Lab.gruppen C Series 88:4 - Manual (Page 25)

5. Operation and Performance
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C Series C 88:4, C 68:4, C 48:4, C 28:4 and C 16:4 Operation Manual rev 2.2.3
5.4.7 Output Current Peak Limiter (CPL)
The Current Peak Limiter (CPL) ensures that the amplifier will not be damaged by trying to deliver current to the
outputs exceeding the physical limits of the transistors. The CPL keeps the amplifier within the Safe Operating
Area. The CPL is non-adjustable and has different limit values depending on model type. The maximum output
current values for the four C Series models are:
▸ C 88:4, 35.5 Arms per channel
▸ C 68:4, 24.5 Arms per channel
▸ C 48:4, 17.5 Arms per channel
▸ C 28:4, 12 Arms per channel
▸ C 16:4, 8.5 Arms per channel
CPL activity is indicated by illumination of an orange LED for each channel on the front-panel. Warnings also
are shown in the DeviceControl software’s GUI.
A steadily illuminated orange CPL LED indicates a short circuit situation (or very low impedance). The output
will mute for 6 seconds before measuring the output impedance again. This will continue until the short circuit
is fixed, at which time the output will automatically un-mute. An input signal must be present to allow detection
of short circuit or low- impedance conditions.
If the CPL LED is steadily illuminated orange while the output
is muted and the -4 dB signal LED is NOT on, then the
amplifier output is detecting a short circuit or low impedance
condition. The problem can be solved by checking input and
output cables and examining the state of the loudspeaker
load. If there is no short circuit present, then the condition may be rectified
by lowering the VPL or input levels.
If the CPL and -4 dB indicators are lit simultaneously, then the amplifier is delivering excessive current and is
being forced into a current limiting state (output muted).