Instrument Control (GPIB, Serial, VISA, IVI)

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Setting XonLim and XoffLim using VISA API

Hi. Due to NI dropping support for Serial devices on 64-bit Windows, I'm forced to update some of my code packages from Win32 COM calls to those found in the VISA API. I'm trying to match up my INSTR attributes using a DCB from one of the packages for reference, and can't figure out how to set the XonLim and XoffLim values. I've scanned through the VISA programmer's manual a few times and can't find anything. 

Also I've read this : http://forums.ni.com/t5/LabVIEW/Can-I-set-XonLimit-and-XoffLimit-for-serial-port-communication/m-p/1...

 

From that article, it seems those properties can be set under LabVIEW. Is it not possible to set them otherwise ? Thanks for any suggestions !

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Does this help? 

Programmatically Changing Serial Properties Using LabWindows/CVI and NI-VISA: 

http://www.ni.com/example/26510/en/

 

Angela Li 

Applications Engineer

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Angela,

 

Thank you for the reply. The example you linked was about as far as I got initially. It was the XonLim and XoffLim in particular I was trying to change, though it appears those attributes cannot be directly changed through VISA API.

 

In any case, I read more up on the DCB settings using the reference DCB I was trying to match and noticed that FOutX and FInX were set to false. From my understanding, with those two properties set to False, software flow control is turned off so the XonLim and XoffLim are don't cares. Most other states from the reference DCB were able to be duplicated for the VISA serial instrument (stop bits, parity, byte/word length, baud and hardware flow control [rts and dtr])

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Yes, that is correct. It seems like DCB has more attributes to set for serial communication. The main serial communication properties for VISA API are the ones that you have listed.

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