Integrate Siemens S7-1200 with Inovance EtherCAT Servo via Protocol Gateway
Application Scenario: Many automation systems face a protocol mismatch between the controller and drives. For instance, a Siemens S7-1200 PLC natively supports Profinet, while high-performance servo drives like the Inovance SV660 series use EtherCAT. Instead of replacing the PLC, a protocol gateway can bridge the two networks transparently.
System Architecture Overview
The solution uses a Profinet-to-EtherCAT gateway that acts as a Profinet device on one side and an EtherCAT master on the other. The S7-1200 sends standard Profinet telegrams to the gateway, which converts them into EtherCAT frames to control the SV660 servo. Feedback data follows the reverse path. This setup maintains real-time performance and simplifies integration.
Typical Network Topology
- Controller: Siemens S7-1200 CPU (Profinet IO Controller)
- Gateway: Profinet Device to EtherCAT Master (e.g., WL-PN-ECATM)
- Drive: Inovance SV660N servo drive (EtherCAT Slave)
- Motor: Servo motor with encoder feedback
Prerequisites and Hardware Setup
Before configuration, ensure the following:
- The Inovance servo drive is correctly wired, powered, and its rotary switches are set to EtherCAT mode (usually default).
- The gateway firmware is up to date.
- You have obtained the GSDML file for the Profinet-to-EtherCAT gateway from the manufacturer.
- All devices are on the same physical network segment or properly routed.
| Component | Example Model | Role |
|---|---|---|
| PLC | Siemens S7-1200 CPU 1214C | Profinet IO Controller |
| Gateway | WL-PN-ECATM | Profinet Device / EtherCAT Master |
| Servo Drive | Inovance SV660N | EtherCAT Slave (CoE) |
Step-by-Step Configuration in TIA Portal
1. Install the GSDML File
Download the GSDML file for the gateway. In TIA Portal, go to Options → Support packages → Install GSD file. Browse to the file and install it. Restart TIA Portal to refresh the hardware catalog.
2. Configure the Profinet Network
Create a new project and add your S7-1200 CPU. Open the Network view. From the hardware catalog, navigate to Other field devices → PROFINET IO → Gateway → PN-ECAT. Drag the device into the network view and connect it to the PLC’s Profinet port.
Assign a unique device name (e.g., “pn-ecat”) and an IP address in the same subnet as the PLC (e.g., 192.168.20.18). Double-click the gateway to open its Device view. Configure the I/O data lengths:
- Inputs: At least 8 bytes for servo feedback (status word, actual position).
- Outputs: At least 8 bytes for control commands (control word, target position).
For advanced motion, 32 bytes input and 32 bytes output are typical.
Note: The I/O sizes must match the process data mapping configured in the gateway’s EtherCAT manager later.
3. Configure the Gateway as EtherCAT Master
Connect your PC to the gateway’s configuration port. Use the manufacturer’s EtherCAT configuration tool (e.g., EtherCAT Manager). Add the PN2ECAT device and set its IP address and name to match the TIA Portal settings. Then scan for EtherCAT slaves or manually add the Inovance SV660 drive using its ESI file.
Map the process data objects (PDOs) between the gateway’s internal memory and the servo’s CoE objects. Typical mappings include:
| Direction | PDO Object | Typical Mapping |
|---|---|---|
| RxPDO (from master) | Controlword (0x6040) | 16-bit command |
| RxPDO | Target position (0x607A) | 32-bit position setpoint |
| TxPDO (from slave) | Statusword (0x6041) | 16-bit status |
| TxPDO | Actual position (0x6064) | 32-bit actual position |
After mapping, download the configuration to the gateway and restart it.
4. Download and Test
Compile the hardware configuration in TIA Portal and download it to the S7-1200. Go online and check the gateway’s diagnostic status—it should show “Running” with no errors. Use a watch table to toggle control bits and monitor feedback. For example, write 0x0006 to the control word to enable the drive, then set a target position and observe the actual position changing.
Troubleshooting Common Issues
| Symptom | Possible Cause | Solution |
|---|---|---|
| Gateway not found by PLC | Device name or IP mismatch | Check name and IP in TIA Portal vs. gateway configuration tool |
| Servo not responding | EtherCAT slave not in OP state | Verify wiring, slave configuration, and PDO mapping |
| Incorrect position values | Scaling or byte order mismatch | Check encoder resolution and data type (big/little endian) |
| Communication loss | EMC interference or cable fault | Use shielded cables, proper grounding, and check connectors |
Benefits and Application Areas
This integration method preserves the existing PLC investment while leveraging high-performance EtherCAT servos. It is ideal for retrofits and new machines in packaging, lithium battery manufacturing, 3C electronics assembly, and other motion-intensive industries. The gateway handles protocol conversion with minimal latency, typically adding less than 1 ms to the control cycle.
Key Advantages:
- No need to replace the PLC or learn a new programming environment.
- Transparent data exchange: Profinet I/O directly maps to EtherCAT PDOs.
- Supports standard CiA 402 drive profile for interoperability.
- Scalable to multiple axes by daisy-chaining EtherCAT drives.
With careful configuration, the Siemens S7-1200 can control Inovance EtherCAT servos as if they were native Profinet devices, opening up a wide range of possibilities for machine builders and system integrators.
