N1200HC Controller
NOVUS AUTOMATION
3/12
For a negative SPA1 value, the Differential alarm triggers when the
value of PV is
within
the range defined above.
•
difl
– Alarm of Minimum Differential Value
It triggers when the value of PV is
below
the defined point by:
(SP – SPA1)
Using the Alarm 1 as example.
•
difk
– Alarm of Maximum Differential Value
Triggers when the value of PV is above the defined point by:
(SP + SPA1)
Using the Alarm 1 as example.
SCREEN
TYPE
ACTUATION
Off
Inoperative
Output is not used as alarm.
Ierr
Open sensor
(
i
nput
Err
or)
Activated when the input signal of PV is
interrupted, out of the range limits or Pt100
in short-circuit.
Rs
Event (
r
amp and
S
oak)
Activated in a specific segment of program.
Lo
Minimum value
(
Lo
w)
SPAn
PV
Ki
Maximum value
(
Hi
gh)
SPAn
PV
Dif
Differential
(
diF
erential)
SP
PV
SP + SPAn
SP - SPAn
SP
PV
SP - SPAn
SP + SPAn
Positive SPAn
Negative SPAn
Difl
Minimum
Differential
(
diF
erential
L
ow)
Positive SPAn Negative SPAn
SP
PV
SP - SPAn
SP
PV
SP - SPAn
Difk
Maximum
differential
(
diF
erential
H
igh)
SP
PV
SP + SPAn
SP
PV
SP + SPAn
Positive SPAn
Negative SPAn
Table 3
– Alarm functions
Where SPAn refers to Setpoints of Alarm
SPA1
,
SPA2
,
SPA3
and
SPA4
.
ALARM TIMER MODES
The controller alarms can be configured to perform 3 timer modes:
•
One pulse with defined duration;
•
Delayed activation;
•
Repetitive pulses.
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
A1t1
,
A1t2
,
A2t1
,
A2t2
,
A3t1
,
A3t2
,
A4t1
and
A4t2
.
OPERATION
t 1
t 2
ACTION
Normal
Operation
0
0
Alarm Event
Alarm
Output
Activation for a
defined time 1 to 6500 s
0
Alarm Event
Alarm
Output
T1
Activation with
delay
0
1 to 6500 s
Alarm Event
Alarm
Output
T2
Intermittent
Activation 1 to 6500 s 1 to 6500 s
Alarm Event
Alarm
Output
T1
T2
T1
Table 4
- Temporization Functions for the Alarms
The leds associated with the alarm light up when an alarm condition
exists regardless of the status of the alarm output.
INITIAL BLOCKING OF ALARM
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 enabled only after the occurrence of a non-alarm
condition followed by a new occurrence for the alarm.
The initial blocking is useful, for instance, when one of the alarms is
configured as a minimum value alarm, causing the activation of the
alarm soon upon the process start-up, an occurrence that may be
undesirable.
The initial blocking is disabled for the sensor break alarm function.
CONTROL MODE
The controller can operate in two different manners: Automatic mode
or Manual mode. In automatic mode the controller defines the
amount of power to be applied on the process, based on defined
parameters (SP, PID, etc.). In the manual mode the user himself
defines this amount of power. The parameter
(trl
defines the
control mode to be adopted.
PID AUTOMATIC MODE
For the Automatic mode, there are two different strategies of control:
PID control and ON/OFF control.
The PID control, available only for the
Control 1
, has its action
based on a control algorithm that works on the basis of the deviation
of PV relative to SP, based on
Pb
,
Ir
and
Dt
setting parameters.
The Control 2 has only Proportional (
Pb
) action.
On the other hand, the ON/OFF control (obtained when Pb=0)
operates with 0 % or 100 % of power, when PV deviates from SP.
The determination of the PID parameters (
Pb
,
Ir
and
Dt
) is
described in the item DETERMINATION OF PID PARAMETERS of
this manual.
CONTROL 2
A second independent control output (control output 2) may be used.
This output, with only proportional action is typically used in the
cooling process where the heating is controlled by the control output
1.
In case the application requires simultaneous heating and cooling,
you must configure the
Act
=
re
and adjust the parameters (
OLAP
)
overlap to define the type of operation.
There are three cases:
OLAP
> 0; when there are overlapping activities of power between
heating and cooling.
Control Output
Process Variable
Overlap
Pb1
Pb2
Output 1
Output 2
Set Point
OLAP
< 0; when there is a dead zone of power actuation between
heating and cooling.
Control Output
Process Variable
Dead Zone
Pb1
Pb2
Output 1
Output 2
Set Point
OLAP
= 0; When there is no overlap or dead zone. At the point
where the PV reaches the SP there is no actuation of any output.
Control Output
Process Variable
Pb1
Pb2
Output 1
Output 2
Set Point