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3.3 & 3.4 Alarm Figures
3–4 Alarm
The controller has one alarm output. There are six types of
alarm functions and one dwell timer that can be selected, and
four kinds of alarm modes (ALMD) are available for each
alarm function (ALFN). Output 2 can be configured as an-
other alarm in addition to the alarm output. But output 2 only
provides four kinds of alarm functions and only normal alarm
mode is available for this alarm. When output 2 is used as an
alarm, SP2 sets the trigger point. SP3 sets the trigger point for
Alarm.
A
process alarm
sets absolute trigger levels. When the
process is higher than SP3, a process high alarm (PV.HI) oc-
curs, and the alarm is off when the process is lower than SP3-
ALHY. When the process is lower than SP3, a process low
alarm (PV.LO) occurs, and the alarm is off when the process
is higher than SP3+ALHY. A process alarm is independent of
the set point.
A
deviation alarm
alerts the user when the process deviates
from the set point. When the process is higher than SV+SP3,
a deviation high alarm (DE.HI) occurs, and the alarm is off
when the process is lower than SV+SP3-ALHY. When the
process is lower than SV+SP3, a deviation low alarm
(DE.LO) occurs, and the alarm is off when the process is
higher than SV+SP3+ALHY. The trigger level of the devia-
tion alarm moves with the set point.
A
deviation band alarm
presets two trigger levels relative to
the set point. The two trigger levels are SV+SP3 and SV-SP3
for alarm. When the process is higher than (SV+SP3) or lower
than (SV-SP3), a deviation band high alarm (DB.HI) occurs.
When the process is within the trigger levels, a deviation band
low alarm (DB.LO) occurs.
There are four types of alarm modes available for each alarm
function. These are: normal alarm, latching alarm, holding
alarm and latching/holding alarm. They are described as fol-
lows:
Normal alarm: ALMD=NORM
When a normal alarm is selected, the alarm output is de-ener-
gized in the non-alarm condition and energized in an alarm
condition.
Latching alarm: ALMD=LTCH
If a latching alarm is selected, once the alarm output is ener-
gized, it will remain unchanged even if the alarm condition is
cleared. The latching alarm is reset when the RESET key is
pressed after the alarm condition is removed.
Holding alarm: ALMD=HOLD
A holding alarm prevents an alarm when the control is pow-
ering up. The alarm is enabled only when the process reaches
the set point value. Afterwards, the alarm performs the same
function as a normal alarm.
Latching/holding alarm: ALMD=LT.HO
A latching/holding alarm performs both holding and latching
functions. The latching alarm is reset when the RESET key is
pressed after the alarm condition is removed.
Alarm failure transfer
is activated as the unit enters failure
mode. The alarm will go on if ALFT is set for ON and go off
if ALFT is set for OFF. The unit will enter failure mode when
a sensor break occurs or if the A-D converter of the unit fails.
Figure 3.4 Output 2 Process Low Alarm
Figure 3.3 Output 2 Deviation High Alarm
Содержание PCM10005
Страница 3: ...Page 3 of 16 1 5 Menu Overview...
Страница 5: ...Page 5 of 16 Parameter Descriptions page 2 of 2...
Страница 6: ...Page 6 of 16 Alarm Wiring...
Страница 14: ...Page 14 of 16 Table A 1 Error Codes and Corrective Actions...