for adding several six-axis welding robots that only supported EtherNet/IP. Replacing the main PLC would have been expensive and caused significant downtime. Instead, engineers opted for a protocol gateway to bridge the two networks.
Key Components in the Integration
| Device | Role | Protocol |
|---|---|---|
| Mitsubishi R04CPU PLC | Main controller | CC-Link IE Field Basic (master) |
| Protocol Conversion Gateway | Bridge between networks | EtherNet/IP master / CC-Link IE FB slave |
| FANUC Welding Robots (x3) | New welding actuators | EtherNet/IP slave |
| Hirschmann Switch | Network infrastructure | Industrial Ethernet |
Network Topology: A Hybrid Star-Ring Design
The system used a hybrid star-ring topology to ensure reliability and future expansion. On the CC-Link IE Field Basic side, the Mitsubishi PLC’s built-in Ethernet port connected to the gateway via the Hirschmann switch. The gateway was configured as a slave station with station number 5, occupying 256 bytes of input and 256 bytes of output. These were mapped to PLC soft elements D5000-D5255 (inputs) and D6000-D6255 (outputs).
On the EtherNet/IP side, the same gateway acted as the master, scanning the three FANUC robots. Each robot was allocated 128 bytes of input and 128 bytes of output. The gateway’s internal data mapping ensured bidirectional data flow between the two networks.
Step-by-Step Configuration
1. Hardware Installation
The gateway was mounted on a DIN35 rail with 24VDC independent power. Shielded twisted-pair cables connected both network interfaces. A steady green PWR LED indicated proper power.
2. Gateway Configuration (via JetCfg V3.1.2)
- Created a new project and selected the gateway model.
- Configured EtherNet/IP as master, adding three slaves (robots) with 128 bytes I/O each.
- Set CC-Link IE FB as slave, station 5, with 256 bytes I/O.
- Built data mapping: Robot 1 inputs to D5000-D5127, Robot 2 to D5128-D5255, Robot 3 to D5256-D5383; outputs mapped similarly to D6000-D6383.
- Downloaded configuration; a steady green RUN LED confirmed normal operation.
3. PLC Configuration (GX Works3)
- Opened “Ethernet Configuration” → “CC-Link IEF Basic” and added a remote station (station 5, 256 words).
- Assigned D5000-D5255 as remote inputs and D6000-D6255 as remote outputs.
- No FROM/TO instructions needed; the PLC automatically refreshed data cyclically.
4. Robot Configuration (FANUC ROBOGUIDE)
- Set EtherNet/IP slave parameters with 128 bytes I/O.
- Mapped signals: weld start, complete, fault, position reached, etc.
- Monitored signal status via Teach Pendant to verify consistency with PLC data.
Control Logic and Data Flow
The PLC used the D6000 output area to send welding program numbers, start commands, and parameters (current, voltage, speed) based on vehicle type identification. Robots executed the trajectories and returned status, fault codes, and actual welding time to the D5000 input area.
Safety interlocks were implemented: if a robot alarm occurred (e.g., torch collision, servo fault), the PLC immediately halted subsequent welding commands and triggered a buzzer and HMI pop-up. For quality traceability, after each weld, the PLC packaged parameters and results and uploaded them to the MES via an upper computer interface.
Performance Results and Benefits
| Metric | Result |
|---|---|
| Communication Stability | Zero faults over 6 months, MTBF > 50,000 hours |
| Cycle Time Improvement | Robot response time reduced by 30%; station cycle from 52s to 41s |
| Commissioning Time | Only 4 days from hardware installation to production |
| Cost Savings | Avoided PLC replacement and program rewrite, saving ~600,000 RMB |
| Scalability | Ready to add more EtherNet/IP devices (vision systems, laser cleaners) |
Why Protocol Gateways Are Essential for Modernization
This case demonstrates the value of industrial protocol gateways in brownfield automation projects. Instead of a costly rip-and-replace, a gateway enables legacy systems to communicate with modern equipment. The approach preserves existing investments while unlocking new capabilities like robotic welding, data collection, and MES integration.
When selecting a gateway, consider factors like supported protocols, data mapping flexibility, configuration software ease-of-use, and industrial certifications. The device used here provided a transparent bridge with minimal latency, ensuring real-time control was not compromised.
Key Takeaway: Protocol conversion gateways are a proven solution for integrating EtherNet/IP devices into CC-Link IE Field Basic networks. With proper configuration, they deliver reliable, high-speed communication and can be deployed in days, not weeks.
