This article explains the function of templates as predefined tag sets, their different types, and how users can apply them to data points.
Templates are special predefined tag sets and an essential part of bringing a site online and running analytics. Templates are applied by the Platform and users to clearly identify two key pieces of information from each point - 'Type' and 'Function'.
Templates are predefined tag sets built into the Platform.
Rationale for Templates
When points are brought in during a device import, their metadata (name, type, description, etc.) appears as it was defined on the BMS by the BMS contractor when the building was commissioned. Point metadata is typically in shorthand, so users should apply templates in order to have consistent, readable key point information metadata for the platform to reference.
In order to have consistent, readable points for users to reference, we renamed the points in the data cleansing phase of the point selection process.
In this context, the most important information contained in the point metadata is the information type of the point (i.e. is it a temperature, status, command or percentage); and the function of the point (i.e. what specifically is it measuring?).
These two pieces of information are captured in the Platform using 'Templates.' Templates tell the Platform how to correctly process point data and apply logic, and the Platform uses these to reference each point.
Templates are categorized into two groups to capture this information – one to capture the point information type, and one to capture the function of the point. These are called the ‘Base Template’ and the ‘Object Template’, respectively. Base templates describe the point information type, while object templates describe the point function.
‘Base Templates’ define the information type of the point and are automatically assigned by the Platform based on known point properties where possible, such as unit of measure or analog/binary type. Some examples of base templates are:
The same base template can be applied to multiple points on a piece of equipment if appropriate; the base template displays what type of data to expect from a point.
Object templates add focus to the base template by specifically identifying the point function. For example, a point with the ‘Temperature’ base template may have a ‘SpaceTemperature’ or ‘ReturnAirTemperature’ object template. The object template tells us specifically what information from the equipment the point is returning.
Each point of a device should have a unique object template. Having duplicate object templates on one device can cause sharing issues when logic is deployed to that device. This issue can be managed by assigning appropriate tags.
Duplicate Object Templates
Most equipment will not have multiple sensors to perform the same function. For example, a VAV box with two 'SupplyAirTemperature' sensors will not have duplicate object templates. However, some compartmentalized equipment such as a large Air Handling Unit (AHU) or Cooling Tower (CT) may have multiple components that perform the same function.
A CT may have multiple fans, each with its own 'FanSpeed' point and associated object template. In this case, tagging would be utilized to create a tag group and tags to separate the two cooling tower cells, and associated object templates, into individual device 'compartments'.
To make running analytics as straightforward as possible, users should avoid assigning duplicate templates to a single piece of equipment, like two SpaceTemperature templates on a VAV box. However, if it makes sense to have multiple instances of the same object template on a device, then it should be assigned that way and managed through additional tag groups and tags.
Templates are applied during the point import process in Site Builder.
The Platform automatically assigns base templates based on point metadata; there will be occasions where user-assigned base templates are required however. Users should verify the automatically assigned base templates to ensure that your points are read correctly.
Object templates are manually assigned by users. Users choose these templates from a predefined list built into the Platform that best match the point function based on the available metadata or supplementary information.
Base Templates are generated based on the communication protocol (BACnet, MODBUS, API, etc.) point data type. Sometimes the point type is been defined incorrectly at the data source - all assigned base templates are user-editable for situations like this.
Example: Applying Templates to a VAV
As part of our site setup in Site Builder, we have brought in a series of VAVs. Each VAV is considered a 'device' item and has a number of points associated with it. These are shown in Table 1.
The Platform processes the points and automatically assigns a base template to each point (Table 2). The user then goes through and assigns an appropriate object template for each base template to each point (Table 3). This process needs to be completed for all VAVs (and other equipment) in the project.
Figure 22. Templating Workflow for a Single VAV.