.. _change_operation_speed:

change_operation_speed
------------------------------------------
This function adjusts the operation velocity.  
The argument is the relative velocity as a percentage of the currently set velocity and has a value from 1 to 100.  
Therefore, a value of 50 means that the velocity is reduced to 50% of the currently set velocity.

Available in Auto mode only. In other modes the function returns false and prints "this command can only be used in auto mode. please change to auto mode as robot mode". The mode check uses the value returned by :ref:`get_robot_mode <get_robot_mode>`.

**Definition** |br|
``DRFLEx.h`` within class `CDRFLEx`, public section

.. code-block:: cpp

    bool change_operation_speed(float fSpeed) { 
        return _change_operation_speed(_rbtCtrl, fSpeed); 
    };

**Parameter**

.. list-table::
   :widths: 20 20 20 40
   :header-rows: 1

   * - **Parameter Name**
     - **Data Type**
     - **Default Value**
     - **Description**
   * - fSpeed
     - float
     - -
     - Operation speed (1–100%) |br|
       Represents the relative velocity ratio compared to the currently set value.

**Return**

.. list-table::
   :widths: 10 20 70
   :header-rows: 1

   * - **Value**
     - **Type**
     - **Description**
   * - 0
     - int
     - Failed
   * - 1
     - int
     - Success

**Example**

.. code-block:: cpp

   string strDrlProgram = "loop = 0\n"
                          "while loop < 3:\n"
                          "    movej(posj(10,10,10,10,10,10), vel=60, acc=60)\n"
                          "    loop = loop + 1\n";

   if (drfl.get_robot_state() == STATE_STANDBY) {
       if (drfl.set_robot_mode(ROBOT_MODE_AUTONOMOUS) && drfl.get_robot_mode() == ROBOT_MODE_AUTONOMOUS) {
           // The operation speed can be changed only in Auto mode
           if (!drfl.change_operation_speed(40)) {
               printf("change_operation_speed failed\n");
           } else {
               ROBOT_SYSTEM eTargetSystem = ROBOT_SYSTEM_VIRTUAL;
               drfl.drl_start(eTargetSystem, strDrlProgram);
           }
       }
   }

This example changes the robot's **operation speed** to 40% of the current setting  
and then executes a simple **DRL motion loop** in Auto mode.  
The new speed value applies immediately to all subsequent motion commands executed by the controller.