The AOI Series 3500 is a loop-powered trace oxygen transmitter designed to provide reliable oxygen measurements in a variety of background gases. Housed in a durable NEMA 4X (IP66) watertight polycarbonate enclosure, it is well-suited for demanding industrial environments. The 4-20 mADC output can be directly interfaced with data loggers, recorders, PLCs, or digital control systems .

The Series 3500 features an ambient-temperature electrochemical sensor. Its enhanced mechanical design ensures longer life and virtually eliminates leakage of caustic electrolyte. The sealed sensor is not position-sensitive and does not require manual adjustment based on changes in the molecular weights of sample gases like helium and hydrogen. The output from the sensor is both linear and temperature-compensated to provide optimum performance. An optional CO2-tolerant trace oxygen sensor is capable of providing accurate oxygen readings in gases containing up to 100% CO2 without shortening the sensor's life .

Key specifications include a wide selection of eight measurement ranges, from 0-10 ppm up to 0-20,000 ppm, covering a broad spectrum of trace oxygen applications. It offers ±1% of full scale accuracy and a fast 90% of full scale response time of less than 10 seconds. The transmitter operates on a 14-32 VDC input power, making it easy to integrate into existing loop-powered systems. The electronics carry a 2-year warranty, and the sensor carries a 1-year warranty .