SFRA45 User Manual
8-13
There is also an option to auto range ‘up only’ so that a
test may be carried out to find the highest range. Once the
highest range has been determined, the range can be set
to manual and the measurement made without losing any
data due to range changing. Pressing the HOME key (or
sending *TRG) restarts the auto ranging from the selected
minimum range.
When in an input channel menu, the ZERO key provides a
quick way to lock and unlock the range. When no flashing
box is visible in the input channel menu and auto ranging
is selected, pressing the ZERO key selects the range that
the instrument is currently using and sets the auto ranging
to manual, thus locking the range and preventing further
auto ranging. Pressing the ZERO key again returns to full
auto ranging from the bottom range.
For most measurement functions full auto ranging is the
most suitable option but some applications, such as where
transient events are occurring, are more reliable with
manual ranging. Manual ranging (or up-only auto ranging)
is essential for low-frequency measurements.
Scale Factor -
This option is used to compensate for an
attenuator or a scope probe. If using a X10 probe, putting
‘10’ in as the scale factor gives the correct value for
voltage. A nominal value can be entered or the attenuation
factor of the probe can be measured and the precise value
entered. The measured voltage will be displayed after
multiplication by the scale factor.
