Serial communication blocks my while loop

[Oxydroid]

Hi everyone. I need your help with my program. I am using LabView2014 and an Agilent B2902A.
I want to measure current value with my instrument continuously, store values every second and display messages received through the serial port when I get some. 
Everything works perfectly separately but when I put everything together I have this problem: my instrument is waiting for a message from the serial port to take (and display) a measure. 
Do you have any idea to save my problem? 
Thank you ! 

Pauline

(Please find attached a screenshot of my program)

[Albert.Geven · Accepted solution]

Use bytes at serial port to check if a message is available and only read when a message is available.

[Oxydroid]

@Albert.Geven, thanks for the fast reply. 

I don't know how to test if there is a message before reading. Could you give me more details to do it? 

[crossrulz · Accepted solution]

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@Oxydroid wrote:

@Albert.Geven, thanks for the fast reply. 

I don't know how to test if there is a message before reading. Could you give me more details to do it? 

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Use the Bytes At Port property and test to see if there are more than 0 bytes available (Greater Than 0?).  Use a case structure to conditionally read the serial port.

[Oxydroid]

@crossrulz and Albert.Geven

I tried it as you can see on the new screenshot attached to this message but it is not working better... Maybe I did it wrong? 

[nyc_(is_out_of_here)]

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@Oxydroid wrote:

@crossrulz and Albert.Geven

I tried it as you can see on the new screenshot attached to this message but it is not working better... Maybe I did it wrong? 

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Post your VI not a screenshot

[Dennis_Knutson]

What is your second instrument and how is its reading related to the 2902? How many bytes are you trying to read?

[Albert.Geven]

You only should read when bytes at port>= bytes to read

because if the message is not completely available it will block the other process

And indeed don't send pictures but the vi then we can eventually update it in a correct way

[crossrulz]

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@Albert.Geven wrote:

You only should read when bytes at port>= bytes to read

because if the message is not completely available it will block the other process

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My thought on that is that if there is data there, the rest of the message will be there shortly.  There may be a brief blocking, but not likely enough to matter, depending on how long your message really is.

[Oxydroid]

Thanks to all of you, I solved my problem. First, it was what you said (test to read only if there is a message available) and then it was that my excel file was full (I guess so because it didn't want to store my variables anymore and block the all process).
Next time, I will send the VI and not screenshot as you asked.