Supplementary Explanation Of Functions; A-1-1 Changing Set Values During Output Of Process Value Alarm Or Rate-Of-Change Alarm; Alarm - Omron CJ Series Operation Manual

Appendices
A-1 Supplementary Explanation of
Functions
The following supplements the explanation given in 1-2 Features and Functions.
A-1-1 Changing Set Values during Output of Process Value Alarm or
Rate-of-change Alarm
HH (High High Limit) and H (High Limit) Alarms
When the alarm set value is raised while the alarm output is ON, the alarm output will be turned OFF
when the following condition is satisfied.
Input value < (alarm set value after change – hysteresis)
The alarm output will first turn OFF when the input value falls below the set value (with the hysteresis
included).
LL (Low Low Limit) and L (Low Limit) Alarms
When the alarm set value is lowered while the alarm output is ON, the alarm output will be turned OFF
when the following condition is satisfied.
Input value > (alarm set value after change + hysteresis)
When the hysteresis part alone of the input value is greater than the set value, the alarm output will turn
OFF for the first time.
Example: HH and H Limit Alarms
Alarm set value raised.
Alarm set value further raised.
A-2
Hysteresis
H, HH alarm set value
With present value at this point, alarm output turns ON.
Hysteresis
H, HH
alarm set value
With present value at this point, alarm output remains ON.
Hysteresis
H, HH alarm set value
With present value at this point, alarm output turns OFF.
CJ-series Analog I/O Units Operation Manual for NJ-series CPU Unit(W498)
Input value (Process value,
rate-of-change value)
Input value (Process value, rate-of-
change value)
Input value (Process value,
rate-of-change value)