PLC Split Project: Resolving Safety Scan Time Limitations

Challenge

A global automotive OEM framing line was experiencing controller performance limitations caused by excessive Safety Scan Time within the existing Siemens S7-300 safety architecture.

Over time, the line accumulated additional robots, welding systems, safety devices, HMI functionality, and Profinet communications. This increasing complexity placed significant demand on the existing controller, causing periodic processor performance issues and creating a risk to production stability.

The customer required a solution that would eliminate controller overload conditions while maintaining production availability, safety compliance, and future scalability.

Solution

Tech Automation performed a detailed evaluation of the existing control architecture, including CPU loading, safety program execution, Profinet network infrastructure, shared signals, robot integration requirements, safety matrix validation, and HMI architecture.

Based on the analysis, Tech Automation engineered and implemented a PLC split strategy that divided the original framing line into two independent Siemens control domains.

The original controller retained responsibility for stations 135, 130, 120, 110, and 100, while a new Siemens S7-300 controller was deployed to manage stations 90, 80, 71, 70, and 60.

Project Scope

• PLC architecture redesign
• Signal migration and redistribution
• Safety matrix redesign and validation
• Profinet network modifications
• Scalance infrastructure expansion
• Additional HMI integration
• Hardware installation and commissioning
• Production startup support

Technologies

• Siemens S7-300 CPU 319F
• Siemens Profinet Networks
• Siemens Scalance Managed Switches
• Automotive Welding Systems
• Safety PLC Architecture
• Industrial HMI Systems
• Automotive Robotics Integration

Results

The new architecture successfully eliminated the Safety Scan Time limitations affecting the original controller while preserving production functionality and safety compliance.

Following implementation, the framing line achieved improved controller performance, increased system scalability, enhanced maintainability, and a stable foundation for future production requirements.

Key Benefits

• Eliminated controller overload conditions
• Resolved Safety Scan Time performance issues
• Improved production reliability
• Maintained safety compliance
• Increased future scalability
• Successfully commissioned with minimal production disruption

```