Will not connect to device or will disable shortly after connecting

19 Dec 2023


The user gets a "Failed to communicate with the following modules:..." message on initial boot or "An error occurred on the CAN port.  Ensure CAN cable is still connected" message if Mirus disconnects after establishing a connection. Resetting the system power may or may not help.


  1. Ensure the System Controller is turned on and you have power to all the modules.
  2. Check to see if there is a solid green power light, flashing yellow status light, and no flashing red light on each of the modules.
  3. Ensure all the cables are properly connected.
    • A USB or serial cable (if H2) between the tablet dock and the System Controller. 
    • A CAN cable between the System Controller and the GrainGage.
  4. Unplug the USB or serial cable from the dock (if used) and plug it directly into the tablet to check if the dock is dysfunctional.
  5. Ensure the correct GrainGage plugin is enabled.
  6. Shutdown and reboot the tablet. Turn off the System Controller and leave it off for 30 seconds. Turn it back on again and attempt to connect.
  7. Unplug the CAN and power cables on the modules, leave them for 30 seconds. Plug the power and CAN cables back in and attempt to connect.

NOTE: if the problem only occurs when operating the machine, the issue may be related to vibration.  USB ports wear out and may cause intermittent communication issues with the USB to CAN cable.  Try a different USB to CAN cable or plug it into a different port on the tablet.   

If you are still having issues, please contact one of our HarvestMaster Field Service Engineers