Anonymous Manufacturer | Milan, Ohio
Executive Summary
A manufacturing facility in Milan, Ohio engaged PowerSafe Automation to modernize machine guarding on a production line where frequent access was required, but stored energy and long rundown times were not present. The existing mechanical interlock switches suffered from misalignment, nuisance faults, and evidence of bypassing—creating inconsistent safety performance and unnecessary downtime.
PowerSafe Automation engineered a guarding upgrade using Allen-Bradley SensaGuard non-locking RFID safety switches. The contactless RFID design delivered precise door-position monitoring, high tamper resistance, and reliable diagnostics—improving both safety integrity and operator efficiency without adding guard locking complexity.
Customer Background
- Industry: Advanced manufacturing and assembly
- Location: Milan
- Facility Type: Multi-station automated production line
- Guarding Style: Hinged and sliding access doors
- Primary Safety Need: Reliable door monitoring without guard locking
The customer requested anonymity due to internal safety governance but approved the project for anonymous case study use.
The Machine Safety Challenge
Application Overview
The guarded machines required:
- Frequent operator access for loading and inspection
- Short stop times with no residual hazardous energy
- Clear separation between access-open and run states
- Minimal interruption to cycle flow
Guard locking was not required for this application, but reliable access detection was critical.
Issues with Existing Interlocks
PowerSafe Automation’s on-site assessment identified several recurring problems:
- Mechanical tongue switches drifting out of alignment
- False trips from vibration and door wear
- Evidence of actuator defeat or bypass
- Limited diagnostic visibility for maintenance
Although the machines stopped when doors opened, the reliability of the detection method had become the risk.
Why Non-Locking RFID Safety Switches Were the Right Fit
Non-contact RFID safety interlocks are ideal when:
- Access must be monitored, not physically restricted
- Frequent door cycling is required
- Misalignment and wear are common failure modes
- Tamper resistance is a priority
Key Benefits of RFID Interlocks
- No mechanical contact or wear surfaces
- High tolerance for misalignment
- Unique-coded actuators reduce bypass risk
- Compact footprint for retrofit applications
For this project, Allen-Bradley SensaGuard switches provided the optimal balance of simplicity, robustness, and safety integrity.
Engineering the Safeguarding Solution
Step 1: Guarding & Access Review
PowerSafe Automation began with a guarding-focused engineering review, concentrating on:
- How often and why operators opened doors
- Door styles, travel, and mounting constraints
- Machine stop behavior and restart conditions
- Opportunities to eliminate nuisance trips
This ensured the selected technology matched actual use—not theoretical assumptions.
Step 2: RFID Interlock Selection & Placement
SensaGuard RFID switches were selected and installed to:
- Monitor each access door independently
- Maintain reliable detection despite vibration
- Reduce alignment sensitivity during door movement
- Provide clear, status-based feedback
Actuators were mounted to minimize the chance of defeat while remaining serviceable.
Step 3: Safety Circuit Integration
The RFID switches were integrated into the existing safety circuit to:
- Interrupt hazardous motion immediately upon door opening
- Prevent restart until all doors were closed and reset
- Provide diagnostic feedback for faults or misalignment
- Maintain separation between safety and standard controls
The architecture preserved fail-safe behavior without adding unnecessary complexity.
Installation & Commissioning
Mechanical Integration
- Compact switches mounted directly to guard frames
- No need for precision alignment tooling
- Retrofit completed without modifying guard structures
- Clean installation suitable for washdown-adjacent areas
Electrical & Controls Work
- Dual-channel safety outputs wired into the safety relay
- Door status tied to machine HMI indicators
- Reset stations verified outside hazard zones
- Functional tests completed for each access point
Installation was completed during a scheduled changeover window to avoid production disruption.
Operator Experience & Acceptance
Day-to-Day Usability
From an operator perspective, the upgrade was seamless:
- Doors opened and closed freely
- No “finicky” switch behavior
- Immediate and predictable machine response
- Fewer unexplained faults
Operators quickly gained confidence that the guarding system would respond consistently every time.
Training & Awareness
PowerSafe Automation provided focused training covering:
- How RFID interlocks differ from mechanical switches
- Why bypass resistance matters
- What diagnostic indicators mean
- Proper response to door-related faults
This improved both operator compliance and maintenance response time.
Results & Measurable Outcomes
Safety Improvements
- Reliable detection of all guard door openings
- Reduced opportunity for switch defeat
- Consistent enforcement of safe stop conditions
Operational Benefits
- Significant reduction in nuisance trips
- Faster recovery after door access
- Improved machine uptime
- More predictable operator workflows
Maintenance & Reliability
- Minimal wear-related maintenance
- Improved troubleshooting with diagnostics
- Longer service life compared to mechanical switches
Risk Reduction & Inspection Readiness
This project emphasized engineered reliability as a form of risk reduction:
- Contactless detection removed common failure points
- Unique-coded RFID reduced bypass potential
- Clear safety logic simplified inspection discussions
- Consistent door monitoring improved audit confidence
The result was a guarding system that worked as intended—day after day.
Why Allen-Bradley SensaGuard Non-Locking Switches Worked
Key Capabilities
- Compact, durable industrial design
- High tolerance to misalignment
- Strong resistance to tampering
- Clear diagnostic feedback
For applications without rundown hazards, non-locking RFID interlocks deliver effective, low-friction safeguarding.
Standardization & Future Expansion
Following the success of this project, the customer now has a standardized approach for:
- Guard door monitoring on similar machines
- Retrofitting legacy equipment
- New machine specifications
- Reducing spare part variety
This consistency supports long-term safety and operational efficiency.
Key Takeaways
- Guard locking is not always required—but reliable monitoring is
- Mechanical interlocks are a common source of nuisance faults
- RFID safety switches improve both safety and uptime
- Simpler systems often deliver better real-world performance
Conclusion
This anonymous manufacturer in Milan, Ohio successfully improved machine guarding reliability by upgrading to Allen-Bradley SensaGuard non-locking RFID safety switches.
By eliminating mechanical wear points, reducing bypass opportunities, and improving diagnostic clarity, PowerSafe Automation delivered a safeguarding solution that enhanced safety, improved uptime, and supported scalable machine safety standards—without adding unnecessary complexity.
