How much control do you need to dance TANGO?

This set of slides introduce the TANGO control system for the SKA telescopes, using analogies between tango dancing and the paradigms of the TANGO control system.

The talk was given in the context of the Engineering Q&A talks of the SKA Organisation.

Transcript

1. How much control do you need to dance TANGO? Juande Santander-Vela SDP/TM Element Systems Engineer
2. TANGO: SCADA for SKA SCADA: Supervisory Control And Data Acquisition TANGO: TAco Next Generation Object-oriented (control system) ➥ TACO: Telescope and Accelerator Control Objects Not that foreign to astronomy!
3. TACO @ Hartebeesthoek Radio Astronomy Observatory
6. Why TANGO for SKA? Need for a common control middleware across the SKA Need for industrial-strength SCADA Open Source, very large, vibrant community Some experience in astronomy: TANGO is TACO++ Preferred to ALMA Common Software & EPICS Very successful in synchrotron world
7. How do you TANGO? The TANGO Control System Manual Version 9.2
8. The TANGO Control System Manual Version 9.2 RTFM! Looks easy!
9. Tango & Control There’s a leader There’s a follower
10. Tango & Control Inputs (follower) • Torso orientation • Distance between chests • Centre of gravity • Pressure on the back • Distance to other dancers • …
 Outputs (follower) • Leg movement • Arm movement • Hip position • Centre of gravity Needs constant attention Refined with experience
11. TANGO & Control There’s a leader → Device Client There’s a follower → Device Server additional information to send on the wire, TANGO version control etc. These details can and should be wrapped in TANGO Application Programmer Interface (API). The API is implemented as a library in C++ and as a package in Java. The API is what makes TANGO clients easy to write. The API’s consists the following basic classes : • DeviceProxy which is a proxy to the real device • DeviceData to encapsulate data send/receive from/to device via commands • DeviceAttribute to encapsulate data send/receive from/to device via attributes • Group which is a proxy to a group of devices In addition to these main classes, many other classes allows a full interface to TANGO features. The following figure is a drawing of a typical client/server application using TANGO. Client Database TANGO TANGO Server TANGO Cmd Attrib CORBA attrib CORBA opera API API Devices CORBA CORBA CORBA
12. OK for one couple
13. What about ballrooms? Control Strategy: Startup, Dance, Stop Distributed, autonomous control
14. What about systems? Leaders are many times followers of other leaders (military hierarchy) Anyone could be a follower of anyone (swarms) Strategy allows for clear decision and action at the different levels Think hierarchically
16. These are modes! (of the dancers)
17. Or are they attributes?
18. A TANGO Device Server Device server Instance Name State Attribute_1 Attribute_2 Attribute_3 Attribute_4 Command_1 Command_2 Command_3 ` ΅ ῰ Class-dependent Think hierarchically
19. A TANGO Device Server Device server Instance Name State Attribute_1 Attribute_2 Attribute_3 Attribute_4 Command_1 Command_2 Command_3 Think inheritance ` ΅ ῰ Class-dependent
20. A TANGO Hierarchy Device1 Device2 Device3 Device4
21. A TANGO Hierarchy Device Server1 Device Server2 Device1 Device2 Device3 Device4
22. A TANGO Hierarchy TEL- MGT Device Server1 Device Server2 Device1 Device2 Device3 Device4
23. A TANGO Hierarchy TEL- MGT Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB
24. A TANGO Hierarchy TEL- MGT Client1 Client2 Client3 Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB
25. A TANGO Hierarchy Client1 Client2 Client3 Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB
26. A TANGO Hierarchy Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB Generic Client This is the power of TANGO
27. A TANGO Hierarchy Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB Generic Client
28. A TANGO Hierarchy Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB Generic Client
29. A TANGO Hierarchy Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB Generic Client Generic Client Each one for each specialist
30. A TANGO Hierarchy TEL- MGT Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB
31. A TANGO Hierarchy Proxy1 Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB Proxy2 Device Server4 Device Server3 Device5 Device6 Device7 Device8 TEL- MGT
32. A TANGO Hierarchy Proxy1 Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB Proxy2 Device Server4 Device Server3 Device5 Device6 Device7 Device8 TEL- MGT DB
33. A TANGO Hierarchy Proxy1 Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB Proxy2 Device Server4 Device Server3 Device5 Device6 Device7 Device8 TEL- MGT DB DB
34. A TANGO Hierarchy Proxy1 Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB Proxy2 Device Server4 Device Server3 Device5 Device6 Device7 Device8 TEL- MGT DB DB Can be scaled easily
35. A TANGO Hierarchy Proxy1 Device Server1 Device Server2 Device1 Device2 Device3 Device4 DB Proxy2 Device Server4 Device Server3 Device5 Device6 Device7 Device8 TEL- MGT DB DB Allows for bottom-up building
36. Not talking about… Commonality of attributes (LMC harmonisation) Having similar interfaces for similar devices (inheritance, device libraries, software harmonisation) Archiving and logging Time-stamping Synchronous vs. asynchronous And many others, included in TANGO
37. How much control do you need to dance TANGO? Ability to keep track of own status (state, attributes), and perform “moves” (commands) Ability to measure attributes in others (read attributes) Signal others what is going to happen (write attributes), ask directly (command) Let others define the higher-level of control TANGO rules are embedded throughout
38. Thank you!
39. Questions?
40. TANGO & SKA