.. index::
   single: unisim

=======================
The unisim application
=======================

unisim emulates a set of
`UniDrive <https://acim.nidec.com/drives/control-techniques/products/ac-drives/unidrive-m>`_
motor control devices all run the :doc:`uniserv <uniserv>` program.

unisim is an
`EPICS <http://www.aps.anl.gov/epics/about.php>`_
application that implements an
`IOC <https://docs.epics-controls.org/en/latest/guides/EPICS_Intro.html?highlight=IOC#ioc-software-components>`_ and uses the
`SocketCAN <https://www.kernel.org/doc/html/latest/networking/can.html>`_ interface for
accessing the `CAN bus <http://en.wikipedia.org/wiki/CAN_bus>`_.

By defining a
`Virtual CAN Bus interfaces <https://docs.kernel.org/networking/can.html#the-virtual-can-driver-vcan>`_
on your system, it is possible to run unisim and and :doc:`idcp <idcp>`
your system without any specialized hardware.

This can be used to test IDCP, unisim acts as a digital twin of the undulator.

Download the application
------------------------

You download the sources with
`mercurial <https://www.mercurial-scm.org/>`_
with this command::

  hg clone http://hg.code.sf.net/p/idcs-unisim/code unisim

Configure and build
-------------------

You configure the project with the script ``configure.sh``.

The script has an online help that can be shown with::

  ./configure.sh -h

.. note::
   If you work from the internal network of the
   `Helmholtz-Zentrum Berlin <https://www.helmholtz-berlin.de>`_,
   always run configure.sh with option ``--local custom-HZB.sh``.
   Use this option also when you display the online help since the
   help text is changed by this option.

The configure script ensures that `sumo <https://epics-sumo.sourceforge.io/>`_,
`bii_scripts <https://bii-scripts.sourceforge.io/>`_ and
`pyexpander <https://pyexpander.sourceforge.io/>`_ are installed.
If one of these applications is missing it is downloaded and installed in a
`Python Virtual Environment <https://docs.python.org/3/library/venv.html>`_.

`sumo <https://epics-sumo.sourceforge.io/>`_ is then called to
download and compile
`EPICS Base <http://www.aps.anl.gov/epics/about.php>`_  and other
EPICS device supports needed by the application.

Finally, 'configure.sh' can also compile the application itself.

For a simple local build of everything run::

  ./configure -v -y

For a display of other configure.sh options run::

  ./configure -h

Set up of your environment variables
------------------------------------

If at some point you want to recompile the application, you have to configure
your environment first. Run::

  source ./setenv.sh

.. note::
   If configure.sh didn't have to install any programs, setenv.sh is empty.

Configure the virtual CAN Bus
-----------------------------

.. note::
   This only works when the application was built before since scripts
   from the SOCAN device support are used for initialization.

.. note::
   You need 'sudo' rights on your system for the following command.

In order to set up the virtual CAN bus interfaces run::

  ./setup-vcan.sh

Start the application
---------------------

.. note::
   When your Linux host has more than one IP address select one of these
   addresses where the IOC should run and append ``--ip IP-ADDRESS`` to the
   command below.

.. note::
   You may omit option '--sudo' when you don't have 'sudo' rights on your
   system. However, in this case the program cannot run with Linux real time
   priorities.

Run::

  ./start-ioc.sh --sudo

Now you are ready to go to run
:doc:`idcp <idcp>`.