open and close visa inside a while loop

[sam009]

Hi,

I need to read a position from a control unit device continuously or even by click a button, for this I have to put "visa configure serial port" and" "visa close" inside a while loop. Dose it make any problem?

[RavensFan]

It could slow down your code.  It could cause you to miss bytes while the port is closed depending on how you are handling the serial communication overall.

Why do you "have to put" them in the loop?

 It might work just fine, or it might cause problems.  I wouldn't recommend it.

[sam009]

Thanks for reply,

If I don't put inside the loop, the position reading comes with delay and I have to click several time the button to shows the correct value!!!

[RavensFan]

Then something must be wrong with your code.

You need to post your VI so we can look at it.

[JÞB]

Sounds like a "Flush buffer" before each read is needed to get rid of "Old" data being "Spewed Asynchronously" from the device on the other end.

What is the device? (Make/Model)

[sam009]

The programs are attached for continues reading and by clicking. 

The device is a Control unit for antenna.

[sam009]

Sorry...It seems the attachments are not readable I will attaché them again.

[Yamaeda]

Attach the .vi, not pictures.

/Y

[sam009]

I attached the vi,

[crossrulz]

You shouldn't need the VISA Event nodes.  Get rid of those.

Why are you using Concatinate String just to build up a constant.  Just create a single string constant.  It is a lot cleaner.

Is the antenna constantly sending data to you or only when you request it?