Unit of Measurement (UOM):

The conversion of one unit to another. Example: 1 Kgs = 1000 gms.

In AX the following areas defines the UOM:

  1. Creation of UOM
  2. Assigning in Released Products
  3. Unit conversion into multiple classes

1. Creation of UOM:

Path: Organization->Setup->Units->Units

Below fields copied from here

Fields Description
Unit Identification of the unit of measure.
Description Descriptive name of the unit of measure specified in the system language.
Fixed unit assignment If this check box is selected, you can identify the unit of measure as one of the fixed units of measure that are listed in the Fixed unit field.
Fixed unit The fixed unit association is used to identify a specific unit of measure. By using this association, specific units of measure can be identified by the business logic in Microsoft Dynamics AX and conversions between the units of measure can be completed.
Unit class The classification for the unit of measure.

The unit class represents a logical grouping of units of measure such as area, mass, or quantity.
System of units The metric system of the unit of measure. Units of measure in the same unit class such as liters and gallon can belong to different metric systems. You can choose one of the following:

  • None: Units of measure that do not belong to the metric or the US typical system of units.
    TipTip
    Examples of units of measure that use the None category are Box and Pieces.
  • Metric units: The international system of measurement.
  • United States customary units: The most commonly used system of measurement in the United States.
Decimal precision The number of decimals that the converted unit of measure is rounded to when a calculation is completed for the unit of measure.
Base unit If this check box is selected, the unit of measure is defined as the base unit within the unit’s unit class. The base unit helps streamline the conversion setup for a unit of measure. When a base unit is defined within a unit class, the number of conversion rules between units of measure in the class can be limited.

Say that you have a conversion rule that enables conversion from milliliters to liters and another conversion rule that enables conversion from liters to gallons. If you have specified liters as the base unit in the Liquid volume unit class, you can convert from gallons to milliliters without a conversion rule between these two units.
System unit Unit of measure that is applied when a measurement or quantity is entered in fields in Microsoft Dynamics AX that are not associated with a specific unit of measure.

Say that you have a company where kg is set as the system unit. In this company, any weight measurement in the Mass unit class, such as net weight, that is entered for an inventory item is identified as kg

2. Assigning UOM in Released Products:

In general for new users the job is done when basic unit is assigned with related conversions however in AX we have to define Unit under 4 places, Example: The Unit for item Cement in Purchase Order is Tons where as internal consumption is in Kgs also when selling could be in M3 as finished produced product.

By default there is no drop down list to select unit in Item code however customization can be done to overcome this. The trick is show all available units and in back end pass standard unit with converted values, see detail here

  1. Sell: To set unit required when purchasing
  2. Purchase: Unit used when creating PR, RFQ and Purchase Orders
  3. Inventory: Unit used when Inventory transactions like Movement, Adjust, Item consumption, transfer etc.
  4. BOM: Unit used when items used in BOM or sub-BOM for Production module

Unit Conversion into Multiple Classes

For all new users don’t get confused by seeing 3 sets where unit of conversion is defined some times related unit may not appear, when to use which set. Remember as above i have mentioned that in Units setup classes are define, yes. When you define a unit to be standard and related logical class then the conversion form is more understandable.

  1. Standard Conversion: Show all standard Conversions irrespective of product
  2. Intra-class conversions: Shows product specific conversions if both units belongs to same class example: volume
  3. Inter-class conversions: Show product specific conversions across the different class

Tip:  Test conversion can be done using calculator for units available in both AX 2012 & D365