This Weighing Technology Companion Specification describes how a scale system is addressed via OPC UA. For this purpose, the following primary use cases for the different scale types from section 5.1.2 were considered. Other use cases can also be covered or specified in other standards (vendor or Companion Specification).

In all defined use cases the scale system usually has the role of an OPC UA server. Therefore, this specification describes and defines the way an OPC UA client can read or write data and control the scale system via OPC UA. A scale system may also have a different interface (e.g. an HMI) that can control the scale as well. Some peripheral devices (e.g. printer, feeder) are also described in this specification but the communication between the peripheral devices and the scale is not part of the description.

NOTE: The OPC UA Companion Specification for Weighing Technology does not take into account any use cases that are affected by legal requirements (like official verification). For example, further parameters may be necessary for external data access or existing parameters may not be read out. A country-specific extension of the Companion Specification would be conceivable.