Selecting The Digital Output - HP 61010A Owner's Manual

sent, and IDAV must be set low for a minimum of
10/js.
The status register on the Digital I/O indicates that the
Digital Input is now busy reading data. When the Digital
Input sets ID AC low, IDAV can go high again at any time
as long as the minimum pulse width requirement has been
satisfied. When the Digital Input has accepted the input
data, the status register changes state and IDAC is set
high again. This signals the external device that the
Digital Input is ready for another data transaction.
If a second high-to-Iow transition of IDAV is encountered
during the time that IDAC is being pulled low, a message
on the Soft Front Panel will alert you to the fact that your
input data was "overrun", that is, changing faster than
the computer can accept it. This means that your input
data was changed before it had been completely read into
the computer from the Digital Input,
Selecting the
Digital Output
If the Digital Output is not already displayed in the
Interactive Instrument Window, point to and select its
label in the System View window',
Figure 3-4 shows the factory default settings that appear
when the first Digital Output in your PC Instruments
System is selected. These defaults are: decimal base, 16 bit
length, 0 start bit, TTL driver, positive logic sense,
handshake and output disabled. The default label
(DIG.OUT.01) appears in the upper right corner of the
Interactive Instrument Window. The Interactive Instrument
Window can display either the front panel or rear panel of
the Digital Output. Use the FRONT PANEL softkey to
display the front panel. This is the panel that lets you
operate your instrument. If the front panel that appears on
your computer's display does not look like Figure 3-4, it
means that a previous user has changed the default
settings.
Manual Instrument Control 3-9