PPA5xx/15xx user manual
7-12
There is also an option to autorange ‘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 test carried out without losing any data
due to range changing. Pressing the TRIGGER key (or
sending *TRG) restarts the autoranging from the selected
minimum range.
In multi-phase applications, it is usual to allow the phases
to independently range but there is an option to lock the
ranges across the phases. When enabled, this means that
all the voltage channels will be on the same range and all
the current channels will be on the same 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 autoranging is
selected, pressing the ZERO key selects the range that the
instrument is currently using and sets the autoranging to
manual, thus locking the range and preventing further
autoranging. Pressing the ZERO key again returns to full
autoranging from the bottom range.
For most measurement functions full autoranging 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 autoranging)
is essential for low frequency measurements.
Separately from the current shunt and attenuator value, a
scaling factor can be entered for each channel.
In multi-phase applications, if independent ranging has
been set (see system options) then the ranging options
may be independently set on each phase. Press the R and
L keys to step between the phases.