1. Only certain OHAUS balances are supported by Logger Pro 3. See Which OHAUS balances can I use with Vernier technology? for a list of specific models and the required USB cables.
  2. Is your balance plugged in, turned on, and connected to the computer?
  3. Logger Pro sees OHAUS balances as serial devices even when they connected by a USB cable. Try selecting the appropriate COM port in Logger Pro under Experiment–>Connect interface–>Ohaus.
  4. Are the USB menu items for the balance set correctly? Refer to OHAUS Balance Troubleshooting. Note that there is a switch on the bottom of the balance that needs to be set to the unlocked position in order to access the menu. Also, the USB cable must be attached before the USB menu will appear.
  5. macOS Mojave seems to have particular problems with USB connection to OHAUS balances. If you disconnect and then reconnect the balance while connected to Logger Pro, the balance will not work again until the balance is disconnected, turned off, turned on, and reconnected.

If none of the above fix the problem, email support@vernier.com or use the form below.