Limit switch

How it is used

Used to detect end positions, door positions and overtravel. It has an actuator such as a roller lever or a plunger, and normally open (NO) or normally closed (NC) contacts. In motion systems, hardware limit switches back up the software limits.

Example sentences

1. The carriage hit the limit switch and the axis stopped with an overtravel alarm.

2. Replace the roller on the limit switch; it's completely worn.

Common collocations

• end-of-travel limit switch
• hit the limit switch
• roller lever
• overtravel limit

Related terms

• proximity sensorA sensor that detects an object near it without touching it. Inductive types detect metal; capacitive types also detect plastic, wood or liquids.
• sensorA device that detects a physical quantity or an event, such as position, distance, force, temperature or the presence of a part, and turns it into a signal a controller can read.
• I/OShort for inputs and outputs: the signals a controller receives from sensors and buttons, and the signals it sends to valves, motors, lamps and other devices.
• interlockA safety or control function that prevents a machine from running unless certain conditions are met, for example a door switch that stops the robot when the guard door opens.
• axisOne controlled direction of motion, either a rotation or a straight-line movement, driven by its own motor. Also a line in a coordinate system, such as the X, Y or Z axis.

More terms: Sensors, Motors and Actuators

• actuator
• servo motor
• encoder
• pneumatic cylinder
• stepper motor
• photoelectric sensor
• solenoid valve
• variable frequency drive