Indicator N1500
NOVUS AUTOMATION
2/7
ALARMS
The indicator has 2 alarm outputs in the basic version and up to 4
alarms outputs optionally.
Each alarm has a corresponding LED message in the front panel to
show alarm status.
ALARM FUNCTIONS
The alarms can be set to operate in seven different modes. These
modes are shown in Table 2 and described below. The alarm can
also be set as ‘disabled’.
•
Sensor break -
Ierr
The alarm is triggered whenever the sensor breaks or is badly
connected.
•
Low alarm -
Lo
The alarm relay is triggered whenever the measured value is below
the alarm set point.
•
High alarm -
Ki
The alarm relay is triggered whenever the measured value is above
the alarm set point.
•
Differential low –
Dif.lo
Deviation alarm. Alarm relay is triggered whenever the difference
(deviation) between the Process Variable and the reference value
(
AlrEF
) is lower than the values defined in
SP.AL
. For this function,
the triggering point is defined as:
(
ALrEF
–
SP.AL
)
•
Differential High –
Dif.ki
Deviation alarm. Alarm relay is triggered when the difference
(deviation) between the Process Variable value and the reference
value (
AlrEF
) is greater than the value defined in
SPAL
. For this
function, the triggering point is defined as:
(
ALrEF
+
SP.AL
)
•
Differential (or Band) out of range –
Dif.ov
Deviation alarm. Alarm relay is triggered when the difference
(deviation) between the Process Variable value and the reference
value (
AlrEF
) has its modulus greater than the value configured in
SPAL
. For this function, the triggering point is defined as:
(
ALrEF
–
SP.AL
) and (
ALrEF
+
SP.AL
)
•
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
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 leds associated with the alarm always light up when the alarm
condition occurs, regardless of the current state of the output relay,
which may be de-energized momentarily due to a time delay.
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
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.
SPECIAL FUNCTIONS
MAXIMUM AND MINIMUM
The indicator memorizes the measured maximum and minimum
values (peak and valley). These two values are shown when pressing
the MAX or MIN keys. Pressing both keys simultaneously will clear
the memory for a new peak and valley detection.
SPECIAL FUNCTION KEY AND DIGITAL INPUT
The
key (special function key) in the frontal panel and the
optional digital input can execute special functions according to the
user selection. Fig. 8 shows how to activate the digital input. The
special functions for the
key and for the digital input are
explained as it follows.
•
Kold
- Freeze measured value
The hold function freezes the measured value showed in the display.
This function is toggled each time the
key is pressed or the
digital input is selected.
Whenever the indicator is in the hold mode a “
koLd
” message is briefly
displayed to show the operator that the displayed value is the frozen
value and not the current input reading.
•
Pkold
– Maximum value
The Peak Hold function shows the maximum value measured since
the last time the F key was pressed or the digital input activated.
Each activation of the
key or digital input triggers a new Peak
Hold level and the display resets with a new peak value.
•
rSt
- Clears maximum and minimum
This function works the same way as the MAX and MIN keys pressed
simultaneously, as explained in the 5.1 section. If this “
rSt
” function
is programmed, every touch of the
key or activation of the digital
input will clear the memory and a new level of maximum and
minimum values memorization will start.
