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4.2.10 LOOP BREAK DETECTION (LBD) FUNCTION
The
Loop Break Detection
function (
CFG
>>
ALM
>>
Lbd.t
) allows you to set a maximum time interval (in minutes) for the PV to react to the
control output command. If the PV does not react minimally and adequately within this interval,
N20K48 Modular Controller
signals the
occurrence of an LBD event on its display (i.e., problems in the control loop).
You can also address the LBD event to one of the controller alarms. To do this, simply set the desired alarm with the
LDB
function. When
the configured event occurs (
CFG
>>
ALM
>>
Fu.A1
,
Fu.A2
,
Fu.A3
or
Fu.A4
>>
Lbd
), the respective output will be activated (see
section).
This function is disabled if configured with 0 (zero).
This function allows the device to detect problems in the installation, such as a defective actuator, a failure in the load power supply, or
an open sensor. Even in these cases, the
Lbd
function will signal the occurrence of an LBD event after the time interval you have set
has elapsed.
4.2.11 SAFE OUTPUT FUNCTION IN CASE OF SENSOR FAILURE
With this function, the control output will enter a safe condition for the process whenever there is an error at the input (sensor). When
identifying a failure, the controller will apply to MV the percentage value that was set in the
IE.ou
parameter (
CFG
>>
CtRL
).
If the
IE.ou
parameter has been set to 0.0 (zero), this function will be disabled, and the control output will be switched off whenever
occurs a failure at the input.
4.2.12 TIMERS
The controller has 2 timers (
T1
and
T2
), which operate independently of the process control. The parameters that define the operating
mode of these timers are listed in the Timer Cycle (
CFG
>>
TM
). Any of the controller outputs can be linked to the timers.
Time counting always starts from T1. The device starts counting from T2 at the end of this count.
In parameter
T.tb
you can define whether the time base will be in HH:MM (hours and minutes) or in MM:SS (minutes and
seconds). The parameter
T.RUN
allows the process control to be disabled at the end of the timers.
The flags T1 and T2 are displayed on the front of the controller and refer to the status of the T1 and T2 timers (see
section).
T1 TIMER
T1 is the main timer. You can define its operation by setting 2 parameters:
t.str
Timer trigger mode
t.end
Output behavior during timer process
If you set parameter
T1.e
, T1 parameter will be displayed in the Operation Cycle.
T1 TIMER TRIGGER
You can set Timer 1 in parameter
t.str
:
T.str
Timer Start
Allows you to set
T1
timer start/stop mode.
oFF
Timers are off (T1 and T2). The parameters related to the timer will not
be displayed.
SP
Starts counting T1 when the PV value reaches the SP
value defined for the process.
F
Starts counting T1 by pressing the
key.
Once the timer has started, you can interrupt it by briefly pressing the
key (1 s). Another short
press will resume the timer. A long press of the
key (3 s) immediately ends the timer cycle in
progress.
RUN
Starts counting when control is enabled (
RUN
>>
YES
).
Di
Triggers with digital input.
The control must be enabled (
RUN
=
YES
) before you can trigger the timer by pressing the
key.
OUTPUT T1 BEHAVIOR DURING T1
The output T1 can behave in 2 ways during T1 timer:
T.end
Timer End
T1
output behavior at the end of
T1
timer.
on
T1 output is
on
(
on
) at the end of T1. At the start of T1 timer, the T1 output remains off. At the
end of the timer, the T1 output is on and remains in this condition until a new cycle starts.
The T1 flag flashes during T1 timer. It switches on permanently after T1 has elapsed, indicating
that the output is still on.
off
T1 output is
off
(
off
) at the end of T1 interval.
In this mode, T1 is on when T1 timer starts, and is off at the end
of T1 timer. The T1 flag flashes during T1 timer and definitively
switches off at the end of T1.
On the controller front panel, the
T1
flag indicates the timer status.
In both cases, the respective flag (T1 or T2) will flash rapidly whenever the timer is interrupted by pressing the key
.
