Selling items by weight

If you sell fruit, meat, cheese or anything else by weight, your shop scale prints a barcode label that carries the product code and either the weight or the price. RKCoders POS reads those labels.

To be clear about what is and is not supported: the till reads labels printed by a scale. It does not read a live weight from a scale connected by cable or network. The scale prints, the cashier scans.

How a scale barcode works

A scale label is an ordinary barcode with a structure agreed in advance. A typical one looks like this:

2 12345 01234 5
│ │     │     └── check digit
│ │     └──────── weight or price, in the smallest unit
│ └────────────── the product code (PLU)
└──────────────── prefix that marks this as a scale label

The parts that vary between shops are the prefix, how many digits the product code takes, and whether the embedded value is a weight or a price. That is exactly what you configure.

Configuring it

Open Settings and find the weighing-scale barcode section. You need to tell the till:

• The prefix that identifies a scale label. 2 is the most common choice, but check what your scale actually prints.
• How many digits carry the product code.
• Whether the embedded value is a weight or a price. Get this wrong and every weighed item will be priced absurdly, so it is the first thing to check if something looks off.

Set these to match your scale’s own configuration. If you do not know it, print one label and read the digits off it against the diagram above.

Matching the label to a product

The product code inside the barcode is matched against the SKU on your products. So the product’s SKU in RKCoders POS has to be the same code your scale is programmed with.

The cleanest way to do this is to decide the codes once and program both sides from the same list. If your scale is already in service, take its PLU list as the source of truth and set the SKUs in the catalogue to match.

Testing before you open

Weigh something, print a label, scan it at the checkout, and check three things: the right product came up, the quantity is the weight you actually put on the scale, and the line total is what you would expect.

Do this for one product from each price band. It takes two minutes and catches a wrong prefix immediately.

When a label will not scan

Work through it in order:

• Does the product’s SKU in the catalogue match the PLU the scale printed?
• Is the prefix in Settings the one on the label?
• Is the digit count right? A code that is one digit out will either find nothing or find the wrong product.
• Is the product ticked as Weighed?

If the barcode scans as a plain number into the search box but does not resolve to a product, the scanner is fine and it is the barcode rules that need attention.