.. _set_accj_rt:

set_accj_rt
------------------------------------------
This function sets the joint acceleration used by real-time joint commands:

- :ref:`servoj_rt <servoj_rt>`: on DRCF v2, when the next command does not arrive before the robot reaches the target position, the robot decelerates to a stop with this acceleration. On DRCF v3, ``servoj_rt`` does not use this value and stops with the joint acceleration limit of the safety settings. On both, it does **not** limit the ``servoj_rt`` trajectory.
- :ref:`speedj_rt <speedj_rt>`: if the acceleration of the motion exceeds this value, the controller reports an **Info message**, at most once per second, without limiting or stopping the motion. Every joint whose velocity changes needs a value above 0; otherwise the controller reports a warning.

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

.. code-block:: cpp

   bool set_accj_rt(float acc[NUM_JOINT]) {
       return _set_accj_rt(_rbtCtrlUDP, acc);
   };

**Parameter**

.. list-table::
   :widths: 25 20 20 35
   :header-rows: 1

   * - **Parameter Name**
     - **Data Type**
     - **Default Value**
     - **Description**
   * - acc
     - float[6]
     - -
     - Joint acceleration [deg/s²].

**Note**

- The controller applies this value only while real-time control is started with :ref:`start_rt_control <start_rt_control>`. A command sent before start_rt_control is ignored.
- On DRCF v2.12.5 or later and v3.7.0 or later, a value above five times the joint acceleration limit of the safety settings is reduced to that value.
- On DRCF v2, if the value is 0, ``servoj_rt`` stops with the joint acceleration limit of the safety settings instead.
- The value stays in effect until it is changed or the controller restarts. Ending the real-time control session does not reset it.

**Return**

.. list-table::
   :widths: 20 80
   :header-rows: 1

   * - **Value**
     - **Description**
   * - 1
     - The command was sent. This does not confirm that the controller received or applied it.
   * - 0
     - The command datagram could not be sent.

.. note::

   This function is asynchronous. It returns without waiting for the controller to accept or reject the command, so a return value of 1 does not confirm that the robot acted on it. Rejected commands and motion warnings and errors are reported through :ref:`set_on_log_alarm <set_on_log_alarm>`. :ref:`set_on_rt_log_alarm <set_on_rt_log_alarm>` reports only RT session messages, so register both callbacks.

**Example**

.. code-block:: cpp

   drfl.connect_rt_control("192.168.137.100", 12347);

   // The controller applies this value only while real-time control is started.
   // Input period 0: no input watchdog, because this example sends a single command.
   std::string version = "v1.0";
   drfl.set_rt_control_input(version, 0.0f, 4);
   drfl.set_rt_control_output(version, 0.001f, 4);
   drfl.start_rt_control();

   // Joint acceleration [deg/s²]
   float acc[6] = {100.f, 100.f, 100.f, 100.f, 100.f, 100.f};

   if (drfl.set_accj_rt(acc))
       printf("set_accj_rt sent.\n");
   else
       printf("set_accj_rt could not be sent.\n");

   drfl.disconnect_rt_control();

This example sets the value to 100 deg/s² for every joint.

**Tips**

- A lower value gives a longer, gentler stop when ``servoj_rt`` commands stop arriving.