Why do some standard inductive proximity sensors have two wires instead of the usual three or four?
Answered by: Shane Jaconelli, RS components
The advantage of only having two wires is a reduction in:
• the number of wires needed
• the number of terminals needed in the connector
• the time taken to wire the device, and
• the current consumption of the device.
This is because the device is loop-powered, so doesn’t need a separate supply wire from the power supply.