How are ASRL numbers selected?

[dj143]

I installed two PCI-485/8 cards for a total of 18 serial ports including the two original COM ports that are part of the comptuer.  Please look at the attached sceen shot of MAX.  COM11 is associated with ASRL15 and COM15 is associated with ASRL25.  How do I fix it so COM11 is ASRL11 and COM15 is ASRL15?  I also attached the visaconf.ini file for reference.  I'm using MAX v.4.2.1.3001 and NI-Serial v.3.2.0

Dave

[Chris_R.]

Hi Dave,

Click here for a KnowledgeBase on how to change the VISA Aliases for your COM ports.  Make sure the names are not already reserved by something else before changing them. 

I hope this helps!

[dj143]

Hi Chris,

Thank you for your response.  However, I need to change the ASRL number and not the alias.  In the previously attached screen shot, the system skips ASRL11 for COM11 and sets it instead to ASRL15.

Why does it skip ASRL11?  There is a similar problem with the ASRL number associated with COM15.

I can change the alias name.  But this will not work with our current applicaitons because the programming assumes that the ASRL numbers are sequential without skips or gaps.  Our applications are sent out to end-users who have no clue what an ASRL number is.  Therefore we have to only use COM numbers and keep it simple.

If I cannot change the ASRL number, is there a way to programmatically retrieve the ASRL numbers that are associated with the COM numbers?  This way the system will be automated and no one will have to work with the ASRL numbers.  I could have the application open the visaconf.ini file and retrieve the ASRL / COM associations.  However, the visaconf.ini file does not get defined properly.  I always have to manipulate it.

Dave

[Chris_R.]

Hi Dave,

In the device manager, access the properties of the COM port and see if you can change the COM numbers.  I was able to change the COM numbers for my COM ports and the ASRL number automatically changed for me.  Go to the Control Panel>>System>>Hardware Tab>>Device Manager>>Ports.  Double click on a port then go to the Port Setting tab and select Advanced Settings.  See the screen shots below.  If ASRL11 is already used/reserved by something else (now or in the past), then that is probably the reason you cannot select it.  Try this out and see what happens.  Here are some screen shots to help you if needed.

Have a great day!

Message Edited by Chris_R. on 08-21-2007 10:51 AM

[dj143]

Hi Chris,

Sorry for not responding sooner.  I've been out of town.

 

I tried to temporarily change the alias names to no avail.  Please see the attached for more details of what I attempted to correct this problem.

Thanks,

Dave

[menchar]

I have this same issue - I'd like to do an explicit assignment of an ASRL number rather than use the default enumeration that VISA comes up with.  The reason for this is that we run a set of several test stations that we'd like to keep configured in a consistent way, so that our test apps find the same resources.  Unfortunately, we have a virtual serial port in a framegrabber that is enumerating differently on different test systems.

Is there any way to ster / reassign the ASRL enumeration for VISA resources?

It looks like NI didn't have an answer for this thread ...

[Marand]

Hi,

You can edit the visaconf.ini as is shown at the following link:

http://digital.ni.com/public.nsf/allkb/B089F9352D262EE686256F1100001EE0?OpenDocument

Regards, 

[menchar]

I understand that I can change or delete the alias for any given ASRL, but that wasn't the question.

Can I change the mapping of the ASRL to physical device (i.e. not the ASRL to alias mapping)?

In the example at the link you provided, can I make ASRL10 map to a physical serial port, and make ASRL1 map to a parallel port?

I don't want to simply remove an alias (as this link describes), I want to remap an ASRL to a different physical device.

[fromm8]

Hi memchar

The changes that you are able to make are the available options in MAX or modifying that file (visaconf.ini).

Regards

[PhilippPahlke]

menchar, I have the same issue in the same situation.

Did you finde a solution for this or anyone else?