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3. Alarm type
Alarm type can be selected from the following six types for each alarm point.
1) Upper limit alarm (H)
Alarm is activated when the measured value of specified channel reaches or exceeds an alarm value.
Set value ··························· alarm value, deadband
Activation condition ·············· specified CH data
≥
alarm value
Reset condition ··················· specified CH data < (alarm value – deadband)
2) Lower limit alarm (L)
Alarm is activated when the measured value of specified channel reaches or falls below an alarm value.
Set value ··························· alarm value, deadband
Activation condition ·············· specified CH data
≤
alarm value
Reset condition ··················· specified CH data > (alarm value + deadband)
3) Difference upper limit alarm (B)
Alarm is activated when the difference calculated by subtracting the measured value of compared channel
from the measured value of specified channel reaches or exceeds an alarm value.
Set value ··························· alarm value, compared CH, deadband
Activation condition ·············· (specified CH data – compared CH data)
≥
alarm value
Reset condition ··················· (specified CH data – compared CH data) < (alarm value – deadband)
4) Difference lower limit alarm (S)
Alarm is activated when the difference calculated by subtracting the measured value of compared channel
from the measured value of specified channel reaches or falls below an alarm value.
Set value ··························· alarm value, compared CH, deadband
Activation condition ·············· (specified CH data – compared CH data)
≤
alarm value
Reset condition ··················· (specified CH data – compared CH data) > (alarm value + deadband)
5) Rate-of-change upper limit alarm (U)
Alarm is activated when the measured value variation width of specified channel in the reference period [
∆
t
sec] is at the plus side and equal to or higher than an alarm value.
Set value ··························· alarm value (absolute value with any sign), reference period [
∆
t sec],
deadband
The reference period is set within the range of 0 to 600.0sec. Alarm judgment cycle is as follows:
0.1sec (
∆
t is set to 2sec or less)
∆
t/2sec (rounding up to whole number)
6) Rate-of-change lower limit alarm (D)
Alarm is activated when the measured value variation width of specified channel in the reference period [
∆
t
sec] is at the minus side and equal to or higher than an alarm value.
Set value ··························· alarm value (absolute value with any sign), reference period [
∆
t sec],
deadband
The reference period is set within the range of 0 to 600.0sec. Alarm judgment cycle is as follows:
0.1sec (
∆
t is set to 2sec or less)
∆
t/2sec (rounding up to whole number)
