System Manual | 2013
VAIE 2000 | Voice Alarm Integrated Systems
10
VAC 2006 • VAR 2006
UK
8.6.1
ACQuIRE IMPEdAnCE
Line impedance acquisition
Panel for acquiring and storing the impedance levels of the speaker unit
lines. This information is necessary for system initialisation and diagnostics.
8.6.1.1 Loudspeaker line impedance acquisition
Foreword
Before acquiring the impedance values, make sure that the following steps
have been completed:
• Preliminary check of the impedance of the lines using a suitable instrument
(IMPEDANCE-METER) and of the loading conditions.
• Connection of the speaker unit lines as indicated in the CONNECTIONS
Section.
The new impedance values acquired will be stored automatically in the system and shown on the labels of each zone. They are in Ohms and refer
to both lines, A and B, connected to the output of each zone. The impedance values residing in the memory will be compared by the monitoring
system with the values measured subsequently during the diagnostics routine.
note:
To measure the impedance of the speaker unit lines, the monitoring system provided in the VAC 2006 uses an inaudible 20 kHz tone. Due to the
inductance of the loudspeaker coils, the impedance at 20 kHz may be considerably different from that measured with an impedance meter, which usually
uses a 1 kHz measuring tone. The value acquired by the VAC 2006 is therefore usually indicative only as a comparative value for diagnostic purposes.
For this reason, when calculating the power absorbed by the speaker unit lines for the purpose of sizing the system it is recommended to use the value
measured with an impedance meter.
* The amplifiers of the DPU range use a tone that has a frequency of 30 Hz.
Press ESC to return to the CONFIGURATION menu.
Upon completing the procedure, carry out a MANUAL RESET of the FAILURE SIGNALLING, as described under point 8.5.3.1, page 105.
After selecting “Acquire> IMPEDANCE” from the CONFIGURATION menu, the “ACqUIRE IMPEDANCE” panel will show the impedance values
stored at the time of the previous acquisition:
•
press the oK key
8.6.2
SEt toLERAnCE
Setting the line tolerance
If the diagnostic system detects a difference between the impedance
measured in real time and the value stored in the system greater than
the tolerance that was set: an “Impedance Low” or “Impedance Hi” “Fault
Warning Condition” will be activated. For details about signalling of failures,
see the “LOUDSPk. LINE FAULT” panel (point 8.4.1, page 96).
8.6.2.1 Setting the tolerance for measuring the lines
Foreword: The measurement tolerance must be set after completing
acquisition of the line impedance
(see point 8.6.1).
The default value is 30%.
• press the numerical key corresponding to the line.
• Hold the numerical key corresponding to the zone (1-6) down,
turning the +/- knob to choose the required value.
>Valori da 10% a 100%:
tolerance above or below the stored value.
>test disabled:
Impedance check disabled. Testing for short circuits and
GND faults will in any case be carried out.
It is also possible to disable the impedance test by setting a tolerance of
0% (Not Tested).
Press ESC to return to the CONFIGURATION menu.
Upon completion of the procedure, if appropriate carry out a MANUAL
RESET OF THE FAILURE SIGNALLING as described under point
8.5.3.1,
page 105.
After selecting the “Set> IMP. TOLERANCE” option from the CONFIGURATION
menu, the “SET TOLERANCE” panel will show the current tolerance settings
for each output zone.
