Limit Switch: Key Position Guard In Industrial Automation

(MENAFN- GetNews) A limit switch , also known as a travel switch or position switch, is a control element that switches a circuit on and off through mechanical collision. In the field of industrial automation, limit switches play a vital role. Their core function is to detect whether an object has reached a predetermined position and convert mechanical displacement signals into electrical signals, thereby triggering equipment start/stop, steering, or safety protection actions.

Working principle and technical characteristics

The limit switchrelies on the external iron block or moving parts to hit its operating head (such as rollers, levers, etc.) to drive the internal Micro Switch to complete the contact switching. It has high action accuracy and strong anti-interference ability, and is suitable for all kinds of harsh environments. According to structural differences, the limit switch can be divided into direct-acting, roller-type, bidirectional composite type and other types to meet the collision direction requirements of different installation scenarios. The contact structure of the limit switch is usually normally open (NO) or normally closed (NC) design, which is convenient for seamless connection with control systems such as PLC and relays.

Core application scenarios

1. Mechanical equipment limit protection

In machine tools, cranes, and automated production lines, limit switches are widely used to limit the travel range of moving parts. For example, when the robot arm moves to the limit position, the limit switch is triggered and the motor power is immediately cut off to prevent the equipment from being damaged by impact.

2. Movement direction control

In scenes such as elevators and conveyor belts, travel switches can achieve precise positioning of reciprocating motion. When the elevator reaches a floor, the limit switch is triggered, and the control system switches the running direction according to the signal.

3. Safety interlock device

Limit switches are often installed on safety protection doors and equipment inspection openings to ensure that the equipment cannot be started when the door is not closed, thereby ensuring personnel safety.

Selection and maintenance points

When installing the limit switch, you need to consider the collision force, frequency and ambient temperature. Sealed limit switches can be selected in dusty environments, and heat-resistant materials should be used in high-temperature scenarios. Daily maintenance requires regular inspection of contact oxidation to avoid signal failure due to dust accumulation.

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