B-Line 55 Series Photoelectric Sensor

It will not detect anything by itself. The 1256A-6502 is a through-beam device, so a complete system needs one source and one detector ordered separately, mounted facing each other across the gap you are monitoring. Budget for both units when you spec the job.

Only a small one. Output is L1 switched with a rating of 50 mA at 264 Vac, which is the ceiling on AC current draw through the sensor. That is enough for a small control relay or PLC input, not for a motor starter coil or anything pulling more than 50 mA inrush. Put an interposing relay in between if the load is larger.

Its environmental rating covers NEMA 1, 3, 4, 6, 12 and 13, which takes in rain-tight, watertight and hosedown duty as well as dust and oil in a plant. Operating temperature runs from -22 to 158 F (-30 to 70 C), so it holds up in unheated warehouses and near heat-producing equipment. Body is Noryl with a nylon lens.

Minimum object size is 0.4 by 0.7 inches (10 by 18 mm). Anything smaller than that will not break enough of the beam to trigger the output, so for small parts counting on a conveyor you need a different sensing approach.

It terminates in a 3-pin mini connector, so you mate it to a matching 3-pin mini cordset rather than landing conductors in a box. Order the cordset separately at the length you need. The sensor also has reverse polarity protection built in.

Through-beam, which is what the 55 Series 1256A-6502 is, puts the emitter and receiver on opposite sides of the opening. It gives the longest range and the most reliable detection through dust, mist or on shiny and dark targets, because the beam only has to travel one way. The trade-off is two mounting points and two cable runs. A retroreflective or diffuse sensor mounts on one side only, which is easier to install where you cannot get power or conduit to both sides, but it is more sensitive to contamination and to target surface.

There is a red LED on the unit showing output status. Watch it while you adjust the source and detector toward each other; a steady indication tells you the beam is made. That is the quickest alignment check on a mounting bracket at height.