There are a few reasons that your scale could stop working. First we need to identify a few things so you can help troubleshoot the problem:

1. Type of Sale - Avery, CAS PDII , CAS SW10 , Metler Toledo, AnD
2. Type of Connection - Usually it's Serial to RJ45, but it may be Serial on the scale to another cable which converts to USB.

If you see in the POS where the weight is displayed:
DC or Er.
This is usually a connection issue. If the cable is a serial to Rj45 then:

1. Turn off the scale
2. Exit the POS Software to the Desktop
3. Confirm the Scale cables are securely plugged in, you may need to unplug and plug back in the cable.
4. Log out of windows - Start Log Off
5. Log back into Windows
6. Turn on the scale.
7. Start back up the POS

Alternatively, you may just try to confirm the connection of the scale, and then turn off and on the scale.

If you need to setup the scale from the begining, go here:

https://docs.google.com/document/d/1Moq4tj2f7hcRvTUvpqzkcMG_HaKODt_ujlHnj93h4to/edit?usp=sharing

https://docs.google.com/document/d/1LZao_6_mDYmuTxnyL_EFhekcQ2i8BbGvcWxi2xko9fA/edit?usp=sharing