Teledyne LeCroy AP033 - Manual (Page 19)

Operator’s Manual
922260-00 Rev A 13
With oscilloscope software versions 7.6.0 and higher, the probe gain, internal attenuation, and
offset can be conveniently controlled through the oscilloscope’s user interface. The common mode
range is also displayed. Manual control through the oscilloscope user interface can be found in the
COUPLING menu or the Channel dialog of the channel to which the probe is connected. The
appearance and functionality of the control menu has changed with incremental versions of the
oscilloscope software.
With software versions 8.1.0 and higher, there are two modes of gain control: Auto and Manual.
The oscilloscope defaults to Auto mode when the probe is first attached. In Auto mode, the
VOLTS/DIV knob controls the oscilloscope’s scale factor, AP033 gain, and AP033 attenuation to give
the full available dynamic range: 200 μV/div to 1 V/div (without external attenuator), or 2 mV/div
to 10 V/div (with external

÷

attenuator installed). Some of the transitions in scale factor will
result in a change of the attenuation in the AP033 probe. The common mode range, input
capacitance, and noise level of the probe will change with the probe attenuator setting. For
Volts/Div settings which can be produced with more than one combination of probe gain and
attenuation settings, Auto mode selects the combination which results in greater common mode
range and lower input capacitance.
In some situations, you may wish to select probe settings optimized for the lowest noise
performance with lower common mode range. Likewise, you may require that the probe not
change input capacitance, noise, or common mode range as you change the VOLTS/DIV setting.
These requirements can be met by setting the probe to Manual gain control mode. When set to
Manual mode, the dynamic range of the VOLTS/DIV knob is limited to the scale factors that can be
obtained without changing the AP033 gain or attenuation. Thus in Manual gain control mode, only
the scale factor of the oscilloscope will be changed. In this mode, dedicated menu boxes are
displayed for Probe Attenuation and Probe Gain. (Refer to Figure 3). The available values that
appear in the Probe Atten menu box will change depending on the presence of the external
attenuator. When the external ÷10 attenuator is not installed, ÷10 and ÷1 will be displayed. With
the external ÷10 attenuator, only ÷100 will be displayed. In software versions 8.1.0 and higher, the
channel OFFSET knob will control the probe offset, rather than the offset at the oscilloscope input.
The OFFSET buttons on the probe body are disabled.
The Coupling Menu refers to the probe input. The common mode dynamic range (CMDR) for the
selected probe gain and attenuation settings are displayed in the Probe Attenuation menu In some
versions of software, the input capacitance from each input to ground is also displayed.
When using the AP033 with the ADPPS power supply on oscilloscopes without a ProBus interface,
use Table 2 to select the desired effective volts per division scaling.