Omron Sysmac CJ Series, Operation Manual

Page: 84 / 117

61
Using the Alarm Output Function Section 3-10
3-10-2 Setting the Alarm Hysteresis
The hysteresis setting controls the ON/OFF switching of the alarm output, as
shown in the following diagram. This setting can be changed in the Initializa-
tion Data words allocated in the DM Area to the Temperature Control Unit.
The alarm hysteresis can be set independently for each loop’s alarms (alarm
1 and alarm 2) in the Initialization Data Area allocated to the Unit. The standard
setting is 0.2 s.
Note If the alarm hysteresis settings are changed, the new settings will not become
effective until the power is turned ON again or the Unit is restarted. Always
turn the power supply OFF and ON again or restart the Unit after changing
these settings.
3-10-3 Setting the Alarm SVs
The alarm SVs are indicated by “X” in the Alarm Modes table on page 60. Set
the alarm SVs in the corresponding words in the output area of the DM Area
words allocated to the Unit. (See
3-10-5 Summary of Alarm Output Function
Settings for the actual DM addresses of these words.)
■
About the Standby Sequence
The “standby sequence” disables the alarm output during Unit initialization,
i.e., until the PV leaves the alarm range. The alarm output will function the
next time the PV enters the alarm range.
For example with the standard “lower-limit alarm” mode, the PV is usually
lower than the set point when the power is turned ON, so the PV is within the
alarm range and the alarm output goes ON immediately. If Lower-limit Alarm
with Standby Sequence Mode is selected, the alarm will not be output until
after the PV rises above the alarm SP, leaves the alarm range, and then falls
below the alarm SP again.
7 Lower-limit alarm with standby
sequence
8 Absolute-value upper-limit
alarm
9 Absolute-value lower-limit
alarm
Setting Alarm mode Alarm output function
Alarm SV (X) is positive Alarm SV (X) is negative
ON
OFF
X
SP
ON
OFF
X
SP
ON
OFF
X
0
ON
OFF
X
0
ON
OFF
X
0
ON
OFF
X
0
ON
OFF
Alarm SV
Alarm SV
ON
OFF
Upper-limit
alarm
Lower-limit
alarm
Alarm hysteresis
Alarm hysteresis