Epicor Kinetic · Inventory
Epicor Kinetic UOM classes: how conversions work and why transactions lock the inventory UOM
Applies to: Epicor Kinetic and Epicor ERP 10.2. Navigation paths and screen layouts can differ slightly between releases, so always validate changes in Pilot first.
Short answer
A Unit of Measure (UOM) Class groups related units (count, weight, length, and so on) around one base unit. A part's on-hand quantity is stored in its Inventory UOM (Part.IUM). Once a part has inventory transactions, Kinetic stops you changing that UOM. To change it, you normally create a new part number.
UOM class basics
Each part belongs to a UOM class set up in UOM Class Maintenance. Each class has a base UOM, and the other units in the class are defined by their relationship to it. Example: in a Count class with EA as base, DZ converts at 12, so receiving 2 DZ adds 24 EA.
The three UOM fields on a part
- Inventory UOM (Part.IUM): how stock, BOM requirements, counts and costs are held.
- Sales UOM (Part.SalesUM): the default on quotes and sales orders.
- Purchasing UOM (Part.PUM): the default on purchase orders.
Sales and purchasing units must be convertible to the inventory unit.
Conversions within a class vs between classes
- Within a class (for example FT to IN): defined once in UOM Class Maintenance (table UOMConv) and shared by every part in that class. Each row has a conversion factor (ConvFactor) and an operator (ConvOperator: multiply '*' or divide '/'). Always read the operator together with the factor: "multiply by 12" and "divide by 0.0833" are not the same entry.
- Between classes for one part (for example EA to LB for a steel bar): defined on the part itself, in Part Maintenance on the UOM conversion tab (table PartUOM).
Example: a bar weighs 4.75 LB. With IUM = EA, you define the EA-to-LB relationship on the part. A PO for 475 LB then converts to 100 EA on receipt. Always test with a receipt in Pilot.
Why the inventory UOM locks
Every inventory transaction (PartTran) stores its quantity in the part's inventory UOM. Changing the unit afterwards would reinterpret history: 100 LB would become 100 EA, and costs and balances would no longer reconcile. Kinetic blocks the change once transactions exist. The exact message text varies by version, so we do not quote it here.
How to change the UOM in practice
Check with your finance lead first. A common approach:
- Count and adjust stock to zero (Quantity Adjustment), recording the value.
- Close or reassign open jobs, sales orders and purchase orders for the old part.
- Mark the old part inactive (and rename or re-describe it as obsolete).
- Create the new part with the right UOM class and inventory UOM.
- Bring stock into the new part at the appropriate cost.
Update BOMs, price lists and approved supplier lists to point at the new part.
FAQ
Can DMT bypass the lock?
No. DMT calls the same business objects as the screens, so the same validation applies.
What is dual UOM?
Dual UOM (tracking, for example, pieces and catch weight simultaneously) is an optional licensed capability (such as Advanced UOM in manufacturing environments). Confirm module licensing and release support with your Epicor account team.
What if a conversion is entered wrongly?
Quantities will be over- or under-stated on every transaction that uses it. Test conversions in Pilot before using them in Production.