.. index::
   single: Introduction

============
Introduction
============

The Insertion Device Control System, IDCS, is a system to 
control 
`Undulators <https://en.wikipedia.org/wiki/Undulator>`_, a special
type of Insertion Devices, 
at the `BESSY <https://en.wikipedia.org/wiki/BESSY>`_ synchrotron facility.

The Control Hardware
--------------------

The system consists of an

`IOC <https://docs.epics-controls.org/en/latest/guides/EPICS_Intro.html?highlight=IOC#ioc-software-components>`_
that is either:

- A `VME <http://en.wikipedia.org/wiki/VMEbus>`_ bus based host running
  `RTEMS <https://www.rtems.org>`_.
- A `PC <https://en.wikipedia.org/wiki/Personal_computer>`_ 
  with `Linux <https://en.wikipedia.org/wiki/Linux>`_.

and one or more motor control devices that communicate with
the IOC via `CAN bus <http://en.wikipedia.org/wiki/CAN_bus>`_.

.. attention:: There are two motor control devices in currently in use. The
   "MOCON" device is deprecated, all new undulators use the "UniDrive" device.

The Control Software
--------------------

For the 
`IOC <https://docs.epics-controls.org/en/latest/guides/EPICS_Intro.html?highlight=IOC#ioc-software-components>`_,
the system uses
`EPICS <http://www.aps.anl.gov/epics/about.php>`_
as software framework. This is the Insertion Devices Control Program, IDCP.

The motor control devices also have a program that uses their propriatory 
programming system. This is 'moserv' for the MOCON device and 'uniserv' for
the unidrive type.