Omega RD-MV100 Series User Manual page 36

1.5 Alarm Function
1-18
Upper limit alarm
Alarm occurrence
Alarm release
Measured/computed data
• Alarm delay upper limit alarm
An alarm occurs when the measured value remains above the alarm value for the
specified time period (delay period).
• Alarm delay lower limit alarm
An alarm occurs when the measured value remains below the alarm value for the
specified time period (delay period).
Alarm delay upper limit alarm example (T is the specified delay period)
Measured/computed data
X1
T1
• Alarm does not occur at T1, because the time period is shorter than the specified
delay period (T).
• The input exceeds the alarm value at X2, but the alarm does not occur. The alarm
occurs at X3 at which the specified delay period elapses (the time when the alarm
occurs is the time at X3).
• The input falls below the alarm value at X4 and the alarm is released.
• Difference upper limit alarm
An alarm occurs when the difference between the measured values of two channels
becomes greater than or equal to the alarm value.
Can be specified only on difference computation channels.
• Difference lower limit alarm
An alarm occurs when the difference between the measured values of two channels
becomes smaller than or equal to the alarm value.
Can be specified only on difference computation channels.
• Upper limit on rate-of-change alarm
The amount of change of the measured values over a certain time interval is checked.
An alarm occurs when the amount of increase becomes greater than or equal to the
specified value.
Can be specified only on measurement channels.
• Lower limit on rate-of-change alarm
The amount of change of the measured values over a certain time interval is checked.
An alarm occurs when the amount of decrease becomes greater than or equal to the
specified value.
Can be specified only on measurement channels.
Lower limit alarm
Measured
alarm value
/computed data
Alarm occurrence
X2 X3
T
Alarm occurrence
Alarm release
alarm value
X4
Alarm value
Alarm release