National Instruments BridgeVIEW ユーザーズマニュアル

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Chapter 11
Loops and Charts
11-8
© National Instruments Corporation
a check mark in a dialog box; it becomes highlighted but does not change 
until you release the mouse button. 
Switch Until Released action —Changes the control value when you click 
on the control. It retains the new value until you release the mouse button, 
at which time the control reverts to its original value. The action is similar 
to that of a doorbell, and is not affected by how often the VI reads the 
control.
Latch When Pressed action—Changes the control value when you click on 
the control. It retains the new value until the VI reads it once, at which point 
the control reverts to its default value. (This action happens regardless of 
whether you continue to press the mouse button.) This action is similar to 
that of a circuit breaker and is useful for stopping While Loops or having 
the VI do something only once each time you set the control. 
Latch When Released action— Changes the control value only after you 
release the mouse button. When your VI reads the value once, the control 
reverts to the old value. This action guarantees at least one new value. As 
with Switch When Released, this action is similar to the behavior of buttons 
in a dialog box; clicking on this action highlights the button, and releasing 
the mouse button latches a reading.
Latch Until Released action —Changes the control value when you click on 
the control. It retains the value until your VI reads the value once or until 
you release the mouse button, depending on which one occurs last.
Activity 11-3. Change the Mechanical Action 
of a Boolean Switch
Your objective is to experiment with the different mechanical actions of 
Boolean switches.
1.
Open the 
Random Signal.vi
, as saved in Activity 11-2, from the 
BridgeVIEW\Activity
 directory. The default value of the 
Enable
 
switch is FALSE.
2.
Modify the vertical switch so it is used only to stop the VI. Change the 
switch so that you do not need to turn on the switch each time you run 
the VI.
a.
Turn on the vertical switch with the Operating tool.