4 Operations
displaying the function of each button directly above it. The LCD screen displays the current mode and any warning messages, instructions and button functions.
4.1.1 Spinning Wheel
A “spinning wheel” appears in the upper left-hand corner of the LCD display to indicate that the alarms are enabled (any that are not defeated), or that scheduled zeroing (AutoZeroing) or scheduled spanning (AutoSpanning) may take place. If the spinning wheel does not appear, the alarms are disabled, and a scheduled zero or span is defeated. Note that there is a delay of several minutes before the spinning wheel appears whenever the Analyze mode is re-entered.
4.1.2 Cell Output Factor (Span Factor)
The expected life of the Micro-Fuel Cell sensor is about eight months. A guide to the relative life left in the cell can be found on status page 2 (see System Statistics near the end of this chapter) or retrieved from the serial port through the serial command SF. The span factor ranges from 0.00 to 1.00, with 1.00 representing full life expectancy. A span factor below 0.1 indicates that the Micro-Fuel Cell needs replacing.
4.2Modes of Operation
To use the system and select displayed options, press the button directly underneath the option you wish to select. There are eleven different menus:
Cold Start-Up:During the first startup, and when subsequent cold start- ups are chosen by the user, initial values set at the factory for alarms, I/O, calibration, zeroing and other data are used.
Upon cold start, zeroing and calibration should be performed before
accurate oxygen measurements are obtained. A system warm start is automati- cally performed on each subsequent power-up. For a warm start, previous user-input configuration data is preserved in RAM by battery-preserved memory in the system control module.
Calibration Zeroing: For the highest possible accuracy, the analyzer must be zeroed using an oxygen-free gas. By eliminating normal background “noise” from the sensor reading, zeroing resets the level referred to as the “zero” oxygen concentration.
If the analyzer is equipped with a scrubber, it is important to zero the analyzer with a near-zero gas connected to the sample port. The zeroing process automatically opens pneumatic valves on either side of the scrubber, and a gas with a high concentration of oxygen will react with the scrubber and necessitate replacement sooner.
4-2 | TELEDYNE ANALYTICAL INSTRUMENTS |
