We are using the open-source control system framework TANGO in several projects where coordinated control of multiple hardware systems is needed.
What is TANGO good for?
TANGO provides uniform, distributed access and control of heterogeneous hardware devices. It is object-oriented in nature and usually one hardware device is represented by one (or more) software devices.
The device drivers can be written in either C++, Java or Python and client libraries exist for all of these languages. Using a middleware adapter like TangoGQL any language can access the devices.
All that makes TANGO useful for building SCADA systems ranging from a handful controlled devices to several hundreds you want to supervise and control.
Lesser know features of TANGO
All of the above is well known in the TANGO and SCADA community and quite straightforward. What some people may not know is that TANGO automatically provides an Admin-device for each TANGO server (an executable running one or more TANGO devices).
These admin devices have an address of the form dserver/<server_name>/<instance_name> and provide numerous commands for controlling and querying the TANGO device server instance:
You can for example introspect the device server to find available device classes, device instances and needed device properties (think of them as configuration settings).
In addition to introspection you can also control some aspects of the TANGO server like polling and logging. The Admin-device also allows restarting individual devices or even the whole server instance. This can be very useful to apply configuration changes remotely without shell access or something similar to the remote machine.
Wrapping it up
Admin-devices automatically exist and run for each TANGO device server. Using them allows clients to explore what devices are available, what they offer and how they can be configured. They also allow some aspects to be changed remotely at runtime.
We use these features to provide a rich web-base UI for managing the control system in a convenient way instead of relying on the basic tools (like Jive and Astor) that TANGO offers out-of-the-box.
Schneide Blog 