Guide
How to set up scale label barcodes in a grocery POS
If your deli, butcher or produce counter has a label-printing scale, its labels can go straight through the till with no typing. This guide explains what's inside those barcodes, how to find your scale's layout, and how to test it before a busy day.
The 13 digits, explained
Scale labels use the same EAN-13 barcode as packaged goods, but with numbers your shop makes up. Codes starting with 2 are reserved for "in-store" use, which is why scales use them. A typical label:
| Part | Example | Means |
|---|---|---|
| Prefix | 21 | "This is a scale label." Usually 20 to 29. |
| PLU | 01234 | The item's code on the scale. 4 to 6 digits. |
| Value | 00437 | Price in cents (4.37) or weight in grams (437 g). |
| Check digit | 1 | Worked out from the other 12. Catches misreads. |
The prefix, the PLU length and whether the value is a price or a weight are set on the scale. Your till needs the same three settings.
Step by step
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Print a test label
Weigh something on the scale and print a label for an item whose PLU you know, say 1234. Write down the 13 digits under the barcode.
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Find the prefix
Look at the first two digits. If it's between 20 and 29, you're on the common layout. Some scales use one prefix for price labels and another for weight labels.
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Find the PLU length
Find your PLU in the digits after the prefix. If you see 01234, that's 5 digits with a leading zero. If you see 1234 followed straight away by the value, it's 4.
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Price or weight?
Compare the next digits with what's printed on the label. If they match the price (00437 and 4.37), it's a price label. If they match the weight (00874 and 0.874 kg), it's a weight label.
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Give each item the same PLU in the POS
Every item sold from the scale needs the same PLU on the scale and on the till. In OmniSync Retail, the PLU is a field on the item. For weight labels, also set the price per kilo on the item.
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Enter the layout
In OmniSync Retail, open Settings and find scale labels. Set the prefixes, the PLU length and price or weight. The defaults (prefixes 20 to 29, 5 digits, price) suit most scales.
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Test at the till
Scan the test label. The right item should appear at the right price. Then cover part of the barcode and scan again: a good till refuses it rather than guessing. Test one label from every scale you own.
When it doesn't work
The label scans as an unknown item
The prefix probably isn't in your list, or the PLU on the item doesn't match the scale. Check the first two digits and the item's PLU.
The price is ten times too big or small
The PLU length is off by one, so a digit of the PLU is being read as part of the price. Try 4 or 6 instead of 5.
The label is refused
The check digit doesn't match, which means the barcode was misread: a crease, a smudge, or a printer running low. Rescan, or type the PLU. If one scale's labels are always refused, clean its print head.
Try it with OmniSync Retail
OmniSync Retail reads scale labels on the Professional plan and above, and checks every one. More about scale labels.