Overview of Tango Controls¶
What is Tango Controls¶
Tango Controls is an object oriented, distributed control system framework which defines communication protocol and API as well as provides a set of tools and libraries to build software for control systems, especially SCADA.
It is build around concept of devices and device classes. This is unique feature of Tango Controls and make it different to other SCADA software which usually treats a controls system as a set of signals and read and set process values.
Devices are created by device servers. Device servers are programs implementing set of device classes. Device classes are responsible for translating hardware communication protocols into Tango Controls communication. This way you may control and monitor all your equipment like motors, valves, oscilloscopes etc.
Tango Controls communication protocol defines how all components of the system communicates with each other. It is based on CORBA [CORBA] and ZeroMQ [ZeroMQ] protocols. The detail of protocols are not visible to programmers, since it hidden by API.
History¶
The concept of using device servers to access devices was first proposed at the ESRF in 1989. It has been successfully used as the heart of the ESRF Control System for the institute accelerator complex. This Control System has been named TACO [1]. Then, it has been decided to also used TACO to control devices in the beam-lines. Today, more than 30 instances of TACO are running at the ESRF. The main technologies used within TACO are the leading technologies of the 80’s. The Sun Remote Procedure Call (RPC) is used to communicate over the network between device server and applications, OS-9 is used on the front-end computers, C is the reference language to write device servers and clients and the device server framework follows the MIT Widget model. In 1999, a renewal of the control system was started. In June 2002, Soleil and ESRF offically decide to collaborate to develop this renewal of the old TACO control system. Soleil is a French synchrotron radiation facility currently under construction in the Paris suburbs. See [Soleil] to get all information about Soleil. In December 2003, Elettra joins the club. Elettra is an Italian synchrotron radiation facility located in Trieste. See [Elettra] to get all information about Elettra. Then, beginning of 2005, ALBA also decided to join. ALBA is a Spanish synchrotron radiation facility located in Barcelona. See [ALBA] to get all information about ALBA. The new version of the Alba/Elettra/ESRF/Soleil control system is named TANGO [2] and is based on the 21 century technologies :