Connection trouble with a USB Postage Scale

OS X 10.13.3 on iMac

If I plug in a USB postage scale, should it show in Finder under devices? It doesn't and I can't find it anywhere else.

I use an extension (Rock Solid Scale Reader) with Chrome so Chrome can read the scale. I print postage from a webpage interface (xpsshipper.com) but frequently I have to unplug the scale and relaunch the extension so the extension can read the scale and the webpage can take that weight and calculate postage.

Once I get it working it works fine, but a day or two later I have to unplug, etc. all over again. And many times I have to do that a few times to get it to "take".

New USB scale plugged into the back of the iMac.

Thanks for your help!

Al