Scale Not Working

Troubleshooting guide

This guide helps you resolve issues when Derby cannot connect to or read from your weight scale.

USB/HID Scales

Scale Not Detected

Check the physical connection

Ensure the USB cable is firmly connected to both the scale and your computer. Try a different USB port.

Verify scale power

Make sure the scale is powered on and displaying a reading on its own screen.

Restart Derby

Close and reopen Derby after connecting the scale. USB devices are detected at startup.

Check Device Manager (Windows)

Open Device Manager and look under "Human Interface Devices" for your scale. If it shows a yellow warning icon, the driver may need reinstalling.

Wrong or Unstable Readings

  • Calibrate the scale — Follow your scale manufacturer's calibration procedure
  • Check units — Ensure the scale is set to grams, not ounces or pounds
  • Wait for stable reading — Don't press F5 until the scale display stabilizes
  • Zero the scale — Press the tare/zero button before weighing

Serial Scales (Torrey, Rhino)

Cannot Find COM Port

  1. Open Device Manager (Windows) or System Information (Mac)
  2. Look under "Ports (COM & LPT)" for your serial adapter
  3. Note the COM port number (e.g., COM3, COM4)
  4. In Derby, go to Settings > Scale and select that COM port
USB-to-Serial Adapters

If using a USB-to-serial adapter, you may need to install drivers from the adapter manufacturer. Common chipsets include CH340, PL2303, and FTDI.

Connection Errors

Verify these serial settings match your scale:

  • Baud rate: 9600 (most common for Torrey/Rhino)
  • Data bits: 8
  • Stop bits: 1
  • Parity: None

Torrey Scales: Continuous Mode

Torrey LEQ/PCR scales can be set to continuous transmission mode. Derby automatically detects stable readings when the weight stops changing.

To enable continuous mode on Torrey scales:

  1. Power off the scale
  2. Hold the MODE button while powering on
  3. Navigate to serial settings
  4. Set transmission to "Continuous"

Platform-Specific Issues

Windows

  • Run Derby as Administrator if USB devices aren't detected
  • Check Windows Security settings for USB device blocking
  • Update USB drivers via Windows Update

macOS

  • Grant Derby permission to access USB devices in System Preferences > Security & Privacy
  • For serial adapters, install the appropriate driver (CH340, PL2303, FTDI)
  • Check System Information > USB to verify device detection

Linux

  • Add your user to the dialout group: sudo usermod -a -G dialout $USER
  • Log out and back in for group changes to take effect
  • Check /dev/ttyUSB* or /dev/ttyACM* for serial devices

Still Not Working?

If your scale still isn't working:

  1. Check if your scale model is supported — see supported scales
  2. Try the scale with another application to verify it works
  3. Contact support with your scale make/model — we may be able to add support