Lab.gruppen PLM 20000Q - Manual (Page 61)

Front Panel Interface
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PLM Series Operation Manual rev 1.2.3
To change the Iso-Float setting, adjust the value using the rotary encoder. The current settings are also
displayed on the front panel I/O STATUS screen.
The analog inputs utilize Iso-Float transformerless electronic balancing circuitry. This provides electrical
isolation from an analog source comparable to that achieved with transformer-based designs. However, pin
1 of the XLR input connector may be connected to ground within the PLM if desired. This option is selected
by using the rotary encoder to toggle between FLOATING and GROUNDED.
It may be necessary to change this setting to resolve ground loop problems when using analog inputs.
7.11.4 Attenuation Submenu
MENU > ATTENUATION
Figure 7-16: Attenuation Menu
The default setting of 0.00 dB (i.e. no attenuation) is adjustable in 0.25 dB increments down to -100 dB.
Adjustment of attenuation at the input to the PLM power stage is available on a per-channel basis. This
adjustment is the PLM equivalent of a conventional amplifier level control. The power output channels may
be turned down using these parameters before powering on or off. Please refer to the signal flow diagram
in Figure 6-2 on page 27.
By default, all channels are deselected. Press the SEL ALL button to select/deselect all channels (as shown
in Figure 7-16) or, press a single button on the right to adjust a channel individually.
For 4-channel PLMs, only ONE channel or ALL
channels may be adjusted. It is not possible to
adjust only two or three channels.