Lab.gruppen PLM 20K44 - Manual (Page 36)

7. Front Panel Interface
36
PLM+ SERIES Operation Manual rev 1.0.0
7.8.5. LED Fault, Warning and Clip Indication B D
A tricolor LED is embedded inside each of the eight dynamic function buttons. These convey a variety of status
indications including faults and warnings, signal clip indications, Module input mute, Module output mute and
Power Output mute. Table 7.4 summarizes the meaning of the LED indications.
Table 7.4: LED Fault and Warning Indications
Note: An unlit output LED indicates either the channel is not available for the model in use, or that the
power output channel is not routed to a Module output channel.
7.8.5.1. Clip Indication
The front panel LEDs also indicate input and output clip or pre-clip conditions that can occur within the PLM+.
Input Clip
Input clipping is monitored at two stages in the signal path:
• Analog Input Stage: If the input signal exceeds either +26 dBu, a clip indication is displayed.
• A warning is displayed at +24 dBu (i.e. 2 dB from Clip)
• Module Input Stage: If the signal level at this point exceeds +21 dBu, a clip indication is displayed.
Input clipping is indicated by the affected Module LED flashing red and INPUT CLIP displayed on the LCD. If a
subsequent input clip within 400 ms is detected, the LED remains lit for a longer period.
Output Clip
All output channels are monitored by a suite of protection circuits that include a Current Peak Limiter (CPL) and an
Inter-Sample Voltage Peak Limiter (ISVPL).
The ISVPL will indicate clip only when exceeding the amplifier’s maximum output voltage. If the ISVPL is set so as
to limit the output below maximum voltage, then clip indication will not occur when reaching the ISVPL threshold.
Please refer to section 5.3 for further information.
If CPL protection is active, or a voltage clip occurs, then the associated Power Output Channel LED will flash red
and a text warning will be displayed on the screen.
LED Color Indication
Green Status Good / Unmuted
Yellow Warning
Red Fault / Muted
Flashing Red Clip