Simple Calculated Field

Simple calculated fields compute a real-time value using a single mathematical expression — no scripting required. For example, given temperature and humidity telemetry, the expression 243.04 * (ln(humidity/100) + 17.625 * temperature / (243.04 + temperature)) / (17.625 - (ln(humidity/100) + 17.625 * temperature / (243.04 + temperature))) computes the dew point and stores it as dewPoint the moment new data arrives.

Use Simple when you need:

• Derived sensor metrics (dew point, heat index, power = voltage × current)
• Normalization and scaling (calibration factors, unit conversions)
• Threshold-based values (clamping, simple scoring, deltas)
• Cross-entity calculations (combine device telemetry with asset attributes)

1. Open the Calculated fields page.
2. Click the + Add calculated field ⇾ Create new calculated field in the top-right corner.
3. In General, enter a title, specify the entity the field applies to, and select the Simple type.
4. Add Arguments, write the Expression, and configure Output.
5. Click Add to save.

Simple fields support Latest telemetry and Attribute argument types. The data source can be the current entity, another Device or Asset, the Customer, the current tenant, or the current owner.

For full argument configuration details, see Calculated Fields — Arguments.

In the Expression field, write a single mathematical formula that references your arguments by name (e.g., temperature, humidity).

Supported operations and functions:

Category	Supported
Arithmetic	+, -, *, /
Functions	abs, sqrt, pow, min, max, ln, log, ceil, floor, round

The expression produces one result value, stored under the configured output key.

Field	Description
Output type	Time series or Attribute
Key	The name under which the computed value is saved
Decimals	Optional decimal rounding
Use latest timestamp	Time series only — stores the result using the most recent argument timestamp

For output strategy options, see Calculated Fields — Output Strategy.

A Smart Device sends temperature (°C) and humidity (%) as telemetry in real time. Goal: compute dewPoint and store it as a time series key on the same device.

1. Open the Calculated fields page.
2. Click the + Add calculated field ⇾ Create new calculated field in the top-right corner.
3. In General:
   • Title: Dew Point
   • Entity: Smart Device (or its device profile)
   • Type: Simple
4. Click Add argument:
   • Entity type: Current entity
   • Argument type: Latest telemetry
   • Time series key: humidity
   • Argument name: humidity
5. Add a second argument for temperature with the same settings.
6. In Expression, enter:

   243.04 * (ln(humidity / 100) + 17.625 * temperature / (243.04 + temperature)) /
   (17.625 - (ln(humidity / 100) + 17.625 * temperature / (243.04 + temperature)))

7. In Output:
   • Output type: Time series
   • Key: dewPoint
8. Click Add.

Result: Each time temperature or humidity is updated, dewPoint is recalculated and stored as a new telemetry entry on the Smart Device.