Tesira Operation Manual
11. Operation and performance
D SERIES Tesira Operation Manual rev 1.0.0
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protect the channel. The CAL should not be activated in normal usage. If activated, this is shown by amber or red
indication on the Amp LED of the affected output channel and a corresponding text description in Tesira and CAFÉ
software programs. Refer to Section 14.1 for more information on warnings and faults
11.3.7. Voltage Clip Limiter (VCL)
If current draw from the unit’s power supply is too high, the PSU’s regulation capability may be exceeded and
the internal voltage rails may drop and cause clipping. If this occurs, the VCL acts rapidly to prevent clipping on
the subsequent peaks. Limiting is performed by the ISVPL limiter in conjunction with the selected ISVPL prole.
Indication of this condition is shown on the output LEDs. Refer to Section 14.1 for more information on warnings
and faults.
11.3.8. Temperature Protection
11.3.8.1. Overview
D Series devices are equipped with a sophisticated temperature sensing system that provides protection
from overheating which may occur as a result of inadequate ventilation or excessive power output. Thermal
measurements are made at several points within each power output channel along with measurements in the
power supply and DSP areas. The temperature protection scheme is designed to let the amplier to operate
continuously, with the highest possible output, and prevent shutting down. If temperature in any area reaches
a critical level, a warning is displayed. The warning is issued at approximately 80% of the maximum allowable
temperature. If the temperature continues to increase, a limiter is engaged that limits signal peaks to reduce further
heat accumulation. Limiting is accomplished by gradual reduction of the ISVPL thresholds. In the extreme case
where the limiter cannot reduce heat accumulation and temperature reaches a dangerous level, a fault is displayed
and audio is muted.
Each power output channel, the power supply, and DSP area have separate indications. For all temperature faults,
temperature monitoring will continue at 0.5 second intervals, with the output remaining muted. When the area has
cooled below the dangerous threshold, the fault condition is cleared and audio is restored.
11.3.8.2. Power Output Channels
A power output channel temperature warning or fault is indicated by the Amp LED for that channel.
• A warning is indicated by a static amber LED
• Amplier Temperature Limit (ATL) is indicated by an amber LED
• A fault is indicated with a static red LED
An event report is sent to the Tesira software for both the warning and the fault. If a temperature fault condition
arises on a power channel, the output of that channel will be muted.
When an amplier output channel reaches the temperature warning threshold, the Amp channel Temperature
Limiter (ATL) is engaged, reducing power output to avoid amp channel protection (muting). Limiting is removed
when temperature falls below the warning threshold.