In industrial automation, interlocking devices are essential components for ensuring machine safety and protecting operators. Choosing the right technology is not just a technical decision, but a strategic one that impacts productivity, maintenance, and regulatory compliance.
In this guide, we compare electromechanical, electronic, and wireless interlocking devices, analysing their key features, limitations, and typical use cases.
What is an interlocking device?
An interlocking device is a safety component designed to control access to hazardous machine areas based on the machine’s operating state. It can prevent a machine from starting if a guard is open, or stop a guard from being opened during a cycle.
These devices are essential to meet standards such as the Machinery Directive, ISO 14119, and ISO 13849, and to determine the Performance Level (PL) of a safety system.
Electromechanical Interlocks: robust and reliable
Electromechanical devices are based on physical contacts, latches and micro-switches. They are widely used thanks to their mechanical simplicity and proven reliability.
Advantages
- Simple design and reliable operation
- Cost-effective
- Suitable for standard industrial environments
Limitations
- Mechanical wear over time
- Sensitive to dust, chips, and moisture
- Larger footprint compared to modern alternatives
Applications
- Lathes, presses, traditional machine tools
- Hinged or sliding guards
- Areas with moderate risk and low access frequency
Electronic Interlocks: high-performance and intelligent
Electronic interlocks use RFID, coded systems or digital sensors to provide secure and traceable control.
Advantages
- High reliability and support for PL/SIL ratings
- Difficult to bypass
- No mechanical wear
- Integrated diagnostics via PLC protocols (e.g., IO-Link, Ethernet)
Limitations
- Higher cost
- Software integration required
- Dependent on stable power supply
Applications
- Automated production lines
- CNC machines, packaging and robotic systems
- Zones requiring frequent access and detailed diagnostics
Wireless Interlocks: flexibility for modular systems
Wireless interlocks are ideal for mobile or modular machines, where traditional cabling is impractical.
Advantages
- No wiring → fast and flexible setup
- Perfect for robotic arms or rotating machinery
- Great for retrofitting existing equipment
Limitations
- Higher initial investment
- Battery or energy harvesting required
- Potential RF interference in some environments
Applications
- Mobile guards and rotating tables
- Modular production units
- Scenarios with complex cable routing
How to choose the right interlocking device
There’s no universal solution. Selection depends on:
- Required risk level (Performance Level)
- Frequency of operator access
- Type of motion to be restricted
- Environmental conditions (dust, humidity, vibrations)
- Compatibility with control systems
- Installation and maintenance constraints
TSA Padova: your partner for industrial safety
With over 45 years of experience in industrial safety, TSA Padova helps companies choose the best interlocking solutions.
We assist:
- System integrators and machine designers
- HSE managers and safety officers
- Workshops and companies modernizing production lines
Our offer includes:
- A wide portfolio of mechanical, electronic and wireless interlocks
- Technical consulting for selection and sizing
- After-sales support and system integration
Contact TSA Padova for expert advice on selecting the right safety devices for your machines. Safer choices today mean fewer risks tomorrow.
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