Lab.gruppen PLM 20000Q - Manual (Page 28)

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Operation and Performance
PLM Series Operation Manual rev 1.2.3
5.3.6 Current Average Limiter (CAL ™ )
The Current Average Limiter (CAL) monitors the RMS current drawn from each power output channel
to ensure that the power output stages are not overloaded. When activated, it regulates the current to a
safe level to protect the channel. The CAL should not be activated in normal usage, but if it is, its opera-
tion is indicated by an active LED and the message CAL ACTIVE. Further indication is given within the
Lake Controller software.
5.3.7 Voltage Clip Limiter (VCL)
If current draw from the PLM’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 clip-
ping on the subsequent peaks. Limiting is performed by the ISVPL limiter in conjunction with the selected
ISVPL profile. Indication of this condition is shown on the output LEDs.
5.3.8 Temperature Protection
5.3.8.1 Overview
PLM 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 measure-
ments in the power supply and DSP areas. If temperature in any area reaches a critical level then a warning
is displayed and gain reduction is applied. If the temperature continues to increase and reaches a dangerous
level then 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.
5.3.8.2 Power Output Channels
A power output channel temperature warning or fault is indicated in one of the front panels LEDs (in the
right-hand soft function buttons).
▸ A warning is indicated by a static yellow LED and adjacent warning message: TEMP WARN:CH
▸ A fault is indicated with a static red LED and adjacent warning message: TEMP FLT:CH
An event report is sent to the Lake Controller 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.