> ## Documentation Index
> Fetch the complete documentation index at: https://notevil.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# CAPLfunctionFDXEnableFreeRunningMode

# FDXEnableFreeRunningMode

[Valid for: CANoe DE](../../../Shared/FeatureAvailability.md) • CANoe:lite DE • CANoe4SW DE • CANoe4SW:lite DE

## Function Syntax

```plaintext theme={null}
long FDXEnableFreeRunningMode(long fdxClientHandle, word groupID, word flags, dword cycleTime, dowrd firstDuration);
```

## Description

This function activates the **Free Running** mode for the specified FDX client. The behavior of the function corresponds to the reception of a **FreeRunningRequest** command via the [FDX protocol](../../../CANoeCANalyzer/Interfaces/FDXProtocol.md).

You can find further information about the **Free Running** mode in the manual [CANoe\_FDX\_Protocol\_EN.pdf](javascript:startDemoLoader\('CANoe_FDX_Protocol_EN.pdf'\)).

## Parameters

* **fdxClientHandle**: FDX client for which the **Free Running** mode should be activated.
* **groupID**: Identifies the data group inside the FDX description file.
* **flags**: The flags describe when the data group will be transmitted.
  * 1: Transmits data group at pre start phase of the CANoe measurement
  * 2: Transmits data group at stop of measurement
  * 4: Transmits the data group cyclically while the measurement is running. The transmit cycle is defined by the fields **cycleTime** and **firstDuration**.
  * 8: Transmits the data group if the function [FDXTriggerDataGroup](CAPLfunctionFDXTriggerDataGroup.md) is called.
* **cycleTime**: Time period in nanoseconds for the free running mode.
* **firstDuration**: Time interval in nanoseconds for the first transmit cycle.

## Return Values

* **0**: Successful function call
* **-1**: The parameter **fdxClientHandle** is invalid.

## Example

[Coupling of two CANoe Instances using the FDX Protocol](../../../CANoeCANalyzer/Interfaces/FDXProtocolCouplingCANoeInstances.md)