Link error: Something went wrong with the connection to the controller

Link error: Something went wrong with the connection to the controller

This article explains what you can check when the 'link error' appears.


  1. Check the configured protocol parameters of the communications port you are connected to.
    1. Terminal X04 for the Q1 and Q2 controllers.
    2. Terminal X02 for the FIT and FORM controllers.
      1. Use the controller buttons to navigate to the correspondent parameters.
      2. For ControlsStudio (CS) and the controller to be able to communicate, the communicationsport should be configured as shown below:
        1. Modbus Slave
        2. Baudrate: 57600
        3. Parity: No parity
        4. Data bits: 8
        5. End bits: 1
        6. Address: 1
  1. Check the polarity of the communication cable running from the USB-Nano to the controller.
    1. USB-Nano A (Rx) is to be connected to L1+ on the controller.
    2. USB-Nano B (Tx) is to be connected to L2- on the controller.
  1. Double check if the controller connector is firmly and correctly inserted.
  1. Check the integrity of the used communication cable. This can possible by measured.
    1. This can be checked by performing a resistance measurement on the wires. Please note that the cable must not be connected to any device when performing the measurement.
  1. Verify if the USB-Nano device is correctly recognised by your PC.
    1. Open the control panel.
    2. Open the device manager.
      1. The two items as displayed below should be visible.

        1. In normal circumstances, the USB nano is automatically recognised and correctly installed by your computer. However, if something has gone wrong, the drivers of the USB nano may need to be updated. Take a look at the following article.
          1. Be sure to reboot your PC after attempting first installation.
  1. Check if the COM-port has correctly been selected in the CS program.
    1. If the selection is blank, nothing is selected, and no communication is possible.

    2. The earlier identified COM-port should be selected to establish a communication.

  1. When attempting to connect to the controller by pressing the connect icon in CS, be sure to insert the correct Admin password.

  2. A connection between the controller and CS software can only be established if the controller is programmed with CS compatible software.
    1. If you had not CS compatible software inside, but would now like to establish a connection, it is first required to re-program the controller with CS compatible software.
      1. Open the kitfile
      2. Open the controller programmer tool
      3. Move all files to the right column
      4. Power down your controller
      5. Start the CS programming by clicking the programming icon
      6. power up the controller
  3. Sometimes it feels like CS is instantly triggering the link error. It is not taking it's time to attempt to establish a connection. To resolve this:
    1. Close the CS application software.
    2. Unplug the USB-Nano device
    3. Plug the USB-Nano device back in the PC.
    4. Restart CS.

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