HP 61010A Owner's Manual page 30

UPDATE * determines the moment when the input data is
read by the Digital Input. When AUTO is selected, the
input data bits are continuously monitored and the display
area in the Interactive Instrument Window is updated
accordingly. When MANUAL is selected, a START field
immediately appears under the MANUAL field (see Figure
3-2). Data is read into the Digital Input only when the
START field is selected.
When the Digital Input appears in the System View
Window, the input display will not be updated if
MANUAL update is selected. The letter "M" appears next
to the Digital Input's label in the System View Window to
remind you that it is in manual update mode. Select
AUTO update if you want the input display to update
when the Digital Input is in the System View Window.
Synchronous
Operating your Digital Input synchronously requires that
Operation
an external device signals the Digital Input to indicate that
input data is valid. After the Digital Input reads the data,
it returns a signal to the external device to indicate that it
has successfully received the information. Two control
signals — Input Data Available and Input Data Accepted
— are available at the input connector, both of which must
be connected to your external equipment (refer to Chapter
4). Once the connections are made, you are ready to
operate your Digital Input synchronously.
The front panel graphics already discussed (i.e. base, set
compl, logic sense, length, start, threshold, and update
fields) operate exactly the same way in synchronous mode
as they do in asynchronous mode. The only additional
fields that are used when operating your instrument
synchronously are the handshake and reset fields (see
Figure 3-2).
3-6 Manual Instrument Control