Yokogawa Touch Screen GP20 - Manual (Page 34)

1-20
IM 04L51B01-01EN
Explanation
Alarm Type
The character inside the parentheses is the symbol denoting each alarm.
High Limit Alarm (H)
Alarm value
Alarm output ON
Alarm output ON
Hysteresis Measured value
Low Limit Alarm (L)
Alarm output ON
Alarm value
Measured value Hysteresis
Alarm output ON
Delay period
Alarm value
Measured value
Delay High Limit Alarm (T) Delay Low Limit Alarm (t)
Alarm output ON
Delay period
Alarm value
Measured value
High Limit on Rate-of-Change Alarm (R) Low Limit on Rate-of-Change Alarm (r)
Alarm value
Hysteresis
Difference in the measured values of two channels
Difference High Limit Alarm (h) Difference Low Limit Alarm (l)
Alarm output ON
Alarm value
Hysteresis
Difference in the measured values of two channels
Change in the
measured value
Measured value
Time
Interval (t2 – t1)
T2
T1
t1 t2
Change in the measured value
Measured value
Time
Interval (t2 – t1)
Amount of change
in the setting
| |
T2
T1
t1 t2
T1 – T2
Amount of change
in the setting
| | T1 – T2
High Limit Alarm and Low Limit Alarm
An alarm is activated when the measured value is greater or less than or equal to the alarm
value.
Delay High Limit Alarm and Delay Low Limit Alarm
An alarm is activated if measured values remain greater or less than or equal to the alarm
value for a specified time period (delay period).
High Limit on Rate-of-Change Alarm and Low Limit on Rate-of-Change Alarm
An alarm is activated if the increasing or decreasing rate-of-change of measured values over
a certain interval is greater than or equal to the specified value.
The alarm value of an rate-of-change alarm is set using an absolute value. The interval is
derived using the following equation and set using the number of samples.
Interval = the scan interval × the number of samples
For the number of samples, see page 1-142 in section 1.18.2, “Setting the Interval for
Calculating the Rate-of-Change for Rate-of-Change Alarms”.
Difference High Limit Alarm and Difference Low Limit Alarm
An alarm is activated when the difference in the measured values of two channels is greater
or less than or equal to the specified value.
This alarm can be specified on measurement channels set to difference calculation.
1.2 Configuring AI Channels (Analog input (including DI) channels)