
2408
i Indicator Engineering Manual
4.5.3
Alarm Configuration
Alarms are used to alert an operator when the process value has exceeded a pre-set level or when some other
fault condition has occurred. They normally switch an output - usually relay - to provide an interlock on a
machine/process or audio/visual indication to an operator.
The Model 2408
i
has four internal ‘soft’ alarms which are configured in the
<
AL
>
list below. A soft alarm means
indication only. To make a soft alarm activate a physical output it must be ‘attached’ to that output. See: section
4.5.8. ‘Relay Output Configuration’
ALARM DEFINITIONS:
The following alarm types can be configured:
Full Scale High
The Process Value is above a set high level
Full Scale Low
The Process Value is below a set low level
Deviation band
The difference between setpoint and the process value is outside a set band
Deviation high
The difference between setpoint and the process value is above a set value
Deviation low
The difference between setpoint and the process value is below a set value
Rate of change
The Process Value is changing faster than a set rate
AL
Alarm list
Option
Meaning
Default setting
Customer setting
AL 1
To select Alarm 1
Type
OFF
The alarm is disabled
Defined by the
ordering code,
otherwise
OFF
Alarm number
FSL
Full Scale Low alarm - main process value
1
2
3
4
FSH
Full Scale High alarm - main process value
dEv
Deviation band alarm - main process value
DHi
Deviation High alarm - main process value
DLo
Deviation Low alarm - main process value
dv1
Deviation band alarm - input 1
DH1
Deviation High alarm - input 1
DL1
Deviation Low alarm - input 1
dv2
Deviation band alarm - input 2
DH2
Deviation High alarm - input 2
DL2
Deviation Low alarm - input 2
FL2
Full Scale Low alarm on Process Value input 2
FH2
Full Scale High alarm on Process Value input 2
LSP
Master Setpoint Low alarm
HSP
Master Setpoint High alarm
FL1
Full scale low alarm on linearised input 1
FH1
Full scale high alarm on linearised input 1
rat
Rate of change alarm, minutes – main PV
raS
Rate of change alarm, seconds – main PV
rt1
Rate of change alarm, minutes - input 1
rS1
Rate of change alarm, seconds - input 1
rt2
Rate of change alarm, minutes - input 2
rS2
Rate of change alarm, seconds - input 2
Ltch
To select alarm
latching type
no
Non-latching
no
YES
Latched with automatic resetting (See note 1)
Eunt
Event output (See note 3)
mAn
Latched with manual resetting (See note 2)
bLoc
To select alarm
blocking
no
YES
No blocking
Blocked until first good (See note 4)
no
Sbr.t
To inhibit process
alarms in sensor
break
disA
EnAb
Disabled. Inhibits alarms (See note 5)
Enabled. Alarms operate when in sensor break
EnAb
The above sequence is repeated for:
<
AL 2
>
(alarm 2),
<
AL 3
>
(alarm 3) and
<
AL 4
>
(alarm 4)
Note 1
Automatic Resetting
means that, once the alarm has been acknowledged, it will automatically clear when it is no
longer true
Note 2
Manual resetting
means that the alarm must first clear before it can be reset
Note 3
Events
can be used to operate an output in the same way as an alarm but will NOT flash an alarm message, and can
be used to trigger external events. For example, an event output could be used to open/close a vent at a pre-set
temperature
Note 4
Blocking Mode.
After power on, the process value must first enter a good state before the alarm becomes active.
When once this process has been completed the alarm operates in its normal mode and does not become relevant
again until power to the indicator is turned off and on again. This is particularly useful for low alarms which can be
‘blocked’ while the process is warming up. It is advised that blocking alarms are not used with rate of change alarms
Note 5
Sbr.t
When this parameter is set to ‘Disabled’, all alarms from the process will be inhibited should a sensor break
condition occur. When Enabled process alarms will be shown (as in previous software versions) even in a sensor
break condition.
Part Number HA027240 Issue 5.0 Feb 2015
41
Содержание 2408i
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