![]() ![]() ![]() (Refresh is not needed if the application is started after the device's driver is installed. In other words, when "Refresh" is clicked in the COM port VISA list box, any new devices installed should be and normally are seen. Either way, sometimes, not always, depending on the COM port number, after reusing that port number by installing a new device which picks up that old, freed-up number, LV VISA doesn't see it. I've also tried uninstalling them the normal way when the device was actually connected. In DM View menu you can "Show hidden devices" and uninstall them as if they were connected. We were able to uninstall orphaned (non-present) COM ports from DeviceManager ("DM") by starting it from a command console (DOS window) with a special command-line switch, "set devmgr_show_nonpresent_devices=1" then "start devmgmt.msc" (I have this in a batch file). On one of our production PC's we were close to COM900 ports (HyperTerminal sees only up to COM256) when suddenly Win7 would not allow any more. This is so our customers can use multiple devices on a PC. Fine. We have a custom driver for our device and since each device's USB bridge chip is programmed with a different serial number, every time we connect a new device to the PC the installer runs and assigns a new COM port number. ![]() The USB port is actually a virtual COM port (VCP) - a USB to Serial converter or "bridge". We use it to set up products we design and manufacture through our device's USB serial port. Here's some more info: I wrote a LabView (LV) program and deployed it (via the Application Builder) to some of our production department's PCs (some Windows XP and some Windows 7). It should not be possible that HyperTerminal sees a COM port but VISA does not. ![]()
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March 2023
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