Installation of a USB Driver

In order to use the USB interface to connect to the power supply the PC needs the Kniel USB driver. The driver is based on an driver from FTDI .
We have two ZIP archives, one for Windows up to Windows 7 and one for Windows 8 and later. Each archive contains a driver for 32bit and 64bit architechtures.

Configuration of a USB driver

Direct connection USB USB

After installation connect your power supply directly to your PC using a standard USB (A-B) cable, do not use USB hubs inbetween.
To check, open the Device Manager from the Control Panel of the PC. You should see two new devices: a Kniel Power Supply listed under Universal Serial Bus controllers (USB) and a new Serial Port under Ports (COM & LPT). You should be able to connect to the power supply.

Using a RS232 USB converter

If you use a USB-serial converter (USB at the PC and RS232 at the power supply), the driver needs a slightly altered configuration.


Timing is an important issue while communicating over a serial connection. Most serial interfaces have buffer registers that temporarily store information and thus compensate for fluctuations during communication. The speed of the connection has a direct relation with the amount of data that goes over the connection and how fast a buffer register with a given size is emptied.

The default setting of the USB driver after installation is 16ms (this may vary depending on hardware and driver). This settings needs to be altered to 1ms. Otherwise the buffer would store several replies form the power supply and send them all at once when the buffer is full. Communication with the power supply can only work properly when the answer is forwarded immediately.

You will need administrator permissions to change the settings and depending on your operating system a reboot might be necessary.


Open the Device Manager in the Control Panel.
Device Manager

Choose the proper interface. In this example we use USB Serial Port (COM5).
Choose the interface
The General tab will open. Click on Change settings, you may have to authenticate as admin.

Switch to the tab Port Settings.
Port settings

Choose Advanced….

Change the setting of the Latency Timer to 1ms.
Change the setting of the Latency Timer
Click OK and close the previous dialogs. You might have to reboot your computer to activate the new setting.

In addition, please refer to the corresponding chapter of the description of your power supply (deutsch: Beschreibung).

Known Issues

Some users of FTDI silicon have reported that an FTDI device will not install if connected to a USB 3.0 port. This is partly related to some descriptors not being returned correctly or stored in unexpected registry locations. Please check the related FTDI Technical Note TN_152  for more details.

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Fixed voltages
for 19” systems

Ajustable power supplies
for 19” systems

Programmable power supplies
for 19” systems

energy for 19” systems

Fixed voltages
for wall mounting and DIN-rail mounting

Adjustable power supplies
for wall mounting and DIN-rail mounting

Programmable power supplies
for wall mounting and DIN-rail mounting

energy installation for wall mounting

Firmware, Flash-Tool, Drivers

General information


Kniel System-Electronic GmbH
Kurzheckweg 8 · 76187 Karlsruhe · Germany ·