The SEC 3120 Dual transmitter is designed to interface with two sensors and can be used with the SEC 5000
IREvolution®, SEC Millenium®, SEC Signature® infrared gas sensors or SEC 3000 and SEC 3300 toxic gas
detectors. The SEC 3120 is a multi-microprocessor based intelligent transmitter continuously monitoring
information from the gas sensor(s).

The LCD of the SEC 3120 displays the gas concentration and sensor status(s). The SEC3120 has one (1) “Alarm” LED and one (1) “Status” LED. The SEC 3120 also has three (3) magnetic switches located around the circumference of the unit. This manual will describe the operation and use of the SEC 3120 transmitter.