Alarm Value; Alarm Hysteresis; Close In Alarm/Open In Alarm - Omron E5CK User Manual

CHAPTER 3 BASIC OPERATION
J Alarm hysteresis
F Standby
sequence
J Close in alarm/open in alarm
F Summary of
alarm operations
3--8
• The hysteresis of alarm outputs when alarms are switched ON/OFF can
be set as follows.
Upper limit alarm

Alarm hysteresis

ON
OFF

Alarm value

• Alarm hysteresis is set independently for each alarm in the "alarm 1 to
3 hysteresis" parameters (level 2 mode). Factory setting is "0.02:
0.02%FS".
• "Standby sequence" is a function for unconditionally turning alarm out-
put OFF when the process value has left the alarm range once and it next
enters the alarm range.
• For example, when the alarm type is set to "deviation lower limit," gener-
ally the process value is within the alarm range, and alarm output
become ON as it is as the process value when the power is turned ON is
smaller than the set point. However, if the alarm type is set to "deviation
lower limit with standby sequence", alarm output first becomes ON
when the process value exceeds the alarm setting value to leave the
alarm range and once again falls below the alarm value.
• When the controller is set to "close in alarm," the status of the alarm out-
put function is output as it is. When set to "open in alarm," the status of
the alarm output function is output inverted.
Close in alarm Close in alarm
Open in alarm Open in alarm
• Alarm type and close in alarm (normally open)/open in alarm (normally
close) can be set independently for each alarm.
• Close in alarm/open in alarm is set in the "alarm 1 to 3 open in alarm"
parameters (setup mode). Factory setting is [
The figure below visually summarizes the above description of alarm
operations (when alarm type is set to "lower limit alarm (deviation) with
standby sequence"):
Alarm type: lower limit alarm (deviation)
with standby sequence
PV
Alarm value
Standby sequence
canceled
Alarm output
(close in alarm)
Lower limit alarm
ON
OFF
Alarm value
Output
Alarm
ON ON
OFF OFF
ON OFF
OFF ON
Alarm hysteresis
Close (ON)
Open (OFF)
Alarm hysteresis
Output LED
Lit
Not lit
Lit
Not lit
] "close in alarm".
Time