Configuring a Data Group
A data group is a collection of data group elements logically grouped together for a specific purpose. Its primary function is to organize data received from and sent to field devices. A data group might contain only a few elements or hundreds of elements. These elements can be changed when a field device configuration changes. How and why elements are grouped together depends on field device requirements, system requirements, and other variables, like user design.
There are two basic ways to access a data group:
The two interact, but the device template file provides a higher degree of configurability. The device template file enables you to make broad changes that can potentially affect many remote device configurations. The remote device editor, however, can be used to make higher-level changes and to make configuration changes specific to a smaller subset of remote devices using the same device template file.
For some EIEs, data groups can be defined at the field-device level rather than in a device template file or device editor. These EIEs are documented as having device-level data group support. Methods of configuring these data groups vary by EIE, but the data group definitions have the same .xml structure as those defined in a device template file.
If a remote device requires multiple instances of a data group, the data group can be ordinalized. This means that you define the group once in the device template file but add multiple instances of it in the Device Definition Service (DDS). Templates can contain a mix of ordinalized and non-ordinalized data group types. If you map UDCs to data group elements in an ordinalized data group, the facility of the data group element is the device facility. This is true for all instances of the data group. You can change the facility in the DDS.
More:
Data Group Ordinals and Facility Ordinals
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