Lock part default unit of measure on BOM (rule)

Before editing a system rule, ensure that no other users are using the system. After editing a system rule, close the PDXpert client and start it again.

To prevent unit of measure conversion errors in MRP exports and roll-up reports, this rule is a one-time setting. If this rule is saved as False, then it cannot be reset as True.

To avoid problems with your internal systems and supply chain partners' software, keep this rule set as True.

Administrators open this using the Tools ➔ System Rules… menu.


Ensures that a part's default unit of measure is always used on a bill of materials (BOM).


True: Every BOM uses the Default unit of measure that's been specified on the part's Attributes page. The unit cannot be edited on the BOM.

False: The unit of measure specified on a part can be overridden with a compatible unit of measure on a BOM markup. For example, a part with a default unit (for example, length cm) can be added to a BOM markup, and then be re-specified with a compatible unit (say, mm or inch).

While this rule is False: If you change a part's default unit of measure, use the part's Appears On: BOM list to make sure that the quantity and unit of measure is correct on each BOM.

Data type§


Recommended or default value§



It's highly recommended to keep the default value (True). Many production planning systems and contract manufacturers use a part's default unit of measure everywhere, including on the BOM.

Setting this rule to False gives users greater freedom to specify units of measure on assembly BOMs. However, this is generally useful only in small-volume engineered-to-order or one-of-a-kind products, and is risky for volume manufacturing.


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