Windows Laptops Not Connecting to CAS LP1000 / LP-Works — Check the COM Port

Windows Laptops Not Connecting to CAS LP1000 / LP-Works — Check the COM Port

Products Discussed: CAS LP1000N(P) Scale, LP-Works,

Question

I have three Windows laptops. One connected to a CAS LP1000 easily. The other two will not connect at all. Firewall is turned off on all of them. Is there a different setting I missed?

Answer

Yes. Go to Windows Device Manager and look under Ports (COM & LPT) to see which COM port the scale is using. Then set that same COM port in LP-Works.

Firewall being off is useful, but it does not assign the serial port. If two PCs use different COM numbers (for example COM3 on one laptop and COM5 on another), LP-Works will fail on the machines that do not match the port configured in the software.

🔌 How to Find the Scale COM Port in Windows

  1. Connect the CAS LP1000 to the laptop with the same cable you use on the working machine.
  2. Right-click Start and open Device Manager.
  3. Expand Ports (COM & LPT).
  4. Look for the scale / USB-serial adapter entry (often labeled USB Serial Port, Prolific, FTDI, or similar).
  5. Note the COM number in parentheses — for example COM3 or COM5.
  6. Open LP-Works and set the scale connection to that exact COM port.
  7. Save, then test weight capture again.

Tip: Unplug the scale and watch Device Manager. The COM entry that disappears is the scale. Plug it back in to confirm the number.