The SM30 series opposed-mode Infrared Photoelectric Sensor for especially demanding applications. Modulation frequency “A” is standard, frequencies “B” and “C” also available for preventing crosstalk in multiple-sensor applications (emitter and opposed receiver frequencies must match). PVC-jacketed 2 or 9m cables or Mini-style quick-disconnect (QD) fitting are available. Internal red LED, visible through the lens or from side of the sensor. Outputs of DC receivers are short circuit protected. The device is protected against reverse polarity and transient voltages.