The O2 Master module is in control of a number of ‘slave’ modules (CO2 modules, Sample Processors or Sample Manifolds).
The O2 Master module communicates with its connected slaves by means of an RS485 connection (iNET bus). The module also provides Ethernet communications for use within an integrated system, and this module provides master control for the system.
The %O2 sensor module provides a reading of percentage O2 concentration, as measured reference to 1-atmosphere. This reading is corrected to provide an accurate reading relative to standard atmospheric conditions (1013.25 mbars) regardless of local atmospheric pressure. Each module has a graphics / text display (VFD display) used to provide the operator with useful system information. This display is used for displaying various ‘pages’ of information, and uses three momentary pushbutton switches for navigating the various menus and displays.
The main display is of LED type for clear "at a glance" viewing from a good distance. The VFD (Vacuum Fluorescent Display) also provides clear viewing from any angle.
The oxygen sensor used inside this module is a paramagnetic type, which unlike fuel-cell type oxygen sensors, is highly accurate, responds quickly, and has an indefinite service life. This type of sensor can achieve a reading accuracy of 0.05% of measured value and thus meets the specification dictated by DNV & Lloyds at 300m water depth.
The O2 Master, as well as having Ethernet communications, can also provide two high resolution (16-bit) analogue 4-20mA outputs which are configurable for various outputs such as corrected or uncorrected readings or barometric pressure. This, together with an alarm status contact, enables the unit to replace a conventional analyser which provides a 4-20mA output for PLC/SCADA/HMCS system.
Both an O2 & CO2 unit can provide two 4-20mA analogue outputs giving 4 outputs per system.