I am trying to find out how to get a list of the SSIDs of available WIFI networks from LabVIEW. We are doing automated manufacturing testing on a product which has a WIFI chip and is set up to act as a WIFI access point. When the device is powered, it broadcasts its SSID, and a nearby computer can connect to the access point and then communicate with device to read data and set parameters using http. We want the manufacturing test to confirm that the WIFI hardware is working by confirming that the SSID is being broadcast. Up until now, this has been done manually by observing the available networks in Windows. How do I get a list of the available networks in LabVIEW? I found something close to what is needed here https://forums.ni.com/t5/Example-Code/WiFi-Network-Scanning-and-Connecting-with-LabVIEW/ta-p/3731977. and here https://forums.ni.com/t5/Example-Code/WiFi-Library-for-LabVIEW/ta-p/3736625. Show Networks.vi uses the command "netsh wlan show networks" in a command line to get a list of the networks, but this does not seem to work reliably. Sometimes it shows most or all of the available networks, sometimes it only shows the network that is currently connected, and sometimes it shows old results (does not detect a newly available network for a minute after the network becomes available). Any thoughts on how to reliably do what I want in LabVIEW. I'm wondering whether there is a way to do it using WMI and dotnet nodes.

Try if this works. LabVIEW 2018

LabVIEW

Find SSIDs of available WIFI networks

Solved!

Error 170 indicates “device in use”. Without that retry loop I got regularly an error on my test computer. I was deliberating if it was better to simply ignore that error or rather do a retry. My tests indicated that it lasted 500 to 700 ms for that condition to clear so I decided to do a retry.

I suspect that WLanScan() does actually very little in reality. The Windows WLan service will scan the networks regularly anyhow. When that error occurs it is most likely just doing that. Normally, WLanScan is propably just a little tickle for the service to remind it that there is still a client present. In the unlikely case that the service hasn’t performed a scan already for some time it will trigger one but otherwise just return a no error code to say “yes I did it”.

Rolf Kalbermatter
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