Siemens Moore 353 User Manual page 53

UM353-1
Alarm Types
HI compares the process input with the limit setting
and it will trip the alarm status high (1) when the
process is equal to or higher than the limit setting. The
alarm status will clear (0) when the process is less
than the limit setting minus the deadband.
LO compares the process input with the limit setting
and it will trip the alarm status high (1) when the
process is equal to or less than the limit setting. The
alarm status will clear (0) when the process is greater
than the limit setting plus the deadband.
HI DEV compares the difference between the process
input and the deviation input (P-D) with the limit
setting and it will trip the alarm status high (1) when
(P-D) is equal to or greater than the limit setting. The
alarm status will clear (0) when (P-D) is less than the
limit setting minus the deadband.
LO DEV compares the difference between the
deviation input and the process input (D-P) with the
limit setting and it will trip the alarm status high (1)
when (D-P) is equal to or greater than the limit
setting. The alarm status will clear (0) when (D-P) is
less than the limit setting minus the deadband.
DEV compares the absolute difference between the
process input and the deviation input |P-D| with the
limit setting and it will trip the alarm status high (1)
when |P-D| is equal to or greater than the limit setting.
The alarm status will clear (0) when |P-D| is less than
the limit setting minus the deadband.
OR compares the process input with the range limits referenced by the range pointer parameter and will trip the
alarm status high (1) when the process is equal to or greater than the high limit or equal to or less than the low limit.
The alarm status will clear (0) when the process is less than the high limit minus the deadband or greater than the
low limit plus the deadband.
POWER UP - During a warm start, all alarms will be handled the same as during a hot start: outputs are initialized
at the last state, all previously acknowledged alarms are treated as acknowledged, and any new alarms will be
processed on the first scan cycle. On a cold start, all alarm outputs are initialized at 0, all alarms are reset and any
new alarms, based on the block inputs, will be processed during the first scan cycle. Also, during a cold start,
alarms will be enabled or disabled as determined by the PU ENable parameters.
Alarm Status
Alarm status is available with Modbus communication or the Local Instrument Link option for alarm management
at a remote location. The alarm status is available in coils with Modbus communication or the same information is
packed into a single word (Alarm Status Word) with LIL communication. Detailed information can be found in the
Network Communications section of this document.
March 2003
LIMIT
HI
Input P
Input P
LO
LIMIT
HI
Input P
LIMIT
+
DEV
Input D -
LO
Input P
LIMIT
-
DEV
Input D
+
Input P
LIMIT
DEV +
ABS
Input D -
P - MINSCALE
Input P
OR
P -MAXSCALE
BLOCK DIAGRAM
Function Blocks
_
Alarm Status
_
Alarm Status
_
Alarm Status
_
Alarm Status
_
Alarm Status
_
Alarm Status
Logic OR
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