Rainbow Electronics DS2422 - Manual (Page 18)

DS2422
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ALARM STATUS
The fastest way to determine whether a programmed alarm threshold was exceeded during a mission is through
reading the Alarm Status Register. In a networked environment that contains multiple DS2422-based dataloggers
the devices that encountered an alarm can quickly be identified by means of the Conditional Search command (see
ROM Function Commands). The data and temperature alarm only occurs if enabled (see Temperature Sensor
Alarm and Serial Input Alarm). The BOR alarm is always enabled.
Alarm Status Register Bitmap
ADDR b7 b6 b5 b4 b3 b2 b1 b0
0214h BOR 1 1 1 DHF DLF THF TLF
There is only read access to this register. Bits 4 to 6 have no function. They always read 1. All five alarm status bits
are cleared simultaneously when the Clear Memory function is invoked. See Memory and Control Functions for
details.
Register Details
BIT DESCRIPTION BIT(S) DEFINITION
TLF: Temperature Low
Alarm Flag
b0
If this bit reads 1, there was at least one temperature conversion during
a mission revealing a temperature equal to or lower than the value in
the Temperature Low Alarm Register. A forced conversion can affect
the TLF bit. This bit can also be set with the initial alarm in the SUTA =
1 mode.
THF: Temperature High
Alarm Flag
b1
If this bit reads 1, there was at least one temperature conversion during
a mission revealing a temperature equal to or higher than the value in
the Temperature High Alarm Register. A forced conversion can affect
the THF bit. This bit can also be set with the initial alarm in the SUTA =
1 mode.
DLF: Data Low Alarm Flag b2
If this bit reads 1, there was at least one data value read from the serial
data interface during a mission revealing a value equal to or lower than
the value in the Data Low Alarm Register. A forced conversion can
affect the DLF bit.
DHF: Data High Alarm
Flag
b3
If this bit reads 1, there was at least one data value read from the serial
data interface during a mission revealing a value equal to or higher
than the value in the Data High Alarm Register. A forced conversion
can affect the DHF bit.
BOR: Battery On Reset
Alarm
b7
If this bit reads 1, the device has performed a power-on-reset. This
occurs when the VBAT power source gets first connected at assembly
or when the power supply gets interrupted. The trim settings need to
be restored for proper function. Any data found in the datalog memory
should be disregarded.
GENERAL STATUS
The information in the general status register tells the host computer whether a mission-related command was
executed successfully. Individual status bits indicate whether the DS2422 is performing a mission, waiting for a
temperature alarm to trigger the logging of data or whether the data from the latest mission has been cleared.
General Status Register Bitmap
ADDR b7 b6 b5 b4 b3 b2 b1 b0
0215h 1 1 0 WFTA MEMCLR 0 MIP 0
There is only read access to this register. Bits 0, 2, 5, 6, and 7 have no function.