COM port configuration with NI-Serial...

[BenjaminAZ]

All,

I have two questions for you, I have searched through the forums but have not found answers that directly address these issues:

1) There are at least three ways to reassign COM port numbers:

    A) NI MAX.

    B) Windows Device Manager

    C) NiPortConfig.exe

    When is it appropriate to use one vs the others? When should you not use one vs the others? As in, ENET-232/4 converters, motherboard COM ports, etc... What is NI's official stance on this? MAX seems very temperamental when it comes to COM ports in Devices and Interfaces...so I'd like to know if a certain method is preferred?

2) We have a Windows XP SP3 system with NI Visa 4.5.1, NI Serial 3.4, and NI MAX 4.6

    Our computer has 7 motherboard COM ports, 4 ENET-232/4 converters, and 1 ENET-485/4. We've built a duplicate system, but it will intermittently have error BFFF0000h (Unknown System Error (Miscellaneous system error)) when issuing a ViOpen call to various COM ports (NI-Serial only ports, not the motherboard ports). When the error occurs, it will go hard over. The only way to correct it is to reboot the system. After some time, the issue will occur again. Yes, ViClose calls are always issued.

   We have been unable to determine a pattern. We don't believe it's the software setup or NI software versions: we have gone as far as applying a Norton ghost image of a working system (so...working XP, Ni-Serial, NI-Visa)...but the error will still occur. All of our other systems use Visa 4.5.1 and Serial 3.4....

   I'm asking for troubleshooting advice on this one...any ideas? I don't suppose this could be an IRQ issue? I'm not certain of the inner workings of how NI-Serial resolves COM ports with the OS.

Any assistance you can give would be greatly appreciated!

[K C]

Hi,

As far as I know you can only change the COM numbers in the Windows Device Manager.

The best way........

I can tell what I do. I use the alias possibility of MAX to name devices and COM ports. You can even name the COM1 port COM10 but I think this is very confusing.

If I have a interface (COM, GPIB, Ethernet, USB or ...) to a Power Supply I name this connection something like 'PSU_24V' I can develop my program connecting devices to my own computer or to another computer with a remote connection and VISA server. Just be naming the device in MAX I can use the device without the problem of the physical connection number.

For your second question: show us how you use the COM ports. Post your VI's. Maybe there is something wrong there.

Kees

[BenjaminAZ]

Hey, K C, thanks for your response 🙂

You can change COM port assignments in MAX by doing the following:

1. Expand Devices and Interfaces
2. Expand "Serial & Parallel"
3. Select the port of interest.
4. Select the "Advanced" tab on the bottom
5. Change the assignment in the "COM Port Number" dropdown.

I do like your idea about the alias....that could solve problem #1...we use aliases for our TCPI/IP resources, but for some reason I never considered it for serial.

Though....I would still like to know which method is preferred by NI.

Regarding item #2, there's really not much to it...just a ViOpen call. I don't know if there's a list of possibilities for this particular error code?

[K C]

Hi Benjamin,

That's strange I never saw that possibility and even stranger I cannot find it !!   

There is no 'Advance tab' in MAX on my computer 

If you are sure that you are using the COM ports the right way maybe you can update your SW. MAX, VISA and the serial driver are not up-to-date.

It is a very little chance that this is the problem but you never know

Kees

[nyc_(is_out_of_here)]

---

K C wrote:

That's strange I never saw that possibility and even stranger I cannot find it !!   

There is no 'Advance tab' in MAX on my computer 

---

I don't see an Advance tab either on my computer, but then I don't have a NI-Serial card.

I had a USB to Serial converter made by Tripplite where it was possible using their software to choose the COM port for the ports that are on their device not the PC, so maybe that is what is happening for the OP with his NI-Serial card.

[BenjaminAZ]

The Advance tab will be available if you have a NI ENET-232/4 or ENET-485/4 converter---these are what we are using in our system.

[K C]

I checked an old computer with a PCI-8431 and yes on that computer MAX shows the Advance tab.

The computer is that old that I didn't remember it anymore.   

Kees