Sensor identification and key ratings
The Omron E3SAR31 is a photoelectric proximity sensor from the E3S-A series, with a PNP output and a 2 m sensing distance in diffuse mode. Response time is rated 500 µs, suitable for moderate-speed object detection on conveyors or packaging lines. The red LED light source and light/dark switching give flexibility for background or foreground detection. Pre-wired cable and IP67 rating allow direct installation in wet or dusty environments without additional conduit sealing.
Comparing 2 m and 7 m E3S-A variants
The E3SAR31 (2 m) shares the same cylindrical housing, pre-wired termination, PNP output, and voltage range as the 7 m E3SAT81. The only functional difference is sensing distance: 2 m vs 7 m. For applications needing longer range, the E3SAT81 (or E3SAT31 with connector) is the alternative; if 2 m meets your target, the E3SAR31 drops in without wiring changes.
Wiring and integration note
PNP output: brown (10-30 VDC supply), blue (common), black (switched load). IP67 rating seals the pre-wired cable entry; avoid cutting the cable in wet zones.