Interfacing Magnetic Proximity Sensors to PLCs

A demonstration of a reciprocating pneumatic cylinder using a Programmable Logic Controller and two magnetic proximity sensors.
We've done a number of sensor demos with simple electronics or single-board computers. But PLCs are popular, especially in harsh environments. They tolerate vibration, shock, and electrical noise better than PCs. And they can directly control line voltage or large DC loads like motors and valves.
PLCs need robust sensors, and AD-Series magnetic switch specifications are ideal for PLCs. And unlike other types of sensors, GMR sensors have in-plane magnetic sensitivity, so we don't have to stand a board on edge.
The two sensors set the two travel limits and there's a disk magnet on the piston.
We used a pneumatic cylinder, a three-position, five-port Directional Control Valve with exhaust center. With a three-position valve we could extend, retract, and stop the cylinder.
We showed the PLC ladder diagram, which was created using RSLogix 500 software.
More details on the sensors used for this demo here:
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