I have Magna Power XR power supplies (2 kW each) that I control through LabVIEW (version 2012). Everything was working just fine but after making few normal changes in the main code, it suddenly stopped working. One thing I noticed is that MAX somehow loses communication with the serial ports after trying to communicate with the power supply. Meaning that the communication with the port was working fine at first, but after trying talking to the power supply it stops. Like there's something with the power supply's VIs that causes the port to stop working (I'm just trouble shooting). The error I get is "VISA: (HEX 0xBFFF0072) The resource is valid, but VISA cannot currently access it". Any hint is appreciated, especially if you have this kind of power supplies. Thanks a lot!