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13.1.4
Setting Span Gas Concentration
This setting allows the user to enter the gas concentration value being used to calibrate the D-Guard
2
D-Guard
is shipped with a default value that relates to the gas range selected. This value may be set to match the most
commonly used concentration value that the user will present to the detector during span calibrations and DRT tests.
Note, if a calibration gas is used that does not match the value set into this function, auto-span and DRT checks will
not be accurate.
Note: For most measurement types, concentration adjustment is settable to one decimal place. For
measurement types with full scale ranges of 1ppm / 2ppm / 5ppm and for Infra-Red sensor types, 2 decimal
places of calibration gas setting value is provided.
Default Span Gas Value
From the default calibration gas value, use the up and down
soft-keys to increase or decrease the value. The up and down
soft-keys are accelerated so continuing to hold the key
changes the value more quickly. Once a change is made the
'home' icon changes to the 'save' icon.
13.2. Alarm Configuration
2
D-Guard
contains 2 gas concentration based alarms that provide indication that the measured gas has reached or
exceeded a certain threshold. This threshold is the alarm set-point value stored within the D-Guard
settings.
When an alarm set-point is reached, a number of actions are taken depending on the variant of D-Guard
For detector versions with optional relays fitted, the appropriate relay (warn or danger) will change state. For detectors
without relays but with HART communications, the alarm state is transmitted over the digital communication link. For
Detectors without relays or HART communications, alarm conditions are signalled on the display as messages and icons.
As with the sensor configuration, most, if not all of the settings are pre-set during the detectors manufacture with the
most commonly encountered configuration. However, the end user may wish to modify these defaults to match a
particular application.
The descriptions relating to alarm configurations given in the next sections relate to 'Alarm 1', however, the process is
identical for making changes to 'Alarm 2'
Modified Span Gas Value
Once the change is made and the 'save' icon is showing, the
selection can be committed and saved to eeprom. Once
saved, the 'save' icon reverts to the 'back' icon allowing the
previous setup function to be accessed if required. To move to
the Set Auto-Zero screen, operate the 'NEXT PARAMETER'
soft-key.
To return home, keep pressing the back soft-key until the
main sensor setup screen is displayed with the home icon
showing.
41
2
D-Guard
2
.
2
configuration
2
being used.
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