Industrial Automation — Cylinder & Machine Position Detection

- Nov 9, 2026-

Reed proximity switches are the workhorse of factory automation. They detect position without contact, need no standby power, survive dust and oil, and cost very little, which is why they remain the most widely used sensor for pneumatic cylinders and machine position detection even after decades of service.

Pneumatic and Hydraulic Cylinder Position

A magnet is built into the cylinder piston, and a reed switch is mounted on the outside of the cylinder barrel. When the piston reaches the end of its stroke, the magnet triggers the switch and signals the controller that the position has been reached. This is the highest-volume reed switch application in industry. Lifetimes exceed ten million operations, the switches work on AC or DC, draw no standby power, and cost far less than electronic alternatives. In very high-speed applications the response is slightly slower than a Hall sensor, and strong vibration can cause contact bounce, so the choice depends on the machine.

Conveyor and Machine Position / Limit Switching

Reed proximity switches detect material arriving on a conveyor, the end of travel of a robot arm, and the open or closed state of safety guards and protective covers. They are sealed and tolerant of dust and oil, which suits harsh workshop environments. They also serve as safety interlocks: if a guard is opened, the machine stops. Their simplicity and reliability make them a standard choice for position and limit detection across production lines.

Industrial Flow Monitoring

Reed flow switches monitor liquid flow in industrial pipework, cooling circuits, and lubrication systems, raising an alarm or shutting down equipment when flow falls below the safe level. A paddle or piston in the flow path moves a magnet toward a reed switch as flow rises, on the same principle as the flow switches used in data center cooling, adapted to different media and pipe sizes. Flow monitoring protects pumps, bearings, and process equipment from damage caused by loss of coolant or lubricant.

Why Reed and Level Sensing

Reed proximity switches are sealed in glass, so dust, oil, and moisture cannot reach the contacts. They switch without contact and without wear at the sensing point, they need no power to hold a state, and they are inexpensive enough to fit everywhere a position needs to be known. For machine builders, they are the proven, low-risk choice.