D-Guard
2
28
11.
Detector Operating System
D-Guard
2
is shipped with the gas type and range configured per the end users requirements when purchased. In general,
since many of the gas related functional settings are common to many applications, D-Guard
2
has been setup with the
most commonly encountered configuration based on the selected gas type and range. For many end users and
applications, no further setup is required.
For those applications that require alternative configurations, D-Guard
2
includes a comprehensive user interface system
making modifications to system settings fast and efficient.
This same system gives access to commonly used calibration functions that will be required to be used on a regular basis
to maintain detector performance.
A menu map for all of the available screens is given in appendix c.
D-Guard
2
has a high resolution, high contrast LCD that provides clear and easy to read screens for all gas readings, status
messages and menu items. The detector uses four magnetically sensitive switch devices that operate as user buttons
(keys). The functionality of each button is context dependant, based on the menu screen in use. This system of 'soft-
keys' is described in section 10.3.1.
11.1.
Detector Power Up
For the first sixty seconds following power-up, D-Guard
2
displays the start-up screen. This is the detector 'warm-up'
phase and holds the instrument in a default condition while the gas sensors stabilise. This reduces unpredictable system
behaviour since the detector outputs a low fault current loop value during this phase. The connected system can identify
that the detector is in a low signal state and act accordingly. This start-up action is desirable because during the warm-
up period, the detector is essentially off-line and not reporting present gas values.
A numeric counter at the bottom of the display counts down from 60 to 0 as the warm-up time elapses.
After the 60 seconds time period expires, the detector moves to its main system read-out (Home) screen.
Initial Start-Up Screen.
Detector 'Home' Screen.
