3-Wire Sensors

3-wire sensors are sourcing, type "PNP", or sinking, type "NPN", with separate connections for the power supply and for the output. These sensors are protected against overload, short circuit, and reverse polarity. The residual current is negligible. For sensor type PNP, the load is connected between the output and ground potential (L-). For sensor type NPN, the load is connected between the output and L+.

3-Wire Sensor Versions

These sensors are usually marked with the following in the third block of the Pepperl+Fuchs order designation:

–E 

Sensors of type –E are available in the following switching element functions:

• NPN, normally-open (E0, formerly E)
• NPN, normally-closed (E1)
• PNP, normally-open (E2)