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4EVAC Compact 500 quick guide
DoP OD 16.47
Author:
DD
Design revision:
2.0
Page 16 of 33
6.7.2.
EOL board
EOL boards are not supplied with the Compact 500 main unit and are available at 4EVAC as a separate
product.
4EVAC Compact 500 supports surveillance of loudspeaker lines based on a 20 kHz impedance
measurement.
For reliable impedance monitoring of the speaker line, use an EOL board. Connect the EOL board to the
end of the loudspeaker line in parallel, preferably inside the last loudspeaker on the line. The EOL is not
polarity-sensitive.
Loudspeaker line with EOL module
NOTE: The EOL module features a 145°C thermal fuse, minimizing the risk of a line short-circuit under fire
conditions. Exposing the EOL board to temperatures exceeding 145°C will damage the EOL circuit and
cause an open fault of the loudspeaker line.
The purpose of the EOL is to create a reference load at the monitoring frequency of 20kHz. With the EOL
connected, the monitoring of load impedance is more accurate and less sensitive to slow and long-term
impedance drift of the loudspeakers due to aging and weather conditions. It also gives more reliable fault
indication when a large number of loudspeakers is placed on one long line.
EOL board
NOTE: It is required to use an EOL module on every monitored loudspeaker line.
To optimally measure the loudspeaker line impedance, you can adjust the impedance of the EOL by
breaking out corners of the EOL PCB (using a tool, e.g. pliers or cutters). For the best result of impedance
measurements, use settings as described in the table below:
EOL load
setting
EOL impedance @20kHz
Normal - tip on (factory original)
320
Ω
Light - tip off
640
Ω