Through-beam set with 20 m reach
The Omron E3FB-TN21 is a complete through-beam photoelectric sensor set – transmitter and receiver in one order code – with a 20 m sensing distance through opaque objects as small as 7 mm diameter. The M18 threaded brass body and right-angle face orientation suit tight panel layouts and washdown zones. Power it from 10–30 V DC; the NPN sinking output switches up to 100 mA with a 0.5 ms response.
Connector vs prewired cable
Compared to the sibling E3FB-TN112M (same through-beam, NPN, 20 m), the E3FB-TN21 trades a 2 m prewired cable for an M12 4-pin connector. Both carry identical electrical ratings and IP protection. The connector version simplifies replacement – unplug the old sensor instead of cutting and re-terminating cable – and standardizes on the same M12 breakout your panel may already use for other sensors.
Output circuit: NPN vs PNP
If your PLC input module is sinking (NPN), the E3FB-TN21 fits directly. For sourcing (PNP), order the E3FB-TP21 instead – same M12 connector, same 20 m range, same IP67/IP69K, but PNP output. Confirm your input circuit before specifying.
Mounting and wiring in the panel
The M18 threaded body mounts through an 18 mm hole with a right-angle face. The M12 4-pin connector and selectable Light On/Dark On switch simplify installation; rated IP67 and IP69K.