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instrument number does not match com port

I have a serial port adapter installed on my system as COM35.  MAX has assigned it ASRL71, not ASRL35.  I have put 2 of these adapters on my system, both recognized by Windows XP.  Max is showing ASRL::71 on COM35 and ASRL::25 on COM25.  Max has a resource for ASRL::35 that is not recognized on the system.  If I change COM35 to COM4 in windows, MAX will not find the resouce without rebooting the computer.  Take a look at the attached document it has screen shots of the system.

 

This is the first time that I have had MAX do this.  Is there anyway to force MAX to correctly assign instrument numbers to the COM port?

 

Thanks

 

 

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Well-

 

I'm guessing that you've had a lot of devices attached from time to time.  MAX will reserve resources to "Help" you essentially that means that each time you plug in a specific USB-SER convertor it remembers that you wanted that on called "MyAliasXYZ". If you want another device to use that resource "MyAilasXYZ" you need to clear the VISA device associations so the alias is available again.

untitled.PNG

 

From MAX Select Tools> NI VISA> VISA options and you will get this Screen- From the General Settings Aliases branch you can rename or even clear individual (or all) Aliases and then COM35 will be available for use by another device

 


"Should be" isn't "Is" -Jay
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That is what I was showing in the screen shot of the list of resources and aliases window.  I have cleared that out twice.  When I plug in the device for COM35 it creates a phantom ASRL35 and locks it, then also creates the ASRL71 that I can use.

 

 

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RBrown,

 

That seems like an odd thing. Have you tried going through these articles?

 http://digital.ni.com/public.nsf/allkb/AE830D99E30CB61486256C7900697999?OpenDocument

http://digital.ni.com/public.nsf/allkb/FF9EEE0B28569617862573210073B69F?OpenDocument

http://digital.ni.com/public.nsf/allkb/767056E924AE087186256E4B005BFFDB?OpenDocument

 

I think these may help 🙂 Are you able to change the name in LabVIEW?

Sam S
Applications Engineer
National Instruments
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