Through-beam photoelectric sensor, 3 m range, NPN output
The Autonics BYD3M-TDT is a through-beam photoelectric sensor from the BYD Series, offering a 3 m detecting range with a 12-24 VDC power supply and an NPN open collector output. The through-beam design means the emitter and receiver are separate housings — the beam is broken when an object passes between them, giving reliable detection over the full 3 m span without blind spots. This makes it a strong fit for conveyor gating, pallet presence, or part-in-place checks where the target is opaque and the mounting path is clear. The NPN output sinks current to ground, which is the standard logic for many Asian-origin PLC input cards and older DC control circuits.
Operation mode flexibility
The BYD3M-TDT ships in Dark ON mode by default, with Light ON available as a wiring option. Dark ON means the output activates when the light path is blocked — useful for detecting the presence of an object. Switching to Light ON reverses that logic, so the output is on when the beam is uninterrupted, which suits applications like edge detection or counting transparent objects. The selection is made at the wiring terminal, not via DIP switch, so the mode is fixed once the cable is landed.