Selling by Weight: What Should Your POS Take From the Scale?

A connected scale should do more than place a changing number on the till. Agree which product is being weighed, whether the container is excluded, when the reading becomes an order quantity and what happens before the next item. Those decisions determine what staff are actually asking the customer to pay for.

This is a workflow brief for live weighing at a POS, not a guide to weighing prelabelled packages or converting boxes into pieces. Commercial weighing can involve equipment and legal requirements. Have the proposed device, installation and use assessed by a competent supplier or adviser. A working integration or green software indicator is not independent compliance certification.

Begin with the product and price basis

In a fictional refill shop, a customer brings a container for loose goods. The product, quantity unit and price basis need to be clear before staff accept a reading. Selecting another product must not leave an old price attached to the new weight.

The Odoo 19 scale guide describes configuring a product for weighing and setting its sales price for the relevant unit of mass. Its connection also requires an IoT system. These are specific integration requirements, not proof that any USB scale will work with any browser till. Confirm the supported model, connection and installed software before purchasing hardware.

Your brief should distinguish a live scale reading from a manually entered quantity or weight encoded on a supplier label. If more than one path is allowed, staff should know which one produced the order line.

Exclude the container deliberately

Odoo documents a Tare action that resets the scale to zero and subtracts the container's weight. In your actual workflow, demonstrate the empty-container step and what happens when a different container is used. Do not assume staff can reuse a previous container deduction without an agreed procedure.

Ask how the operator can tell that tare has been applied and whether a cancelled attempt affects the next weighing. These are proposed acceptance questions, not additional features established by the cited page. Avoid commissioning an unexplained negative adjustment after the sale as a substitute for a clear weighing process.

Separate seeing a reading from accepting it

In Odoo's documented sequence, staff select the product, place it on the scale and see a computed price. They then click Order to add it to the cart. Seeing a measured value is therefore not the same action as adding the weighed product to the sale.

Agree what the customer and operator see before confirmation: product, mass unit, accepted quantity and resulting line amount. Ask what happens if the load changes while the operator is confirming, and which reading is actually saved. Do not promise automatic stability detection or a particular capture rule without demonstration on the supported device.

After confirmation, inspect the saved line rather than only the live display. A later change on the scale should not silently rewrite a quantity already accepted under your agreed workflow.

Make the next weighing a fresh operation

The Odoo guide explicitly requires the scale to return to zero before another product is weighed. Otherwise its Order button remains unavailable until reset. Include that sequence in the demonstration, rather than testing only one successful item.

Also agree an outage procedure. If the scale disconnects, should selling weighed products stop, or is there an authorised alternative? Any manual path needs its own visible origin and review rule. Do not carry forward the previous reading merely to keep the queue moving.

Accept a complete counter-service journey

Use invented product records and an appropriate supervised device demonstration. Test a container deduction, a second container, cancellation, a product change, two successive weighed items and a disconnection. Compare the visible reading with the saved quantity and unit, price basis and line amount. Have the equipment specialist handle calibration and regulatory checks separately.

Include these outcomes in your acceptance criteria before the POS integration discussion. The useful result is a sale staff can explain from product selection through accepted weight, not merely a scale that sends numbers.