A position sensor is a sensor that detects the position of an object and converts it into a usable output signal.
Position sensors can be used to detect position and reflect a certain state of a switch. Unlike displacement sensors, position sensors can be divided into two types: contact sensors and proximity sensors.
1. Contact sensor
Contact sensors operate by the contact and pressure of two objects. Common examples include limit switches and two-dimensional matrix position sensors. Limit switches are simple in structure, reliable in operation, and inexpensive. When an object moves and encounters a limit switch, its internal contacts activate, thus controlling the movement. For example, installing limit switches at both ends of the X, Y, and Z axes of a machining center allows for control of the movement range. Two-dimensional matrix position sensors are installed inside the palm of a robotic arm to detect the contact position between the arm and an object.
2. Proximity sensor
A proximity switch is a switch that emits an "action" signal when an object approaches within a set distance, without requiring direct contact with the object. There are many types of proximity switches, mainly including electromagnetic, photoelectric, differential transformer, eddy current, capacitive, reed switch, and Hall effect switches. In CNC machine tools, proximity switches are primarily used for tool selection control, table travel control, and piston travel control for hydraulic and pneumatic cylinders.
