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4.3 ALARM
The SCANNER provides a precautionary
ALARM
warning to alert the user to potentially
hazardous or dangerous input conditions. The SCANNER monitors all enabled scanner
channels’ current analog input readings and compares each channel’s reading with a user-
configurable
ALARM
threshold. If any channel’s
ALARM
threshold is exceeded, the
SCANNER TRIPs an
ALARM
condition and blinks the
ALARM
indicator LED on the front
panel. A SCANNER
ALARM
is
not
latched
and clears if no channel’s
ALARM
threshold is
faulted.
4.4 SHUTDOWN
The SCANNER provides a protective
SHUTDOWN
fault to guard against hazardous or
dangerous fault conditions. The SCANNER monitors all enabled scanner channels’ current
analog input readings and compares each channel’s reading with a user-configurable
SHUTDOWN
threshold. If any channel’s
SHUTDOWN
threshold is exceeded, the
SCANNER TRIPs a
SHUTDOWN
condition and blinks the
SHUTDOWN
indicator LED on
the front panel.
When a
SHUTDOWN
occurs, the SCANNER saves the channel that caused the
SHUTDOWN
to non-volatile memory as the First-Out channel. This First-Out channel is the
first channel that the SCANNER detects in a
SHUTDOWN
fault state. The SCANNER
displays the First-Out cause of the
SHUTDOWN
on the Main SCANNER Screen (See
Section 5.2.3). A SCANNER
SHUTDOWN
is
latched
and is not cancelled until
acknowledged by a RESET (See Section 4.1).
At the time of a
SHUTDOWN
, other scanner channels may be in a
SHUTDOWN
fault state.
Since several channels may be faulted, it is possible that another scanner channel besides
the First-Out channel caused the actual
SHUTDOWN
—the SCANNER merely detected and
labeled one faulted channel before the actual First-Out channel.
To aid the user in analyzing a SCANNER
SHUTDOWN
, the SCANNER also takes a Snap
Shot of all enabled scanner channels’ analog input readings at the time of the
SHUTDOWN
and saves these Snap Shots to non-volatile memory. These Snap Shot values are displayed
on the SNAP Screen (See Section 5.2.7) and may be viewed after the user acknowledges
the
SHUTDOWN
condition via a SCANNER RESET. Only one set of
SHUTDOWN
Snap
Shot values is saved to memory at any one time. When a subsequent
SHUTDOWN
occurs,
the new Snap Shot values overwrite the old values in memory.
