National Instruments BridgeVIEW Manual De Usuario

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Chapter 11
Loops and Charts
11-10
© National Instruments Corporation
Wait Until Next ms Multiple function (Functions»Time & Dialog)— 
Multiply the knob terminal by 1,000 to convert the knob value in 
seconds to milliseconds. Use this value as the input to the Wait Until 
Next ms Multiple function. 
Multiply function (Functions»Numeric)—The multiply function 
multiplies the knob value by 1000 to convert seconds to milliseconds.
Numeric constant (Functions»Numeric)—The numeric constant 
holds the constant by which you must multiply the knob value to get a 
quantity in milliseconds. Thus, if the knob has a value of 1.0, the loop 
executes once every 1000 milliseconds (once per second).
3.
Run the VI. Rotate the knob to get different values for the loop delay. 
Notice the effects of the loop delay on the update of the 
Random 
Signal
 display.
4.
Save the VI as 
Random Signal with Delay.vi
 in the 
BridgeVIEW\Activity
 directory. Close the VI. 
End of Activity 11-4.
Preventing Code Execution in the First Iteration
The While Loop always executes at least once, because G performs the 
loop test for continuation after the diagram executes. You can construct 
a While Loop that pretests its conditional terminal by including a Case 
structure inside the loop. Wire a Boolean input to the Case structure 
selector terminal so the subdiagram for the FALSE condition executes if 
the code in the While Loop should not execute. See Chapter 12, 
 for more information about 
using Case structures.