Ethernet Module Integrates Schneider PLC for Packaging Machinery
In modern food and beverage production, automated filling lines demand high-speed, reliable data exchange between PLCs, SCADA systems, and HMIs. A common challenge arises when legacy RS485 serial communication cannot keep pace with growing data volumes and multi-device access. This article explores a real-world case where an Ethernet module transformed a Schneider TM218LFAE40DRPHN PLC-based packaging system, eliminating bottlenecks and enabling Industry 4.0 connectivity.
Project Background and Pain Points
A beverage manufacturer relied on a Schneider TM218LFAE40DRPHN PLC to control a high-speed filling line. The original setup used RS485 serial links to connect an upper computer (SCADA) and a Weintek HMI. As production scaled, several critical issues emerged:
RS485 maxed out at 115.2 kbps. Transmitting 128 analog values (temperature, pressure, flow) took over 80 ms per frame, causing noticeable lag on the SCADA screen. Operators couldn’t react promptly to process anomalies.
Modbus RTU allows only one master at a time. When SCADA polled data, HMI commands were blocked. This delayed parameter adjustments, increasing filling deviation by 0.5% and daily waste by 0.3%.
Electromagnetic interference from VFDs and motors caused RS485 faults twice a month. Each incident required 2 hours of downtime for termination resistor checks. Annual maintenance exceeded $15,000. Adding new devices meant laying new cables, taking 3 days.
Serial data couldn’t directly enter the plant Ethernet. Filling data was manually exported and imported into MES, delaying production reports by 4 hours. Management couldn’t adjust schedules in real time.
Solution Implementation
The plant integrated an industrial Ethernet module (similar to a Modbus TCP to RTU converter) to build a high-speed network. Here’s how it was done:
Hardware Connection
- PLC Side: Connected the TM218’s RS485 port (X8 terminal) to the module’s COM1 using shielded twisted pair. Settings: 115200 bps, 8 data bits, even parity, 1 stop bit.
- Network Architecture: The module’s RJ45 port linked to a gigabit switch on the plant LAN. The SCADA server (Dell) and Weintek MT8102iE HMI connected to the same switch, forming a star topology.
- Isolation: Built-in magnetic isolation suppressed ±2500V surges, ensuring stable communication even during motor starts.
Software Configuration
Module Initialization: Accessed the module’s web interface at default IP (192.168.1.178) and configured:
- Enabled Modbus TCP server on port 502
- Set static IP 192.168.1.100, subnet mask 255.255.255.0
- Mapped PLC data: %MW0-%MW255 to Holding Registers 40001-40256, %Q0.0-%Q15.7 to Coils 00001-00128
SCADA Configuration: In WinCC, added Modbus TCP driver, entered module IP and port, and linked to registers 40001-40256. C scripts enabled filling curve display and alarm thresholds.
HMI Programming: In EBPro, selected “Schneider Modbus TCP” protocol, configured IP and register mapping to display %MW10 (fill volume setpoint) and control %Q0.0 (fill valve).
PLC Program Adjustment: In SoMachine V4.3, replaced serial communication blocks with Modbus TCP client instructions, using function code 0x17 for read/write operations, ensuring seamless logic integration.
System Commissioning and Testing
Functional Verification:
- Simultaneous HMI speed change (%MW20) and SCADA historical query: response time under 20 ms, no data loss.
- With three 55 kW VFDs running, 72-hour continuous test showed bit error rate below 0.001%.
Performance Optimization:
- Enabled data caching: stores up to 1000 records during network interruption, bulk uploads upon reconnection.
- Configured SNMP for real-time communication monitoring via built-in web server, reducing fault location time to under 5 minutes.
Key Product Features
Supports up to 6 masters simultaneously. SCADA bulk polling and HMI operations coexist with <10 ms response, eliminating single-master conflicts.
Automatic Modbus RTU to TCP conversion without PLC code changes. Compatible with VB, C#, and custom monitoring software.
Wide temperature range (-40°C to 75°C), watchdog timer for auto-restart, remote firmware upgrades. Annual failure rate below 0.5 times.
New devices connect via switch and web configuration in 2 hours. System supports up to 32 devices.
Application Results Comparison
| Parameter | Before (RS485) | After (Ethernet Module) |
|---|---|---|
| Communication Speed | 115.2 kbps | 100 Mbps |
| Data Refresh Cycle (128 analogs) | >80 ms | <10 ms |
| Multi-Master Support | No (single master) | Yes (up to 6 masters) |
| Monthly Communication Faults | 2 | 0 |
| New Device Integration Time | 3 days | 2 hours |
| Annual Maintenance Cost | >$15,000 | <$2,000 |
| MES Data Delay | 4 hours | Real-time |
Conclusion
By deploying an Ethernet module as a serial-to-Ethernet gateway, the Schneider TM218LFAE40DRPHN PLC gained high-speed, multi-master Modbus TCP communication. This upgrade resolved speed limitations, improved noise immunity, and enabled seamless IT/OT integration. For packaging machinery in food, beverage, and pharmaceutical industries, such an architecture provides a scalable, future-proof foundation for smart manufacturing and Industry 4.0 initiatives.
Key takeaways for control engineers: when upgrading legacy RS485 networks, consider Ethernet modules that offer protocol conversion, web-based configuration, and industrial hardening. The result is reduced downtime, lower maintenance costs, and real-time data visibility across the enterprise.
Frequently Asked Questions
Q: Can any Ethernet module work with Schneider TM218 PLCs?
A: The module must support Modbus RTU on the serial side and Modbus TCP on the Ethernet side. Ensure it can handle the PLC’s specific register mapping and baud rate. Industrial-grade modules with isolation and wide temperature ranges are recommended for harsh environments.
Q: How do I configure the PLC program for Modbus TCP?
A: In SoMachine or EcoStruxure Machine Expert, use Modbus TCP client function blocks. Map the PLC’s memory areas to Modbus addresses as defined in the Ethernet module. No changes are needed if the module performs transparent protocol conversion.
Q: What are the benefits of using Ethernet over RS485 in packaging lines?
A: Ethernet offers higher speed (100 Mbps vs. 115.2 kbps), multi-master capability, easier integration with IT systems, and better noise immunity. It also simplifies wiring and allows remote diagnostics.
