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USB-RS-232 Adapter. We are trying to use NI-VISA with such an adapter. Have you had any success?
Andy Toth
Member
10-14-2004 10:40 AM
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I am trying to use NI-VISA through a USB-RS-232 adapter. What I atrying to do is have NI-VISA see the adapter as a COM1 and allow communication over the USB bus. Does this work? Has anyone had any success?
Chris_Rake
NI Employee (retired)
10-14-2004 10:58 AM
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We have fully tested the NI USB-232 adapter with NI-VISA on Win2k and XP, and have not seen any problems.
On the other hand, I've seen some 3rd party adapters that have poor behavior - what brand adapter are you using?
On the other hand, I've seen some 3rd party adapters that have poor behavior - what brand adapter are you using?
Ben
Knight of NI
10-15-2004 07:47 AM
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Hi Chirs,
I just oredered one of your USB-232 adapters exactly for this reason.
I hope can count on you to help if I have trouble.
Ben
I just oredered one of your USB-232 adapters exactly for this reason.
I hope can count on you to help if I have trouble.
Ben
Retired Senior Automation Systems Architect with Data Science Automation LabVIEW Champion Knight of NI and Prepper LinkedIn Profile YouTube Channel
Chris_Rake
NI Employee (retired)
10-15-2004 09:08 AM
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Of course!
10-15-2004 02:04 PM
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Chris,
I beleive that is an IOGEAR. The request is coming from our end-customer. What we did is to use the NI-VISA IO Layer in some application software. The software was designed for RS-232 using NI-VISA. What I am seeing is customers getting these adapters for their laptops which only have USB support. What I will try to do is get one of these adapters and test the combination using the NI-VISA with them. Any insight we be helpful. I have been lead to beleive that the adapter and driver emulates a COM1 port. I am hoping that NI-VISA just leverages the USB-RS-232 adapter as a generic serial port.
Andy
I beleive that is an IOGEAR. The request is coming from our end-customer. What we did is to use the NI-VISA IO Layer in some application software. The software was designed for RS-232 using NI-VISA. What I am seeing is customers getting these adapters for their laptops which only have USB support. What I will try to do is get one of these adapters and test the combination using the NI-VISA with them. Any insight we be helpful. I have been lead to beleive that the adapter and driver emulates a COM1 port. I am hoping that NI-VISA just leverages the USB-RS-232 adapter as a generic serial port.
Andy
Chris_Rake
NI Employee (retired)
10-15-2004 03:04 PM
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My understanding is that VISA makes WIN32 calls, and if the serial device behaves properly, those calls will work regardless of the type (USB, built-in, etc.). VISA doesn't know anything about the type of interface being used (ethernet, RS-232, PCI, etc.) - managing those differences is the responsibility of the serial device's driver.
10-15-2004 03:32 PM
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Chris,
Can NI-VISA handle COM numbers greater than 4. For an example most PCs may have a COM1 and COM2. SOme have COM3 and COM4. If the USB-RS-232 adapter emulates to COM5, will the NI-VISA layer handle it? What is the limit? We only have had success with NI-VISA up to COM4. My thinking that some of theese adapter drivers may default to COM5 in order not to conflict with COM1-COM4. Any thoughts?
Can NI-VISA handle COM numbers greater than 4. For an example most PCs may have a COM1 and COM2. SOme have COM3 and COM4. If the USB-RS-232 adapter emulates to COM5, will the NI-VISA layer handle it? What is the limit? We only have had success with NI-VISA up to COM4. My thinking that some of theese adapter drivers may default to COM5 in order not to conflict with COM1-COM4. Any thoughts?
Chris_Rake
NI Employee (retired)
10-15-2004 04:05 PM
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I'm not sure why you wouldn't be able to use COM numbers higher than 4, I have not had this problem with my testing.
10-18-2004 10:25 AM
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Chris,
We figured it out while you were checking into the issue as well; the customer was using a a Toshiba P25 laptop with a Keithley 6485 Picoameter (serial interface), and one of the problems was that the USB-RS-232 driver was assigned to COM14(!). The customer forced the USB to Serial to be on COM3. The Toshiba is now talking to the 6485 with no problem using NI-VISA. The issue appears to be related to higher level COM#s.
Thank you for your support.
Andy Toth
Keithley Instruments
We figured it out while you were checking into the issue as well; the customer was using a a Toshiba P25 laptop with a Keithley 6485 Picoameter (serial interface), and one of the problems was that the USB-RS-232 driver was assigned to COM14(!). The customer forced the USB to Serial to be on COM3. The Toshiba is now talking to the 6485 with no problem using NI-VISA. The issue appears to be related to higher level COM#s.
Thank you for your support.
Andy Toth
Keithley Instruments
