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Why are my serial ports being reassigned on OS X?
ScrapIron
Member
02-24-2004 08:43 AM
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I have been doing a lot of development on LabVIEW 7 for OS X. For the most part I am happy. But the reassigning of my serial ports on the keyspan USB/rs232-4 is extemely agravating. My four instruments are now located on ports 8, 9, 10 and 11. The port numbers seem to be growing periodically. It completely disables my software when this happens and I have no good way to deal with it. I found and ran Visa config but this didn't do a wit of good. It has no help documentation at all. It seemed like making a port "static" would keep it from floating around but it doesn't. I have seen another question to this affect in this forum but it was never answered.
BeckyB
NI Employee (retired)
02-27-2004 09:50 AM
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Hello ScrapIron �
When exactly do the port numbers change? Is it when you unplug the USB adapter and plug it back in? If so, it could be that your OS has not released the previous port numbers and therefore assigns higher numbers.
This could also be an issue with the driver of the third party (keyspan) device. Please make sure you have the most updated version of the keyspan driver (version 2.1).
A simple workaround to this problem may be to use the VISA Find Resources VI to programmatically find the instruments.
For information on how a USB-to-Serial Adapter with LabVIEW assigns port numbers on a Macintosh, see this KnowledgeBase.
Have a great d
ay!
Becky B.
Applications Engineer
National Instruments
When exactly do the port numbers change? Is it when you unplug the USB adapter and plug it back in? If so, it could be that your OS has not released the previous port numbers and therefore assigns higher numbers.
This could also be an issue with the driver of the third party (keyspan) device. Please make sure you have the most updated version of the keyspan driver (version 2.1).
A simple workaround to this problem may be to use the VISA Find Resources VI to programmatically find the instruments.
For information on how a USB-to-Serial Adapter with LabVIEW assigns port numbers on a Macintosh, see this KnowledgeBase.
Have a great d
ay!
Becky B.
Applications Engineer
National Instruments
Becky Linton
National Instruments
Field Engineer
Office: 734-464-2463
Cell: 248-709-2822
Email: becky.linton@ni.com
National Instruments
Field Engineer
Office: 734-464-2463
Cell: 248-709-2822
Email: becky.linton@ni.com
03-30-2004 01:22 PM
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I did some more testing with a clean system. I installed the Keyspan driver then ran VisaConfig. Visa found ports ASRL1 to ASRL4 just as I would expect. I exited VisaConfig then restarted it. It asks right when it starts if you want to search for dynamic devices. I said yes and it found 4 new ports at ASRL5 to ASRL8. I don't think I restarted the computer in between and I definitely never removed the keyspan adaptor. In LabVIEW, when I ask for visa ports I get ASRL5-ASRL8 only but VisaConfig shows ASRL1 to ASRL8.
