I have a PCM RPT-800A UPS, connected to a Windows 2012 machine. I would like to use NUT for communicating with the UPS.  But shortly after installing libusb-win32 for this UPS, the device in Device Manager starts to "blink" (disappear and appear again), looking like it's disconnected and connected again randomly, but frequently (once in 30 seconds, approximately). When I uninstall libusb-win32, it's automatically substituted with default "HID UPS Battery", which works perfectly (no "blinking"), but doesn't give any data to NUT.

So, how do I install libusb-win32 so it won't "blink" in the Device Manager?

UPDATE: As this question has been marked as unclear, I will try to make it more clear by this update using steps:

  1. I have an uninterruptable power supply (UPS) made by Powercom (PCM) company; the model of the UPS is RPT-800A. This UPS has a Universal Serial Bus (USB) port, which can be used to connect the UPS to a personal computer (PC) and read various data from the UPS (percentage of load, input voltage, output voltage, etc.).
  2. There's an application called Network UPS Tools (NUT): https://networkupstools.org.  NUT can be used to read data from the UPS.
  3. So I download the NUT binary package for Windows, install and set it up using manual. Everything works fine for a few hours (I can get the data I need from my UPS using NUT).
  4. And then NUT stops working. The error is "Data stale".
  5. To read the data from UPS in Windows operating system (Windows OS), NUT uses the libusb-win32 library (https://sourceforge.net/projects/libusb-win32/). When this library is installed, it substitutes the current USB device driver in Device Manager with its own custom libusb-win32 driver. So, basically, when I just plug the UPS USB cable into my PC, my Windows OS installs the "HID UPS Battery" generic driver to communicate with UPS. And when I install the libusb-win32 library, the installer deletes the "HID UPS Battery" driver and installs the "libusb-win32" driver instead. So in Device Manager it was "HID UPS Battery" and now it is "libusb-win32".
  6. During my investigation of "Data stale" error of NUT, I open Device Manager and I see that "libusb-win32" device is disappearing and appearing again every 30 seconds approximately. It looks just like someone unplugs the UPS USB cable and plugs in again (but there is no indication of any actual disruption in physical connectivity).

So what I have now:

  • if "HID UPS Battery" driver is used for UPS, it doesn't disappear from Device Manager, but I cannot read any data using NUT.

  • if "libusb-win32" driver is used for UPS, at first it works OK, but in a few hours it spontaneously starts to disappear and then appear again in Device Manager as if someone unplugs the UPS USB cable and plugs it in again.

I do really need to use NUT with this UPS (PCM RPT-800A). So the question again is: how do I make this "libusb-win32" driver to be installed correctly so it won't disappear and appear in Device Manager by itself?

  • Guys from NUT suggested to install debug version of libusb-win32 and to log output by DebugView. I've done this, but it's not something I can understand. Is there something that can lead to fixing? pastebin.com/fEWKmtwe – real_sm Sep 12 '18 at 8:05

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