T3C 235-11Z-M20 Mechanical Interlock Safety Switch IP67 Stainless Steel M20 Industrial Guard

1. Product Overview

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The Schmersal T3C 235-11Z-M20 is a rugged, tongue-operated safety limit switch engineered for precise interlocking applications in automated machinery and safety systems. This ​EN ISO 13849-1 and IEC 62061 certified​ device features a ​glass-fiber reinforced polyamide housing (IP67 rated)​​ that protects against dust, water jets, and mechanical impacts. Its distinctive T-shaped actuator tongue extends 48mm ("235" series) and requires controlled operator engagement with guided access. The "-M20" suffix denotes an integrated ​M12 male connector (coded to DIN EN 61076-2-101)​​ enabling tool-free plug connection, while "-11Z" indicates one normally open (NO) and one normally closed (NC) contact configuration using ​force-guided (EN) relays. Designed for guard locking, access control, and position verification, this switch provides reliable safety signaling for SIL 2/PL d applications. Its self-monitoring mechanical design ensures positive contact separation even during component failure.

​2. Key Technical Parameters​

• ​Actuator:​​ T-shaped tongue, 48mm length × 19mm width, ±2mm tolerance
• ​Operating Force:​​ 50-60N for actuation (adjustable spring characteristics)
• ​Electrical Rating:​​ 10A @ 250V AC (resistive), 5A @ 24V DC
• ​Safety Classification:​​
  • ​ISO 13849-1: PL d, Category 3​
  • ​IEC 62061: SIL 2 (HFT=0)​​
• ​Environmental Resistance:​​
  • IP67 protection (IP69K optional)
  • Temperature range: ​​-30°C to +85°C​
  • Impact resistance: 30J (IK08)
• ​Mechanical Life:​​ 1 million operations
• ​Response Time:​​ <15ms contact break
• ​Connection:​​ M12 × 1 male connector (A-coded), 4-pin
• ​Housing Material:​​ Polyamide (PA) + 30% glass fiber

​3. Primary Applications and Use Cases

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This switch is deployed where robust mechanical positioning and safety interlocking are critical. In ​robotic workcells, it monitors safety gate positions, triggering immediate shutdown when doors breach containment during operation. ​Packaging machinery​ utilizes it to confirm tooling alignment and guard engagement before initiating high-speed wrapping cycles. For ​automated assembly lines, it provides position feedback for indexing tables and rotary actuators. ​Material handling systems​ rely on it for verifying hoist limit positions and conveyor guard closures. Additional key applications include:

• Medical equipment sterilization chamber door interlocks
• Plastic injection molding machine safety gates
• Railway vehicle access panel monitoring
• CNC machine tool guard verification
• Food processing zone transition barriers
  Its compact design (68×80×40mm) makes it ideal for space-constrained installations, while the visible T-actuator provides clear engagement feedback to operators.

​4. Product Advantages and Functional Benefits​

• ​Fail-Safe Design:​​ Positive-break mechanism forcibly separates contacts during spring/actuator failure
• ​Enhanced Security:​​ T-shaped actuator requires guided access, defeating tampering attempts
• ​Corrosion Resistance:​​ Polyamide housing withstands aggressive coolants/cleaning agents
• ​Simplified Wiring:​​ M12 plug connection reduces installation time by 60% vs. terminal boxes
• ​Misalignment Tolerance:​​ ±5° angular acceptance compensates for mounting variations
• ​Diagnostic Capability:​​ Independent NO/NC contacts enable circuit self-monitoring
• ​Drop-In Replacement:​​ Compatible footprint with industry-standard safety switches
• ​Safety Compliance:​​ Meets EN 1088 and ANSI B11.19 standards for guard interlocks
• ​Maintenance Reduction:​​ Hermetically sealed contacts prevent dust ingress-related failures

​5. Core Functionality and Safety Operation

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The T3C 235-11Z-M20 operates through redundant safety principles. When the actuator tongue is depressed by a machine guard or moving part, it physically drives a cam mechanism that simultaneously:

1. Opens the ​NC safety circuit​ (disabling machine power)
2. Closes the ​NO auxiliary contact​ (providing position confirmation)
   Critically, both contacts are ​mechanically linked via force-guided relays​ – any failure that prevents NC contact opening simultaneously prevents NO contact closure. This creates a detectable fault state. Safety controllers monitor both signals; valid operation requires:

• ​Guarded position:​​ NC ​open​ & NO ​closed​
• ​Unguarded position:​​ NC ​closed​ & NO ​open​
  Deviation from these states triggers an immediate safety stop. The hardened tongue actuator withstands repeated impacts from slamming guards without deformation, while the IP67-rated M12 connector maintains signal integrity in humid environments. With an MTTFd (mean time to dangerous failure) >25 years, this switch provides Category 3 safety with >99% diagnostic coverage (DCavg) when integrated per Schmersal's safety guidelines.

Packaging & Shipping

Company Information
Xiamen ZhiCheng Automation Technology Co., Ltdit is a leading global supplier of control system components. We specialize in control systems and drives.

With many years of experience in the industrial sector, we consistently deliver the highest quality of spare parts.which make sure that all this jobs are

perfectly.

we are major in PLC,Sensors,HIM,Transmitters.

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