GW Instek GDM-398 - Manual (Page 14)

OVERVIEW
12
Functional Buttons
The table below describes what operations are performed for each of the buttons.
Button Operation Performed
LIGHT (except GDM-461) Press and hold for 2 seconds to turn the display backlight on or off.
Hold Press to enter or exit data hold mode.
BLUE Button Press to select the alternate function.
Yellow (GDM-461)
Hz% (except GDM-461)
Press the Hz% button (except GDM-461) or the Yellow button(GDM-
461) for frequency and duty cycle measurement.
RANGE  Press RANGE to enter the manual ranging mode; the Meter beeps.
 Press RANGE to step through the ranges available for the selected
function; the Meter beeps.
 Press and hold RANGE for 2 seconds to return to auto range
mode; the Meter beeps
MAX/MIN (except 461) Press to select the maximum and minimum value.
REL  Press to enter REL mode.
 Press again to exit REL mode
 For Model GDM-360/397: Press and hold for over 2 seconds to
enter or exit RS232C or USB mode* (optional).
*Note: For the GDM-461, there is no need to hold the REL
key
for 2 seconds as the RS232C/USB mode is enabled by default after
powering on.