ftdi usb comunication lost after ftdi VCP device is connected

[StefanS]

Dear alls,

I'm working with two devices. One is a USB device and one is serial device both driven by ftdi chip.

As FTDI offers CDM drivers that will support the comunication for both devices at almost! the same time...there should be no problem with that and it works as long as they are not pluged in at the same time. 

The problem that occurs is that right after I pluged in the serial device, which is a USB to RS 232 converter the USB device will no longer be available in LabView, without showing any changes in the device manager. The serial device seems to be dominant. It works in both cases. The actual LabView driver for comunication with the USB device is a .NET file. Maybe there is a problem with that file or NI-VISA.

thanks for your help

Stefan

[Andrea_Perin]

Dear Stefan,

I guess it could be a compatibility issue between the FTDI  drivers and the VISA standard. As  reported in the following link, each Virtual COM Port implements different functionality, that could not be officially supported by MAX or VISA.

Using Virtual COM Ports or Third-party USB-to-Serial Adapters with VISA in MAX

I suggest you to verify with FTDI the VISA compatibility of the driver. It could be there the reason of such an unexpected behavior. 

Best regards.

Andrea