Liebherr WKt 4552 GrandCru - Manual (Page 7)

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Normal operation Alarm condition
e.g. green lamp
indicating normal
opretaion
external power supply
e.g. red lamp
indicating alarm
condition
external power supply
N.O.
COM
N.C.
N.O.
COM
N.C.
Alarm condition
Normal operation
Open or close A1– 6 to GND
Alarm inputs A1– 6
Any contractors
normally open or closed
GND GND
GND
GND
A1 A2 A3 A4 A5 A6
COM
COM
N.O.
N.C.
External alarm contact connection
LKPv and LGPv laboratory appliances with Profi-Controller
Example: GSM dialler alarm system using volt free alarm contact
Alternatively, if no internal warning system is in place and additional wiring inside the building is problematical, the volt-free contact can be used in conjunction
with e.g. a GSM alarm dialler. There are many different versions of GSM alarm dialers available on the market which either call a telephone number and/or send
a text message in case of an alarm. Depending on the specification of the alarm dialler, potentially many appliances can be connected to one dialler. Being GSM
appliances, only a SIM card and a power supply are required.
The following example shows a circuit with a GSM dialler: A change in relay setting activates the alarm function of the dialler and thus initiates either a telephone
call or an SMS to pre-defined numbers with a pre-recorded message. The dialler in the example has 6 addressed alarm inputs. This could be 6 individual appliances
or 6 rooms, each with several appliances wired in series.
Volt-free contact
All LKPv and LGPv models have an integrated volt-free contact. The relay contact can be wired into a warning system in the building which would advise e.g. security
personnel or a janitor outside of working hours. Warning systems with audio or visual alarms are possible.
The following example shows a circuit with a visual alarm. Either normal operation or alarm condition or both can be indicated. Either AC or DC circuits are possible,
max AC 230 V / 5 Amp.
Example: visual alarm system using volt free alarm contact
In spite of all efforts to produce appliances of unequalled reliability, Liebherr strongly recommends that the volt-free contact is wired into some kind of independent
and external warning system. Please take a few moments to consider the value of the contents of the refrigerators and freezers under your supervision. The cost
of such a warning system is often negligible in comparison to the value of the contents.