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5.6.2.
HB alarm
This type of alarm calls for the use of the current transformer
input (I.CT1 / I.CT2), which is assigned to a control output,
from which the ON and OFF phases are considered.
The alarm signals changes in load draw, discriminating the
value of currents for current inputs I.CT1 and I.CT2.
The alarm is active if the rms current value:
•
is below set value LOW.ON in the ON time of the of the
assigned control output,
•
is above set value HIG.ON in the ON time of the of the
assigned control output,
•
is above set value HI.OFF in the OFF time of the of the
assigned control output.
Single tests are disabled by setting a value of "0.0".
The HB alarm trips if one of the above setpoints is exceeded
for the set TIME.
Each of the three conditions may indicate a problem in the
process managed by the assigned control output.
HB alarm tests are activated only with ON times of the
assigned output longer than 0.4 seconds.
The alarm resets automatically if the condition that caused
it is eliminated.
5.6.3.
The load current is shown by parameters CURR1
and CURR2 on the user configuration menu..
Note: ON/OFF times refer to the cycle time set for the con-
trol output selected in OUT.
During configuration, you have to indicate load type with
LoAd, specifying if it is a monophase load with only one
current transformer CT1 (MONO), a 3-phase star load no
neutre with CT1 and CT2 (STAR), or a 3-phase delta load
with CT1 and CT2 (DELTA).
~
~
SSR
+
-
+
-
Out
logic
Figure 21 - HB alarm with monophase load
CT
In
CT1
Controller
80209C_MHW_850-1650-1850_01-2020_ENG_pag. 201
~
SSR
+
-
CT
~
SSR
+
-
~
+
-
Out
In
logic
CT1
Controller
Figure 22 - AHB alarm with 3-phase star load without Neutral
~
~
SSR
+
-
~
SSR
+
-
+
-
Out
logic
Figure 23 - HB alarm with 3-phase delta load
A 3-phase load can be controlled by means of a logic out-
put connected in series to two SSR modules.
HB alarm calibration
Calibration is possible:
- using U.CAL = AL.HB user calibration (with output selected
in OUT 100% on)
- as a function of the settable front key (but.1 for model 850,
but.1 or but.2 or but.3 for models 1650 and 1850): to acquire
the current value, the automatic or manual power must be
> 10%; press the key to confirm the current forcent value (set
in parameter THR.PE) that is saved in parameter LOW ON.
5.6.4.
LBA alarm
This alarm signals an interrupt in the control loop as a pos-
sible consequence of a sensor in short circuit, an inverted
sensor, or a load break.
It trips an alarm if the variable does not increase its value in
heating (or does not decrease it in cooling) when maximum
power is supplied for settable time LBA.TM.
LBA alarm in the presence of ON-OFF control (of heating,
cooling and heating, and heating/cooling).
In the presence of PID control with ON-OFF heating or
cooling, LBA.PW can only be set for the PID part.
CT
In
CT2
CT
Load
CT
In
In
CT1
CT2
Controller
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