Controller N2000
NOVUS AUTOMATION 3/11
The alarm functions are described in Table 3.
No active alarm. This output can be used as a
digital output to be set by the serial
communication.
Alarm will be ON if PV sensor breaks, input signal
is out of range or Pt100 is shorted.
Event Alarm
(ramp and
Soak)
Can be activated at a specific segment of ramp
and soak program.
Low Alarm
negative SPAn
HIGH
Differential
positive SPAn
negative SPAn
negative SPAn
Table 3 - Alarm functions
ALARM TIMER FUNCTIONS
The controller alarms can be configured to perform 4 timer modes:
• Continuous (normal mode).
• One pulse with defined duration;
• Delayed activation;
The illustrations in Table 4 show the behavior of the alarm output for
various combinations of times T1 and T2. The timer functions can be
configured in parameters
Table 4 - Advanced Timer Alarm.
The LEDs associated to the alarms will light when the alarm
condition is recognized, not following the actual state of the output,
which may be temporarily OFF because of the temporization.
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 actuate 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.
SQUARE ROOT EXTRACTION
Available when input type 19 is selected. The indicator displays the
square root of the current signal input applied to terminals 22 and 24.
ANALOG RETRANSMISSION OF PV AND SP
The analog output, when not used for control purposes, is available
for retransmitting the SV and SP values in 0-20 or 4-20 mA. This
analog output is electrically isolated from other inputs and outputs.
The analog output signal is scaleable, with the output range
determined by the values programmed in the parameters “
”. To obtain a voltage output, connect a resistor shunt to
the current output terminals.
It is possible to obtain a voltage output by installing a resistor shunt
(550 Ω max.) to the current output terminals (terminals 7 and 8). The
actual resistor value depends on the desired output voltage span.
SOFT START
The soft-start feature avoids abrupt variations in the power delivered
to the load regardless of the system power demand.
This is accomplished by defining a limiting ramp for the control output.
The output is allowed to reach maximum value (100 %) only after the
time programmed (in seconds) in the soft-start parameter has elapsed.
The Soft-start function is generally used in processes that require slow
start-up, where the instantaneous application of 100 % of the available
power to the load may cause damages to parts of the system.
In order to disable this function, the soft-start parameter must be
configured with 0 (zero).
Note:
1- This feature is available only with PID (Proportional Band greater
than zero).
2- This feature is disabed if the parameter is set to 0 (zero)
REMOTE SETPOINT
The controller can have its Setpoint value defined by an analog,
remotely generated signal. This feature is enabled through the
channels I/O3, I/O4 or I/O5 when configured as digital inputs and
configured with the function
(Remote SP selection) or through
the parameter
. The remote Setpoint input accepts the signals
0-20 mA, 4-20 mA, 0-5 V and 0-10 V.
For the signals of 0-20 and 4-20 mA, a shunt resistor of 100
is
required between terminals, as shown in Figure 4d.
LBD - LOOP BREAK DETECTION ALARM
The parameter defines a time interval, in minutes, within which the
PV is expect to react to a control output signal. If the PV does not
react properly within the time interval configured in
, the
controller interprets this as a control loop break and signals this
occurrence in the display.
A LBD event may be sent to any I/O channel. Simply configure the
function to the desired I/O channel: the selected output will be
activated when a
condition is detected. When the
parameter is programmed with 0 (zero), the
function is disabled.
The
is useful in system supervision and troubleshooting, allowing
early detection of problems in the actuator, power source or load.
KEY FUNCTIONS
Both the key digital input can be programmed to execute
functions
shown in Table 2. The key
function is configured in parameter (
key in front panel executes function 6 of Table 2:
Auto/Manual mode change. Operation of this key is enabled in
parameter
. The MAN indicator lights when the manual control
mode is selected.
EXTRA 24 VDC POWER SUPPLY – AUXILIARY P.S.
The controller provides a voltage power supply of 24 Vdc to excite
field transmitters with 25 mA current capacity. Available at the back
panel terminals 17 and 18.
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