{"id":1674,"date":"2026-09-28T14:10:00","date_gmt":"2026-09-28T06:10:00","guid":{"rendered":"https:\/\/lemaele.com\/blog\/linear-actuator-limit-switch-guide\/"},"modified":"2026-09-28T14:10:00","modified_gmt":"2026-09-28T06:10:00","slug":"linear-actuator-limit-switch-guide","status":"publish","type":"post","link":"https:\/\/lemaele.com\/es\/blog\/linear-actuator-limit-switch-guide\/","title":{"rendered":"Interruptor de limitaci\u00f3n para actuadores lineales: control de final de recorrido"},"content":{"rendered":"

A limit switch for a linear actuator can mean an internal end-of-travel device built into the actuator, an external mechanical switch placed along its moving path, or a signal input to the actuator controller. These are not interchangeable. Start with the actuator’s own wiring diagram and operating limits, then decide what event must stop extension or retraction and how the controller will respond. A limit switch is a sensor and circuit element; it must not be treated as a mechanical hard stop or assumed to be a complete safety function.<\/p>\n

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LEMA LZ8 product-library original showing two miniature limit-switch actuator forms. The photo is a product example, not a claim that this switch is a pre-wired linear-actuator kit.<\/figcaption><\/figure>\n
\"LEMA
A distinct LZ8-series spring-rod product view. The target must match the chosen actuator head’s specified direction and travel.<\/figcaption><\/figure>\n

First decide whether the actuator already has travel limits<\/h2>\n

Read the exact actuator model documentation before adding a switch. Some linear actuators have built-in end switches, adjustable internal limits, encoder feedback or a controller that stops motion at configured positions. Others provide only motor power leads and expect the equipment designer to provide external control. The product name or stroke length alone does not tell you which arrangement is present.<\/p>\n

Draw the operating chain from the actuator to the machine controller. Identify which device senses the endpoint, what signal changes, which circuit interrupts or inhibits motion, and how the actuator is allowed to move in the opposite direction after reaching a limit. An internal end switch may open one motor direction while allowing reverse motion, or it may report state to a controller. An external switch may instead send a low-current input to a relay, PLC or motor driver. Confirm the actual diagram rather than applying a generic wiring pattern.<\/p>\n\n\n\n\n\n\n\n
Limit approach<\/th>\nWhat it does<\/th>\nWhat to verify<\/th>\n<\/tr>\n<\/thead>\n
Built-in actuator end switch<\/td>\nChanges state at a manufacturer-defined point within the actuator<\/td>\nWhether it interrupts motor current or signals a controller, and whether reverse travel remains available<\/td>\n<\/tr>\n
External mechanical limit switch<\/td>\nSenses a moving target or bracket at a chosen position<\/td>\nActuator geometry, switch rating, mounting stiffness, contact logic and permitted overtravel<\/td>\n<\/tr>\n
Controller position limit<\/td>\nUses an encoder, feedback sensor or controller configuration to stop commanded movement<\/td>\nFeedback type, configuration, fault response, braking\/coast and any independent overtravel protection<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Define the event the switch needs to detect<\/h2>\n

Write down the required event in machine terms: fully retracted, fully extended, a service position, a clamp reached its set point, or a moving assembly entered a restricted zone. If the required output is a repeatable position rather than a simple end signal, make sure a mechanical switch is the right sensor. A proximity sensor, encoder or actuator feedback input may suit the task better when there is no suitable physical target, when contact wear is unacceptable, or when the controller needs continuous position information.<\/p>\n

For a mechanical switch, check that the moving target reaches the actuator in the intended direction. An LZ8-series product view shows different actuator-head forms; the separate LEMA actuator-type reference<\/a> illustrates additional roller, plunger and rod arrangements. Choose from the actual path and target geometry, not from a familiar-looking photograph. Do not assume a roller lever, spring rod and plunger share the same operating point or permitted force.<\/p>\n

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Original LZ8 actuator-option drawing. It illustrates product-family head styles; confirm the exact ordered actuator and dimensions.<\/figcaption><\/figure>\n

Set the operating point without using the switch as a stop<\/h2>\n

Define the normal stopping position and the available margin beyond it. The actuator, linkage, bracket and machine all have tolerances. Add the actual movement after the controller receives a stop signal, including motor coast, load inertia, elastic deflection and control delay. If a position is safety-critical, determine the required stopping behavior from the machine-level risk assessment; do not infer it from the switch’s response time alone.<\/p>\n

OMRON’s technical guide<\/a> defines free position, operating position, release position, pretravel, total travel and overtravel as separate switch characteristics. In practical terms, the target must travel far enough to operate the contacts but must not drive the switch actuator past its permitted travel. Provide a physical machine stop or engineered travel restraint where required, so the switch head is not struck as the mechanical end stop. A switch that stays depressed continuously, receives a side load, or is hit at an angle can wear or fail early.<\/p>\n

For a roller lever, design the cam or target so it approaches and leaves smoothly. For a pin plunger, keep the motion aligned with the plunger. For a rod or spring-wire actuator, respect the specified force and direction. OMRON’s correct-use guidance<\/a> warns against exceeding overtravel and applying unbalanced force. Verify the exact LEMA model drawing and operating-characteristic data; do not scale dimensions from a web photo.<\/p>\n

Check the electrical interface before connecting the motor<\/h2>\n

An actuator motor can draw a high starting current and create inductive transients when interrupted. A miniature mechanical switch must not be connected directly in a motor circuit unless its specific rating, current type, load category and circuit arrangement permit that use. For many designs, the limit switch should signal a controller or operate a properly rated relay\/contactor, while the motor power stage handles drive current. The control approach depends on the actuator schematic; a relay, diode or suppression component can also affect reverse motion and release behavior.<\/p>\n

Record the supply voltage, AC or DC, motor running and starting current, number of travel directions, required contact form, controller input type and expected switching frequency. Check whether the design uses normally closed contacts to help detect an open wire, and whether the controller can distinguish a broken conductor from a reached limit. An NC contact is not automatically a fail-safe circuit: safety depends on the whole architecture and validated fault response.<\/p>\n

The video below introduces limit-switch and over-travel sensors in a servo-motion context. The Yaskawa training record<\/a> describes it as a short technical overview. It is useful background on end limits, but it does not describe a LEMA linear-actuator kit or replace the actuator manufacturer’s wiring information.<\/p>\n