Lifeguard ® PO2 Sensors ‘Tee’ Tutorial © 2015 Cochran Consulting, Inc. Introduction PO2 Sensor Factors PO2 Sensor Tee Installation Cochran Consulting, Inc. 5 October 2015

Lifeguard ® PO2 Sensors ‘Tee’ Tutorial © 2015 Cochran Consulting, Inc. The Cochran Lifeguard Recorders and Lifeguard CPU Dive Computers are available in models that are compatible with external PO2 Sensors with positive or negative output PO2 sensors. The Lifeguard Recorders R3, R4, and R5 accept negative output sensors while the R6, R7, and R8 accept positive output sensors. The Lifeguard CPU Dive Computers C3, C4, and C5 accept negative output sensors while the C6, C7, and C8 accept positive output sensors. All of these models have a four conductor PO2 cable attached and the other end has a waterproof connector. One contact is common (ground) and the other three are inputs from the outputs of up to three PO2 sensors. This Lifeguard ‘Tee’ is designed to provide a negative voltage output and is compatible only with the R3, R4, R5, C3, C4, C5 Lifeguard models. It is intended to be used with a single PO2 Sensor “PSR NM”. Introduction

Lifeguard ® PO2 Sensors ‘Tee’ Tutorial © 2015 Cochran Consulting, Inc. The Lifeguard Recorders and Dive Computers that have PO2 Sensor capability all can accommodate up to three PO2 Sensors. When using the PO2 Sensor Tee, only one PO2 Sensor (PO2 Sensor ‘a’ ) is used, the other unused PO2 Sensors (PO2 Sensors ‘b’ and ‘c’) should be disabled via the Lifeguard Analyst 5 PC Software. This will prevent the system from flagging the unused PO2 Sensors as malfunctioning and issuing false warnings. See the Lifeguard Analyst 5 Tutorial for details on how to do this. The Lifeguard PO2 Sensor Tee does not provide any loading on the PO2 Sensor within the Tee. Any loading is provided internally to the attached Lifeguard module. Standard loading is 12k ohms, but custom loading values of 14k ohms or less is available. Contact Cochran for more details. All PO2 Sensor compatible Lifeguard modules have their Sensor Measuring subsystem calibrated at the factory to a high degree of accuracy and stability. This means that the user only needs to calibrate for changes in the PO2 Sensor itself. Furthermore, because the PO2 readings are not affected by changes in battery voltage, fewer field calibrations are required. In addition, there is a user-selectable option that allows the system to automatically compensate for altitude during field calibration. Important Factors

Lifeguard ® PO2 Sensors ‘Tee’ Tutorial © 2015 Cochran Consulting, Inc. PO2 Sensor and Tee Install Pictured is a close up of the completed assembly of the Tee, PO2 sensor, cap and cable inserted into the Inhalation Hose. The Tee is bidirectional and can be installed with the Cable pointing in either direction. The Tee has a large inside diameter and does not affect The breathing characteristics. The assembly inserted into the Inhalation hose showing the cable direction toward the rebreather unit hose attachment. It is critical that the Tee be installed in the INHALATION hose.

Lifeguard ® PO2 Sensors ‘Tee’ Tutorial © 2015 Cochran Consulting, Inc. Pictured is the tee, PO2 sensor and cap that includes the sensor connector and external connector. The PO2 sensor lead connector will be tucked under the wire tied part of the leads, as shown. PO2 Sensor and Tee Install

Lifeguard ® PO2 Sensors ‘Tee’ Tutorial © 2015 Cochran Consulting, Inc. Connect the PO2 sensor connector to the connector inside the cap. Turn the PO2 sensor over on top of the cap and align the connector with notches inside the cap. Lower the PO2 sensor onto the cap. PO2 Sensor and Tee Install

Lifeguard ® PO2 Sensors ‘Tee’ Tutorial © 2015 Cochran Consulting, Inc. Turn the cap and PO2 sensor assembly upright, making certain the sensor, cap and connector line up with each other. Wrap two turns of Teflon tape onto the threads of the cap. PO2 Sensor and Tee Install

Lifeguard ® PO2 Sensors ‘Tee’ Tutorial © 2015 Cochran Consulting, Inc. As a unit, place the PO2 sensor and cap assembly into the tee. The PO2 sensor wires will touch both sides of the tee. Lower the PO2 sensor and cap assembly completely into the tee where the threads start to engage. PO2 Sensor and Tee Install

Lifeguard ® PO2 Sensors ‘Tee’ Tutorial © 2015 Cochran Consulting, Inc. Thread the cap into the tee. The PO2 sensor will turn with the cap, so the wires will not be twisted. The external connector should be aligned with the tee so the PO2 cable will align with the hose in which the tee is inserted. The PO2 sensor cable will attach to the four pins of the cap connector. PO2 Sensor and Tee Install

Lifeguard ® PO2 Sensors ‘Tee’ Tutorial © 2015 Cochran Consulting, Inc. The cable is fully mated with the cap connector. The locking sleeve is threaded onto the cap connector until tight. PO2 Sensor and Tee Install

Lifeguard ® PO2 Sensors ‘Tee’ Tutorial © 2015 Cochran Consulting, Inc. Cochran Consulting, Inc. ISO 9001:2008 Cochran Consulting Firman Drive Richardson, TX Websites: