NOVUS n1500lc - Manual (Page 4)

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4.1.7 Differential (or Band) within range – Dif.In
Deviation alarm. Alarm relay is triggered when the difference (deviation) between the Process
Variable value and the reference value (AlrEF) has its modulus lower than the value defined in
SPAL. For this function, the triggering points are defined as:
(ALrEF – SP.AL) and (ALrEF + SP.AL)
TYPE PROMPT ACTION
Disabled Off Alarm is inactive
Sensor Break (input Error) Ierr Alarm will go ON if sensor breaks
Low Alarm
(Low)
Lo
Alarm SP
PV
High Alarm
(High)
Ki
Alarm SP
PV
Differential Low
(differential Low)
Dif.lo
PV
AL SP + Deviation AL SP
Differential High
(differential High)
Dif.ki PV
AL SP + Deviation AL SP
Differential out of range
(differential out)
Dif.ov
PV
AL SP + Deviation
Positive Deviation
AL SP AL SP - Deviation
Differential within range
(differential Within)
Dif.In
PV
AL SP + Deviation
Negative Deviation
AL SP AL SP - Deviat.
Table 2 - Alarm functions
5.2 ALARM TIMER
The alarms can be configured to perform timing functions. The configuration allows the alarm output
to be delayed, or to deliver a single pulse or a train of pulses. The delay, the pulse width and the
period are defined by the user.
Table 3 shows these advanced functions. Times T1 and T2 can be programmed from 0 to 6500
seconds. Programming 0 (zero) in the timer parameters T1 and T2 disables the timer function.
The display alarm indicators (A1, A2, A3 or A4) remain ON while their respective alarm conditions are
present, regardless of the current output status, which may be temporarily off due to the timer action.
Advanced
Function
T1 T2 ACTION
Normal
Operation
0 0
Alarm Event
Alarm
Output
Delayed 0 1 s to 6500
s
Alarm Event
Alarm
Output
T2
Pulse 1 s to 6500
s
0
Alarm Event
Alarm
Output T1
Oscillator 1 s to 6500
s
1 s to 6500
s
Alarm Event
Alarm
Output
T1 T2 T1
Table 3 - Timer Alarm Functions
5.3 ALARM INITIAL BLOCKING
The initial blocking option inhibits the alarm from being recognized if an alarm condition is present
when the controller is first energized. The alarm will be triggered only after the occurrence of a non
alarm condition followed by a new occurrence for the alarm.
The initial blocking is disabled for the sensor break alarm function.