Multiple visa resources settings

[edmonton]

Hi application engineers,

I have 4 USB data acquisition devices and want to connect via a 4 port USB hub to my computer. 

I had successfully made all 4 devices working together and smooth after many time tries. My labview program  can recognize the 4 devices and run smooth thereafter with no problem. however, it is really difficulty  to get all 4 online again once one or two of the devices are disconnected from the USB hub and reconnected to the USB hub. 

I checked port setting on windows control panel,  and also check the ports using NI MAX, both show proper port settings. See included the first image below.

My program can populate the 4 ports/ visa resource names (see the left side) after clicked refresh and  were selected properly (see the middle), however, after clicked run program, the visa resource became disconnected as shown on the right side of the second image. I went back to check port settings using windows control panel and NI Max, they were still the same as shown in the first image. 

I also tried to reboot computer and start program again, the issue remained. 

I do not have such an issue if just connecting one device. 

Could someone help me with the issue?

Thanks,

Gu