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Ierr, Dif.lo, Dif.ki – NOVUS n1500lc User Manual

Page 4: Dif.ov, Dif.in

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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.