In This Guide
A tolerance value is incomplete without its units and meaning. On a load cell liquid filling machine, the team must know whether a selected screen field defines a deviation, a boundary or another controller setting. Entering a familiar number from a specification into an unfamiliar field can produce a recipe that appears plausible but represents the wrong acceptance rule.
Confirm the documented target basis, units and interpretation of every tolerance field before entry. Distinguish absolute deviation, percentage and explicit limits where the installed controls use them. Have engineering review the translated requirement, then witness the ordered decision function with approved test samples.
Start from the written quantity requirement
Identify the approved target and acceptance rule, including whether the requirement refers to net mass, gross mass or another defined basis. Keep packaging tare and product quantity separate. Do not let the HMI field name determine the specification after the fact.
The H M load cell page describes empty-container tare and filling to the selected net-weight target. The supplied controller and any acceptance or reject logic still need their own documented scope. Confirm which functions exist rather than assuming that every weight display includes a pass/fail decision.
Confirm units and display scaling
Record the unit shown for the target and each tolerance entry. Ask whether the display uses a fixed unit, selectable unit or a documented scaling convention. Preserve decimal precision as displayed instead of rounding values informally.
Check that the approved requirement and the entry refer to the same quantity. Do not substitute a volume value for a mass entry or assume a percentage field accepts an absolute mass deviation. Any conversion needed for the application must have an approved basis and reviewer.
Ask how the field translates into a decision
Determine whether the selected controls expect an allowed deviation around a target, separate lower and upper limits, a percentage or another defined form. These are possibilities to confirm, not claims about the installed HMI. Ask how equality at a boundary is treated.
Review whether the field affects filling cut-off, an inspection decision, an alarm or a separate rejection function. One parameter can sound like acceptance tolerance while controlling a different part of the sequence. Keep those meanings explicit in the recipe record.
Use a tolerance-entry review sheet
| Review item | Evidence to preserve |
|---|---|
| Written requirement | Approved target, quantity basis and acceptance rule |
| Screen field | Exact label and documented function |
| Units | Displayed unit, scaling and precision |
| Entry interpretation | Deviation, percentage, boundaries or other defined meaning |
| Decision boundary | Documented handling of values at the limit |
| Approval | Reviewer, recipe revision and witnessed result |
Use an approved worked example from the actual requirement to check the translation. Do not create a generic tolerance value and treat it as suitable for every liquid or pack.
Witness the actual ordered function
Agree a supervised test using approved samples or the supplier’s documented simulation method. Compare the displayed result and decision with the reviewed requirement. Keep guards active and follow normal product-handling controls.
If automatic rejection is included, verify its route separately from the acceptance decision. If it is not included, state how an unacceptable sample is held or removed through the approved process. A correct limit calculation does not establish that every affected pack is controlled.
Preserve the units when recipes are copied
Record the final entry with units and the reviewed meaning in the released setup. When copying or restoring a recipe, verify these fields rather than checking only the recipe name. A new controller revision or interface should trigger the relevant compatibility review.
Keep screenshots as supporting evidence with the documented field definitions. If the interpretation remains unclear, leave the recipe unapproved and ask the supplier for clarification. This prevents a unit or boundary misunderstanding from becoming an accepted production instruction.
Customer Questions
Can the same number represent different tolerances?
Yes. Its units and interpretation matter. An absolute deviation, percentage and explicit boundary are different entries.
Does a tolerance field always control rejection?
No. Confirm whether it controls filling, an alarm, inspection or an ordered rejection function.
What should be checked when copying a recipe?
Verify quantity basis, units, field meaning and the actual values against the approved requirement, not only the recipe name.
Product References and Further Details
These pages describe published equipment arrangements. Review the supplied machine, actual materials and agreed operating requirements when applying the guide.
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