Units and Time¶
Numbers and Units ¶
All data values for signals are stored as defined in the Signal properties using the signal data type and data unit (when applicable). This is the 'source of truth' for visualization, conversions, data pipeline functions, and storage. More information about Signals
Dashboards and other visualizations will default to using the Signal's type and unit. Dashboard panels can be configured to convert signals from one unit to another as long as it is of the same type (e.g. Temperature).
Numeric Data Presentation and Storage Details
- Numeric signal data values are stored as IEEE Double format.
- Visualizations default to the Asset Signal's Type, Unit, and Precision, but can be configured to convert units in certain dashboard panels and will auto-convert using a user's preferred units.
- The user's profile Number format is also an automatic visual conversion
- All signal pipeline processing (transforms, rules/thresholds, etc) always use the source signal property units and type.
- Signal data can be converted using transforms, which creates a new signal using the specified units - resulting in two signals with the same data essentially.
Number Formats¶
User's may specify how numbers, dates, and times based on personal and regional preferences. These can be configured in their User Preferences
Supported Units¶
A full list of supports signal types and units can be found in this detailed document Supported Asset Signal Data Types and Units. Units are supported end to end, from IoT edge device / sensor to the web application and thus why these are built into the system. This ensures unit conversions can be supported and a source of truth is maintained.
Custom Units¶
When using a signal with data type of NUMBER or STRING, the unit property of a signal can take custom units. These will not support any unit conversion throughout the application.
More information about Signal units and custom units can be found here
Supported Unit Systems¶
| System | Description |
|---|---|
| Asset's Defined/Source Units | (Default) The original signal sources as defined in the asset and asset dashboards. |
| Asset's Unit System | An asset may specify a preferred unit system, which may be different then the signal sources. This is defined at the Asset Information / Configuration level. Asset Overview |
| SI (metric) | SI metric system |
| US | US Customary / Imperial system |
Unit system conversions use an assumption for closest unit to unit conversion which may not fit each personal preference. User's may specify exact unit conversions in their User Preferences.
Unit Conversion ¶
Early Access Functionality
User Preferred Units and Unit Conversion as a Visualization menu option functionality is currently in an Early Access BETA state. Please contact Exosite's support for more information about getting early access to this new feature set.
Signals that are reported as a difference between two other sensor readings or values, or a delta are currently assumed to be like any stand alone sensor reading for unit conversions.. This will provide an inaccurate unit conversion.
There are two ways for users to automatically convert units.
Visualization Settings Menu
The Visualization Settings header menu provides the ability to temporarily switch unit systems (and timezone). When choosing a unit system, this will be indicated in the header and is temporary. The preference does not change your user preferences and will be used temporarily as you browse asset dashboards.
User Preferences
Optional Feature
This feature may not be enabled on all ExoSense instances.
A user's preferences for the user's formats (data, time, and number), and preferred units in most cases allow user's to customize how they view the data, without changing the source of truth. The preferred visualization units are applied to these visualizations when possible, taking priority of the units to be viewed. These settings do not change the source definition of Device channels, Asset Signal Types and Units or to rule and transform function logic.
User's may specify their preferred unit system and also very specific unit conversions to be precise when just changing a unit system may not address the exact unit they want to see.
More information about User Preferences
Timestamps & Timezones¶
No matter where a source device or asset is located and what timezone it is in, the actual data for signals uses UTC timestamps for the source of truth.
Dashboards, asset grid view, and essentially anywhere that shows value timestamps will use the user's timezone specified in their profile preferences. This timezone is set initially based on the user's computer system browser but can be set to any timezone, including UTC if they prefer. Note: Data Reports allow for options for timezone and format.
Timestamped Data and Timezones Summary
- Signal data values are stored using a UTC timestamps.
- The user's preferred timezone is used for visualization of timestamps.
- Time and Date formats are also visual conversions.
Visualization Settings Menu
The Visualization Settings header menu provides the ability to temporarily switch the timezone to view dashboards with. When choosing a timzeone, this will be indicated in the header and is temporary. The preference does not change your user preferences timezone nor the asset's actual signal data storage and will be used temporarily as you browse asset dashboards.
