6
amplitude is 100 mV, the maximum amplitude
is 4.00 VDC, and outputs outside the range of -3
to +4 VDC are not allowed.
AB and CD OUTPUTS
The menus for the AB and CD outputs are
similar to the other outputs. Example menus for
the AB output are shown on the following page:
AB&-AB Loads = High Z
AB: TTL NIM ECL VAR
AB:Amplitude = +1.00V (if VARiable is
selected)
AB:Offset= +0.50V (if VARiable is selected)
The cursor (up/down) keys select the load
impedance for both the AB and -AB outputs. It
is very important that if a 50
Ω
load is specified,
that a 50
Ω
load be present on BOTH the AB
and the -AB output BNC's.
The cursor (left/right) keys select the logic
levels for the AB and -AB outputs. If TTL, NIM
or ECL is selected, then no further submenus are
needed to specify the outputs: both the
"Normal" and "Inverted" logic levels are
available at separate front panel BNC's. If VAR
is selected, then the next two submenus are used
to set the amplitude and offset of the outputs.
GPIB MENUS
There are three menus which are accessed by the
GPIB key. They are:
Data:_______________
GPIB Address: 15
Service RQST: (EXC)
The first menu displays the last 15 characters of data
that have been received over the GPIB. 256
characters are retained in memory and may be
viewed by scrolling the display window with the
cursor keys. Spaces and control codes will not be
displayed, however special characters for carriage
returns and line feeds will be displayed. This feature
is very useful when debugging computer programs
that control the DG535.
The GPIB address may be set in the second menu.
The keypad is automatically placed in the numeric
mode for this menu item. Any address from 1 to 30
may be entered: the default address for this
instrument is 15.
The third menu allows the user to generate a service
request by pressing the EXC button (lower right on
the front panel). A service request is used to attract
the attention of the GPIB controller.
