ZQ 700-11 - 3-Contact Redundant Interlock - SS IP67 Heavy Machinery Safety Switch

1. Product Overview​

The Schmersal ZQ 700-11 is an advanced electromechanical safety switch engineered for maximum security guard monitoring in hazardous industrial environments. Featuring a ​robust zinc die-cast housing (IP67 rated)​, this device utilizes a ​patented multi-pin coded actuator system​ to prevent defeat attempts through manipulation or forced entry. The "11" suffix denotes ​manual reset functionality, requiring deliberate key operation after guard closure to restart machinery. Certified to ​ISO 13849-1 PL e (Category 4)​​ and ​IEC 62061 SIL 3, it employs ​force-guided positively driven contacts​ that guarantee safe-state switching during component failures. Designed for extreme conditions (-25°C to +85°C), its corrosion-resistant construction withstands oils, coolants, and mechanical impacts. Integrated tri-color LEDs provide visual status for guard position, diagnostics, and reset requirements, while the unique 8-pin key system ensures only authorized personnel can reset the safety circuit.

​2. Key Technical Parameters​

• ​Safety Ratings:
  • PL e (ISO 13849-1 Cat. 4, DCavg=99%)
  • SIL 3 (IEC 62061, PFHD: 2.9×10⁻⁹/h)
  • ATEX Zone 22
• ​Electrical Specifications:
  • Voltage: 24V DC ±10% (19.2-28.8V)
  • Contacts: 2 NC + 2 NO (force-guided)
  • Current Rating: 6A @ 250V AC / 8A @ 24V DC
• ​Mechanical:
  • Actuator: 8-pin security key (1,024 combinations)
  • Switching Angle: 15° ±1°
  • Reset Torque: 0.6-1.2 Nm
• ​Environmental:
  • IP67 (IEC 60529)
  • Shock Resistance: 100g (IEC 60068-2-27)
  • Chemical Resistance: Resists oils, solvents, UV
• ​Diagnostics:
  • LED Indicators: Green (safe), Yellow (fault), Red (guard open)
  • Auxiliary NO contact for PLC diagnostics
• ​Certifications:
  • UL 508, CSA C22.2 No. 14
  • IECEx Ex tb IIIC T85°C Db

​3. Primary Applications​

This switch is critical for high-risk machinery requiring controlled restart:

• ​Robotic Workcells: Prevents restart until operators exit hazardous zones
• ​Metal Stamping Presses: Ensures dies are secured before cycle initiation
• ​Plastic Injection Molding: Mold area access with reset key accountability
• ​Automotive Paint Shops: Solvent vapor area guard monitoring
• ​Chemical Reactors: Mandatory reset after maintenance interventions
• ​Power Presses: Two-hand control system integration
• ​Pharmaceutical Isolators: GMP-compliant access control
• ​Foundry Equipment: Molten metal handling area security
  Its manual reset function is essential for applications where unauthorized restart could cause catastrophic accidents, particularly in maintenance-intensive environments with multiple technicians.

​4. Functional Advantages​

• ​Tamper-Proof Security:
  • Unique 8-pin key system (1,024 combinations)
  • Magnetic field detection defeats external bypass attempts
• ​Diagnostic Intelligence:
  • Tri-color LED status visible at 15m
  • Separate contacts signal welding/fault conditions
• ​Safety Assurance:
  • Positively driven contacts (EN 50205 certified)
  • Cross-monitored channels detect discrepancies >3ms
• ​Durability Features:
  • Hardened stainless steel key mechanism
  • Gold-plated bifurcated contacts
• ​Operational Control:
  • Key-retention feature prevents removal until guard closed
  • Audible reset confirmation click
• ​Maintenance Optimization:
  • Tool-free contact block replacement

  2 million mechanical cycles

• ​Compliance Ready:
  • Pre-validated templates for ANSI B11.19
  • SIL 3 integration with Schmersal SRB relays

​5. Safety Operation & Architecture​

​Guard Monitoring Sequence:

1. ​Guard Closure:
   • Coded key engages actuator cam
   • NC contacts close (machine remains stopped)
2. ​Manual Reset:
   • Key turn (30° rotation) validates guard position
   • Reset mechanism releases safety outputs
3. ​Continuous Monitoring:
   • Dual processors cross-check contact states
   • Timing discrepancies >5ms trigger shutdown
4. ​Fault Management:
   • Contact welding forces NO contact open
   • Yellow LED flashes during faults

​Safety Mechanisms:

• ​Mechanical Coding:
  • 8 spring-loaded pins require exact key alignment
  • Prevents picking/shimming attacks
• ​Reset Security:
  • Key cannot be removed in intermediate positions
  • Torque limiter prevents forced rotation
• ​Electrical Protection:
  • Redundant contact separation ≥0.8mm
  • Undervoltage lockout below 18V DC

​Diagnostic Hierarchy: