HP 8920B, Programmer'S Manual

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Chapter 5, Advanced Operations
Increasing Measurement Throughput
Screen Display Time
Each time the screen being displayed on the Test Set (active screen) is changed, it
takes approximately 250 ms to access and draw the new screen. Additionally,
each time a field on the active screen is changed it takes a finite amount of time to
update the field. This update time is depends on the length and type of field.
When the Test Set is operated in the External Automatic Control mode it is possible to
program it to only display a special “remote screen.” When the Test Set is in this mode,
only the remote screen is displayed, regardless of the screen changes requested by the
control program running on the external controller. The remote screen mode has no affect
on the operation of the Test Set; all measurement modes, commands, and so forth, still
operate normally. The only effect is that the active screen is never changed. This saves
approximately 250 ms for every :DISPlay command in the control program and some
finite amount of time for every field update.
When the remote screen is being displayed, the Test Set’s display is in the “locked” state.
When the control program on the external controller unlocks the display, the screen is
returned to the last remote screen requested. The *RST Common Command will place the
Test Set’s display screen in the “unlocked” state. Pressing the LOCAL key causes a
locked Test Set display session to end and causes the Test Set’s display screen to return to
the unlocked state.
To Lock the Test Set’s Display Screen.
Use the :SPECial:DISPlay
'LOCKED'|'UNLOCKED' commands to lock and unlock the Test Set’s display
screen. 'LOCKED' causes the display to go to the remote screen and ignore screen
changes and other display updates thus saving time. 'UNLOCKED' causes the
display to return to the last screen requested by the remoter user. Further screen
changes and display updates take place as normal.
Syntax
:SPECiaL:DISPlay ’LOCKED’
:SPECiaL:DISPlay ’UNLOCKED’
Example
OUTPUT 714;"SPEC:DISP ’LOCKED’"
This locks the Test Set’s display screen.