Omron E5AZ, Руководство пользователя

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63
Alarm Hysteresis
Section 4-2
Lower-limit Temperature Input Shift Value
Upper-limit Temperature Input Shift Value
4-2 Alarm Hysteresis
• The hysteresis of alarm outputs when alarms are switched ON/OFF can
be set as follows:
• Alarm hysteresis is set independently for each alarm in the “alarm hyster-
esis 1" to “alarm hysteresis 3” parameters (advanced function setting
level).
• The default is 0.2 (
°
C/
°
F) for Controllers with Thermocouple/Resistance
Thermometer Universal-inputs and 0.02% FS for Controllers with Analog
Inputs.
4-2-1 Standby Sequence
• The standby sequence can be used so that an alarm will not be output
until the process value leaves the alarm range once and then enters it
again.
• For example, with a lower limit alarm, the process value will normally be
below the set point, i.e., within the alarm range, when the power supply is
turned ON, causing an alarm to be output.
If the lower limit alarm with a standby sequence is selected, an alarm will
not be output until the process value increases above the alarm set value,
i.e., until it leaves the alarm range, and then falls back below the alarm set
value.
Restart
• The standby sequence is canceled when an alarm is output. It is, how-
ever, restarted later by the “standby sequence reset” parameter
(advanced function setting level). For details, refer to the “standby
sequence reset” parameter in
SECTION 5 Parameters .
4-2-2 Alarm Latch
• The alarm latch can be used to keep the alarm output ON regardless of
the temperature once the alarm output has turned ON. The alarm output
will turn OFF when the power is turned OFF.
• The alarm output can also be turned OFF by switching to the initial setting
level, communications setting level, or advanced function setting level.
C
insl
-27.3
Lower-limit
temperature
input shift
value
insl
=
0
−
40
105
−
40
×
{(110
−
105)
−
(25
−
40)} + (25
−
40) =
−
27.3 (
°
C)
C
insh
52.7
Upper-limit
temperature
input shift
value
insh
=
260
−
40
105
−
40
×
{(110
−
105)
−
(25
−
40)} + (25
−
40) = 52.7 (
°
C)
ON
OFF
ON
OFF
Upper-limit alarm
Alarm hysteresis
Alarm value
Lower-limit alarm
Alarm hysteresis
Alarm value