TESK-LA-11ST1 Mechanical Interlock Safety Switch IP67 Stainless Steel Machine Guard Lock

1. Product Overview

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The Schmersal TESK-LA-11ST1 represents a high-security interlock safety switch specifically engineered for applications requiring controlled access to hazardous machinery through hinged or sliding guards. This device integrates robust guard door monitoring with ​electromagnetic locking (solenoid)​​ functionality, ensuring the guard remains securely locked until the machine reaches a safe state. Constructed with a rugged ​zinc die-cast housing, it achieves an ​IP67 protection rating​ for reliable operation in harsh industrial environments like metalworking, automotive, or dusty manufacturing plants. The switch incorporates two fundamental elements: an actuator head mounted on the guard door and a body unit fixed to the machine frame. Activation occurs via a high-precision ​6-pin high-security coded magnet cylinder (Type G)​​ within the actuator, providing unmatched resistance to tampering and defeating. Its defining feature is the integrated solenoid which requires a deliberate electrical signal (power-to-unlock principle) to release the locking mechanism, creating a highly secure access control system that prevents unauthorized or premature opening during machine operation.

​2. Key Technical Parameters

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The TESK-LA-11ST1 operates with a standard ​control voltage of 24V DC (±10%)​, specifically designed for integration into industrial safety circuits. Its robust solenoid lock generates an impressive ​holding force of 500 N, effectively securing the guard door against accidental or forced opening. The switch includes two critical signal channels: ​Force-Guided Relays (FGR)​​ configured as 1 NC (Safety) + 1 NO (Monitoring/Auxiliary) contacts, rated for ​6A @ 250V AC / 10A @ 24V DC. Safety certifications are paramount, achieving ​Safety Integrity Level SIL 3 (IEC 62061)​​ and ​Performance Level PL e (ISO 13849-1, Category 4)​​ for use in the highest-risk safety circuits. Environmental specifications include an operating temperature range of ​​-25°C to +70°C, immunity to high vibration, and resistance to oils and coolants. Additional features include high visibility ​LED status indicators​ for power, lock status, and switch position, an ​automatic short-circuit monitoring​ loop (test pulse monitoring), and the critically important guard locking functionality classified under ​EN ISO 14119 as Type 4 (high safety) with Power-to-Unlock principle. Mechanical endurance exceeds ​1 million operating cycles.

​3. Primary Applications and Use Cases

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The TESK-LA-11ST1 is indispensable in scenarios where safeguarding personnel demands not only monitoring guard door position but actively preventing access while danger exists. Key deployments include ​industrial robots, heavy presses, injection molding machines, automated assembly lines, and CNC machining centers, where the machine cycle must complete safely before access is permitted. Its high holding force and tamper-resistant coding make it ideal for protecting high-energy hazards involving crushing, shearing, cutting, or rapid movement. Specific applications include safeguarding maintenance enclosures on automation cells, access hatches to robotic welding stations, loading doors on stamping presses, and service points on palletizing systems. It ensures that operators cannot access danger zones during machine cycle execution and prevents restart until the guard is securely closed and locked again. Environments range from automotive manufacturing with paint fumes to foundries with significant dust and vibration.

​4. Product Advantages and Functional Benefits

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This safety switch delivers significant safety and operational advantages. Its ​electromagnetic locking (500 N force)​​ ensures the guard door stays locked during hazardous machine states, providing an active barrier against accidental or deliberate opening. The ​high-security magnetic coding (Type G)​​ offers exceptional resistance to defeating attempts compared to lower-grade switches. ​Standard IP67 protection​ guarantees reliable function despite dust, moisture, and washdown cleaning protocols. The ​integrated status LEDs​ provide clear, immediate visual feedback to operators about safety status and lock conditions. Its design enables compliance with the strictest standards (PL e, SIL 3, Cat 4) using a single compact device, simplifying safety circuit design and validation. ​Independent Force-Guided Relay channels​ provide high diagnostic coverage against dangerous failures like welded contacts. A key operational benefit is the ​power-to-unlock release, which prevents door opening until the safety PLC deliberately energizes the solenoid, ensuring access is only granted when the process is safe.

​5. Core Functionality and Safety Integration

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The TESK-LA-11ST1 operates through an integrated sequence combining position detection, locking, and controlled release. When the guard door closes, the high-security magnetic actuator (Type G) aligns with the body unit, changing the state of the ​Normally Closed (NC) safety contacts, signaling the safety PLC that the guard is securely closed. Simultaneously, the ​solenoid locking bolt engages, physically blocking the guard from opening. This locking bolt is not mechanically released when power is removed (essential fail-safe behavior). To unlock the guard safely, the machine must be in a confirmed safe state (zero energy, stopped). The safety PLC then deliberately sends ​24V DC power​ to the switch's solenoid. Only upon receiving this specific "safe-to-open" signal does the solenoid retract the bolt, allowing the door to be opened. Opening the door immediately opens the NC safety contacts, initiating a safety stop if not already achieved. Resetting requires re-closing the door and engaging the lock. This controlled ​Power-to-Unlock​ sequence is central to preventing access during hazard periods and ensures restart safety via positive locking and monitoring.

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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