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Overview

What Are Functions in ATLAS?#

Functions in ATLAS are user-defined calculations that transform raw telemetry data into meaningful, derived parameters. They are written in a scripting language called Function Definition Language (FDL) and can be used just like any other parameter in displays, dashboards, and analysis workflows.

Functions are ideal for: - Creating custom metrics (e.g. converting speed from m/s to km/h). - Filtering or smoothing noisy data. - Performing conditional logic or statistical analysis. - Integrating external logic via DLLs or MATLAB.

🔍 Why Use Functions?#

Use Case Example
Data Transformation Convert raw sensor data into engineering units.
Derived Metrics Calculate lap averages, deltas, or performance indicators.
Real-Time Analysis Apply logic to live telemetry streams.
Custom Logic Implement domain-specific calculations without external tools.

✍️ Anatomy of a Function#

  • Parameters: Referenced using $, e.g. $RPM.
  • Constants: Global values defined outside the function.
  • Processors: Built-in compiled functions for math, filtering, etc.
  • Statements: Control flow like if, for, while.
  • Return: Every function must return a value.

🧠 Function Properties Explained#

General Properties#

Property Purpose
Name Unique identifier for the function.
Description Optional metadata for documentation.
Format Display format (e.g. %5.2f).
Units Engineering units (e.g. kph, °C).
Display Min/Max Axis scaling for visualisation.

Function Properties#

Property Description When to Use
Function Mode Determines how the function is evaluated over time. Use Instantaneous for real-time; Coverage Cursor for historical review.
Calculation Mode Controls how often the function is evaluated. Use Fixed frequency for filters and time-based logic.
Calculation Frequency Sets the rate of evaluation in Hz. Match this to your data rate or filter requirements.
Interpolate Between Samples Fills in values between samples. Enable for smoother curves or aligning parameters with different rates.
Join Gaps Around Null Prevents gaps in live data. Useful for real-time dashboards where continuity is important.

🔧 Using the Function Parameter Browser#

This panel lets you search and insert:

  • Parameters from loaded sessions.
  • Constants (global or session-specific).
  • Other Functions.
  • Processors.

Adding Parameters#

  • Type $ then press Ctrl + Space to auto-complete.
  • Or double-click from the Parameter Browser.

🧮 Built-in Processors#

Processors are pre-compiled functions that run faster than interpreted FDL code.

Categories#

Type Examples
Math abs(), sqrt(), log(), exp()
Trigonometry sin(), cos(), atan2()
Filtering Filter(), MedianFilter9()
Interpolation LinearInterpolate(), BiLinearInterpolate()
Special LapMax(), SessionMean(), SetMarker()