i
7
TABLE 4 :
Below listed points will appear only if O/P2 is selected as an Alarm mode. In Alarm mode, Controller
continuously compares PV with either SP (for deviation or Band -alarm) or an independent Alarm set points (for
process high and process low alarm). HYS2 in Control list decides when to switch OFF the Alarm.
Low Alarm : OP2 activates when PV<SP2.
OUTPUT-2 ON
OUTPUT-2 OFF
SP2
PV
SP2
OUTPUT-2 OFF
OUTPUT-2 ON
PV
High Alarm : OP2 activates when PV>SP2.
OUTPUT-2 OFF
OUTPUT-2 ON
SP2
PV
Direct acting
SP2
OUTPUT-2 ON
OUTPUT-2 OFF
PV
Reverse acting
Band Alarm : OP2 activates when PV falls outside the band w.r.t. SP1 in either
direction.
OUTPUT ON
OUTPUT ON
PV
SP1
SP2
SP2
OUTPUT OFF
OUTPUT OFF
OUTPUT OFF
PV
SP1
SP2
SP2
OUTPUT ON
User can select direct Alarm Logic in which OP2 will be ON under alarm condition;
otherwise OFF (used for audio visual alarm).
User can select Reverse Alarm Logic in which OP2 will be ON in normal
conditions & will be OFF under alarm conditions (used to trip the process in alarm
conditions).
If this parameter is set as ‘YES’ & Alarm condition persists, it will Disable Alarm
O/P at power ON.
If this parameter is set as ‘NO’ & Alarm condition persists, it will Enable Alarm O/P
at power up.
Once the Alarm is activated, User has following three options to de-activate it.
When PV falls within the programmed limits The Alarm will be de-activated
automatically.
Once the alarm is activated, it remains activated until acknowledged manually by
UP key.
Once the alarm is activated, it can be de-activated either by pressing UP key or
when PV falls within the alarm limits.
If Enabled, User can View & edit the Alarm Set point in USER list.
If disabled, User can not View or edit Alarm Set Point in USER list.
High Deviation Alarm : OP2 activates when PV is greater than SP1 ± set
deviation value
OUTPUT ON
PV
SP1
OUTPUT OFF
OUTPUT OFF
+Ve
dev
PV
Sp1
OUTPUT ON
Low Deviation Alarm : OP2 activates when PV is less than SP1 ± set deviation
value
OUTPUT OFF
PV
OUTPUT ON
OUTPUT ON
PV
OUTPUT OFF
SP2
SP2
SP2
SP2
OUTPUT ON
PV
SP1
OUTPUT OFF
OUTPUT ON
PV
OUTPUT OFF
SP2
SP2
OUTPUT OFF
PV
SP1
OUTPUT ON
OUTPUT OFF
PV
OUTPUT ON
SP2
SP2
-Ve
dev
+Ve
dev
+Ve
dev
+Ve
dev
-Ve
dev
-Ve
dev
-Ve
dev
ALARM
TYPE
ALARM
LOGIC
ALARM
INHIBIT
ALARM
ACK.
ALARM
SET
POINT
Low
Direct
No
Auto
Enable
PARA
METER
UPPER
DISPLAY
LOWER
DISPLAY
DESCRIPTION
DEFAULT
OIM Px-X28 V2.0 Page 7 of 9
