Allen-Bradley Logix5000 Reference Manual page 60

Chapter 1 FactoryTalk Alarms and Events Logix-based Instructions (ALMD, ALMA)
Input Parameter Data Type
ROCPosSeverity DINT
ROCNegLimit REAL
ROCNegSeverity DINT
ROCPeriod REAL
Output Parameter Data Type
EnableOut BOOL
InAlarm BOOL
AnyInAlarmUnack BOOL
HHInAlarm BOOL
HInAlarm BOOL
LInAlarm BOOL
LLInAlarm BOOL
ROCPosInAlarm BOOL
ROCNegInAlarm BOOL
ROC REAL
HHAcked BOOL
HAcked BOOL
LAcked BOOL
LLAcked BOOL
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Description
Severity of the increasing rate-of-change condition. This does not affect processing of alarms by the
controller, but can be used for sorting and filtering functions at the alarm subscriber.
Valid = 1...1000 (1000 = most severe; 1 = least severe).
Default = 500.
Limit for a decreasing rate-of-change in units per second. Detection is enabled for any value > 0.0 if
ROCPeriod is also > 0.0.
Valid = 0.0...maximum possible float.
Default = 0.0.
Severity of the decreasing rate-of-change condition. This does not affect processing of alarms by the
controller, but can be used for sorting and filtering functions at the alarm subscriber.
Valid = 1...1000 (1000 = most severe; 1 = least severe).
Default = 500.
Time period in seconds for calculation (sampling interval) of the rate of change value. Each time the
sampling interval expires, a new sample of In is stored, and ROC is recalculated.
Rate-of-change detection is enabled for any value > 0.0.
Valid = 0.0...maximum possible float.
Default = 0.0.
Description
Enable output.
Alarm active status. Set when any alarm condition is active. Cleared when all alarm conditions are
not active (normal status).
Combined alarm active and acknowledged status. Set when any alarm condition is detected and
unacknowledged. Cleared when all alarm conditions are normal (inactive), acknowledged, or both.
High High alarm condition status. Set when a High High condition exists. Cleared when no High High
condition exists.
High alarm condition status. Set when a High condition exists. Cleared when no High condition exists.
Low alarm condition status. Set when a Low condition exists. Cleared when no Low condition exists.
Low Low alarm condition status. Set when a Low Low condition exists. Cleared when no Low Low
condition exists.
Positive rate-of-change alarm condition status. Set when a positive rate-of-change condition exists.
Cleared when no positive rate-of-change condition exists.
Negative rate-of-change alarm condition status. Set when a negative rate-of-change condition exists.
Cleared when no negative rate-of-change condition exists.
Calculated rate-of-change of the In value. This value is updated when the instruction is scanned
following each elapsed ROCPeriod. The ROC value is used to evaluate the ROCPosInAlarm and
ROCNegInAlarm conditions.
ROC = (current sample of In – previous sample of In) / ROCPeriod.
High High condition acknowledged status. Set when a High High condition is acknowledged. Always
set when AckRequired is cleared. Cleared when a High High condition is not acknowledged.
High condition acknowledged status. Set when a High condition is acknowledged. Always set when
AckRequired is cleared. Cleared when a High condition is not acknowledged.
Low condition acknowledged status. Set when a Low condition is acknowledged. Always set when
AckRequired is cleared. Cleared when a Low condition is not acknowledged.
Low Low condition acknowledged status. Set when a Low Low condition is acknowledged. Always
set when AckRequired is cleared. Cleared when a Low Low condition is not acknowledged.
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011