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Troubleshooting - Connection Issues

Can't connect to the laser

  • Make sure you have any necessary drivers installed for your laser. If your machine came with its own software, you might have to install that in order to get the driver for your device.
  • A common driver for Chinese diode lasers is this one:
  • On Windows systems, a driver for Ruida and TopWisdom controllers is available at the end of the LightBurn installer - just check the box for the FTDI driver. (See Installation: Windows)
  • If you use a Trocen controller, you might have to install LaserCAD to get their driver.
  • Make sure you are physically connected to the laser, and have chosen the correct type of laser or controller in LightBurn, and the right connection method.
  • Some systems don't automatically connect - you might have to choose the correct port the first time. (See Connecting to the Laser for details)

Losing connection

The most common reasons for connection loss with USB are:

  • Poor quality USB cables, lacking shielding or noise suppression. If your laser came with a cable, try a different one.
  • USB cable length - USB cables are limited to 16 feet. If your cable is longer than this, it may need an amplifier or active extension for the signal to remain strong enough to be read correctly at the other end.
  • Another device on the same circuit as your laser, like a mini-fridge, air compressor, water chiller, etc. Any of these things powering up may cause a small power drop that can make the laser 'brown out' and temporarily disconnect or reset.
  • Poor bonding / grounding - Bonding is tying the various metal parts of a device together, so that if one part builds up a charge, all the other parts build up the same charge. If your laser is not bonded, static can build up on the laser head or rails. If the laser is not grounded (earthed), that static build-up can eventually discharge through the USB connection to the PC, causing comms errors. This is especially common with lasers driven by belts that interact with plastic wheels. Tying the frame parts of the laser to each other, and a ground connection can eliminate this.

USB port sleeping

If it thinks a connection is idle, Windows can put the port into a power-save mode, which can make your device stop talking to it. This is especially common with laptops.

If you are having issues where you often lose the USB connection after a period of time, try the following:

Windows 7: 54

Windows 10: 202

Connecting to the wrong port

If you have multiple devices connected to your computer, it is possible that LightBurn will see the other devices and attempt to communicate with them. If this becomes a problem, you can force LightBurn to ignore the extra ports with a PortExclude.txt file.

  • Go to File >> Open Prefs Folder to open LightBurn's prefs directory
  • Create a file called PortExclude.txt
  • In that file, list the ports you want to exclude, exactly as they show up in the port selection drop down in LightBurn. Each port should be on its own line
  • Save the file, and LightBurn will ignore the ports you've told it to filter out

screenshot showing device ports

Copy the name exactly as shown in the dropdown