Instrument Control (GPIB, Serial, VISA, IVI)

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visa read buffer

I have a VI to read a serial port, the probleme I am waiting for 2 Byte, but with my VI I can use only one Byte.
How can I save the 2 Byte in one string to compare it with another string.
 
Thanks
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Message 1 of 9
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I change  my VI and if I send first byte and wait and send the second byte its working, but if I sent the 2 bytes together it doesnt work
how can I recieve the 2 byte (^Q = serial port is open) ?
 
thanky
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Message 2 of 9
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You did not use shift register like I suggested in your other post. Try the attached modification. Whatever data is returned, is added to the previous data and then a search is made of all data.

A shift register is a basic element in LabVIEW and you should be familiar with their use. It seems like you are just starting out and might find the tutorials at http://www.ni.com/academic/lv_training/how_learn_lv.htm of some benefit.

Message 3 of 9
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thank you for your help.
when I send   ^ alone I recieve it, when I send Q alone I recieve it, but when I send both together "^Q) I recieve a squar.
maybe Labview understand ^Q not like 2 caracter but like a command.
 
I dont andersant Smiley Sad
 
in this image I send first ^Q together then Q alone rhe ^ alone then ^Q together
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Message 4 of 9
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The square is an unprintable character. I asked you before and you did not answer - are you just sending the '^' character (shift 6) or are you hitting the CTRL key? The ^Q in your search string is the correct way at all to look for a CTRL-Q


Message Edited by Dennis Knutson on 07-30-2008 08:41 AM
Message 5 of 9
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th ^ is on my keboard, I type the ^ and type any caractere then I delete the caractere so I can having the ^.


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Message 6 of 9
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I search in Doc und found that teh command ^Q is a XON (port is open) and ^S is  XOFF (port is close). but how can I see if I recieved XON oder XOFF and how can I use it . I want that my VI go to the end when I recieve XON (= ^Q).
 
thanks


Message Edited by cybername on 07-31-2008 08:26 AM
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Message 7 of 9
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That is CTRL-Q and I've asked you several times is this what you are sending and if this is what you want to receive.

CTRL-Q in hex is 11 and you can right click on a string contro/constant and select Hex Display. CTRL-S is hex 13. If you are going to be working with hex, you should find an ASCII table that lists them.

Message 8 of 9
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thank you  it is working
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Message 9 of 9
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