Device Description HG G-31500-A | English, Revision 02 | Date: 10.06.2021
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Chapter 4 – Audio Control: Interfaces, Telegrams & Buttons
4
Audio Control: Interfaces, Telegrams &
Buttons
4.1 Audio Files on the USB Storage Medium
The audio files are read from a USB storage medium and must be in MP3 or WAV
format. A maximum of 255 files can be managed, which must be located in the root
directory of the USB storage medium. Subdirectories are not supported. The files are
sorted in ascending alphabetical order.
For a more convenient overview, the file name can be preceded by an index:
Figure 4
Example: File names with index for easier assignment
001_FileName1.mp3
002_FileName2.mp3
003_FileName3.mp3
…
Thus, the index would also correspond to the audio file number used when con
-
trolling the audio player.
To unify the volume of all audio files, it is recommended to normalize the files with
a program such as
mp3gain
®.
https://sourceforge.net/projects/mp3gain/
Furthermore, pauses at the beginning of the audio files should be removed to avoid
unnecessary delays during playback. A suitable program for this purpose would be
e.g.
Audacity
®.
4.2 Digital Inputs
With active digital inputs, control via telegrams (serial/CAN) is not possible.
Five digital inputs are available. The digital inputs are active when a voltage in the
range of +5 volts to +30 volts is applied. For deactivation, the voltage must be in the
range of 0 volts to +1 volts.
The first five audio files are selected directly from the respective digital input and are
played as long as the digital input is active. If several digital inputs are activated, the
first recognized digital input remains valid until it is released again. Only then are the
other digital inputs processed. The playback takes place with maximum volume
(100%), whereby the limitation is carried out by the potentiometer.
