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Signals

Signals are unique pieces of data that are connected to a source such as a temperature sensor, a modbus register, or even the result of another processed signal (see transformations). Signals can store history, are available for dashboards and reports, and can have rules applied for determining condition states.

Signal elements in Asset Configuration window

Characteristics

  • Have a current value and timestamp
  • Can be enabled to store history
  • Must have a source, otherwise will remain empty
  • Are available for inputs to transformations and condition rules
  • Dashboards use signals to show data about an asset

Sources

The following are the available source inputs for a signal.

  • Connected Device Channels
  • The output of a Transformation

Info

Choose any signals for your asset

An asset can have signals from any connected device. The signals do not need to be connected to the same device. The asset object configuration does not need to mirror the arrangement of channels on the physical IoT devices.

Properties

The signal properties are inherited from device channels when they are created from a device. Signals that are the output of transforms are defined by the transform itself. Signals have the following properties

Signal editor window

Signal Types and Units

All signals have a type and a unit, which are inherited from the signal's source (e.g. a connected device channel) that are used for storing the data properly, allowing proper visualization options, and to be sure the source of truth can be trusted as data is exported. Most data types support multiple unit types, example the data type TEMPERATURE supports units of °C, °F, K, and °R. Some data types are unit-less (e.g. Number) that allow users to specify a custom unit.
The complete list of signal types and units can be found here:
Exosite Industrial IoT Specification Types Document

Signals can not change type or unit once they are created, as these are important for source of truth, all data is stored in these formats and therefore can not be changed once created.

Dashboard panels allow users to display signal values in different units.

Custom Units

Users can specify a custom unit for Number and String signal data types.

Signals of type NUMBER and STRING can use custom units. These can be inherited from the source device channel configuration or can be entered in the signal configuration window. Custom units do not allow for conversions and typically are shown with an asterisk * next to the unit.

Panel showing a number signal with a custom data unit.

Note: New data types and units can be requested through support requests.

Icons

The icon associated to a signal is tied to the data type to provide a quick way to know what the the signal type is on dashboardss. The icons show up in dashboard panels and throughout the application.

Precision

Specifies the number of decimal points the application will round up to for a numeric data type value when displayed in visualization dashboard panels.

Baseline

Specifies a constant value (applies to Numeric data types only) that is considered the baseline.

Uses:

  • Currently used by the line chart dashboard panels to show a baseline horizontal line, must be enabled in the dashboard panel.

Report Rate

The expected report rate of the values for that signal. It's important to remember that report rates can vary depending on network slowness, device issues, and other possible areas that may cause the source of data to be delayed.

Uses:

Timeout

The time period that would be considered a timeout for the source of the data. Often caused by network problems, device firmware issues, or device's powered off / loss of power.

Uses:

  • Currently used by dashboard panels to show timeout indication for that signal including greying out of the panel, not showing a value (option), and showing a timeout indicator in the panel.

Min / Max

Reserved for future use in the application.

Favorites

Each asset supports selecting up to 4 signals as a favorite which will be shown in group asset lists and tile views. If none are selected, the application will randomly select 4 to show.

Available for Dashboards

By default is this enabled. If disabled, will not show the signal as available when setting up dashboard panels. Used to hide specific signals.

Save History

By default is enabled. If disabled, the system will not store any history for the specific signal, only the last value is kept. Used to lower historical data storage usage.

Control Signals

Control signals are mapped to device control channels, which allow for sending requests to a device and receiving feedback that the device took action on the request.

Control signals show up in the Asset Configuration UI with icons showing bi-directional interface.

Control signals show bi-direction arrows in the signal icons.

Info

How many signals does an Asset support?

The recommended maximum number is 50 signals per asset for the best experience in the application. Up to 100 we recommend talking with support about the possible UX limitations. Above this, please work with support to understand the use case and potential alternative use cases and design patterns.


Last update: April 13, 2021