Added a section for usage hints, replaced an obsolete interface

CMakeLists.txt

@@ -25,7 +25,7 @@ set(SRC_FILES
     src/rws_interface.cpp
     src/rws_poco_client.cpp
     src/rws_rapid.cpp
-    src/rws_simple_state_machine_interface.cpp)
+    src/rws_state_machine_interface.cpp)
 
 include_directories(include
                     ${Poco_INCLUDE_DIRS}

README.md

@@ -8,13 +8,14 @@
 
 A C++ library for interfacing with ABB robot controllers supporting *Robot Web Services* (RWS). See the online [documentation](http://developercenter.robotstudio.com/webservice/api_reference) for a detailed description of what RWS is and how to use it.
 
-See [abb_libegm](https://github.com/ros-industrial/abb_libegm) for a companion library that interfaces with *Externally Guided Motion* (EGM).
+* See [abb_libegm](https://github.com/ros-industrial/abb_libegm) for a companion library that interfaces with *Externally Guided Motion* (EGM).
+* See [StateMachine Add-In](https://robotapps.robotstudio.com/#/viewApp/7fa7065f-457f-47ce-98d7-c04882e703ee) for an optional *RobotWare Add-In* that can be useful when configuring an ABB robot controller for use with this library.
 
 ### Sketch
 
-The following is a conceptual sketch of how this RWS library can be viewed, in relation to an ABB robot controller as well as the EGM companion library mentioned above.
+The following is a conceptual sketch of how this RWS library can be viewed, in relation to an ABB robot controller as well as the EGM companion library mentioned above. The optional *StateMachine Add-In* is related to the robot controller's RAPID program and system configuration.
 
-![RWS sketch](docs/images/rws_sketch.svg)
+![RWS sketch](docs/images/rws_sketch.png)
 
 ### Requirements
 
@@ -42,11 +43,42 @@ RWS provides access to several services and resources in the robot controller, a
 
 ### Recommendations
 
-* This library has been verified to work with RobotWare `6.06.01`. Other version are expected to work, but this cannot be guaranteed at the moment.
+* This library has been verified to work with RobotWare `6.06.01`. Other versions are expected to work, but this cannot be guaranteed at the moment.
 * It is a good idea to perform RobotStudio simulations before working with a real robot.
 * It is prudent to familiarize oneself with general safety regulations (e.g. described in ABB manuals).
 * Consider cyber security aspects, before connecting robot controllers to networks.
 
+## Usage Hints
+
+This is a generic library, which and can be used together with any RAPID program and system configurations. The library's primary classes are:
+
+* [POCOClient](include/abb_librws/rws_poco_client.h): Sets up and manages HTTP and WebSocket communication and is unaware of the RWS protocol.
+* [RWSClient](include/abb_librws/rws_client.h): Inherits from `POCOClient` and provides interaction methods for using the RWS services and resources.
+* [RWSInterface](include/abb_librws/rws_interface.h): Encapsulates a `RWSClient` instance and provides more user-friendly methods for using the RWS services and resources.
+* [RWSStateMachineInterface](include/abb_librws/rws_state_machine_interface.h): Inherits from `RWSInterface` and has been designed to interact with the aforementioned *StateMachine Add-In*. The interface knows about the custom RAPID variables and routines, as well as system configurations, loaded by the RobotWare Add-In.
+
+The optional *StateMachine Add-In* for RobotWare can be used in combination with any of the classes above, but it works especially well with the `RWSStateMachineInterface` class.
+
+### StateMachine Add-In [Optional]
+
+The purpose of the RobotWare Add-In is to *ease the setup* of ABB robot controllers. It is made for both *real physical controllers* and *virtual controllers* simulated in RobotStudio. If the Add-In is selected during a RobotWare system installation, then the Add-In will load several RAPID modules and system configurations based on the system specifications (e.g. number of robots and present options).
+
+The RAPID modules and configurations constitutes a customizable, ready to run, RAPID program, which contains a state machine implementation. Each motion task in the robot system receives its own state machine instance, and the intention is to use this in combination with external systems that require interaction with the robot(s). The following is a conceptual sketch of the RAPID program's execution flow.
+
+<p align="center">
+  <img src="docs/images/statemachine_addin_sketch.png" width="500">
+</p>
+
+To install the Add-In:
+
+1. Go to the *Add-Ins* tab in RobotStudio.
+2. Search for *StateMachine Add-In* in the *RobotApps* window.
+3. Select the Add-In and retrieve the Add-In by pressing the *Add* button.
+4. Verify that the Add-In was added to the list *Installed Packages*.
+5. The Add-In should appear as an option during the installation of a RobotWare system.
+
+See the Add-In's [user manual](https://robotapps.blob.core.windows.net/appreferences/docs/2093c0e8-d469-4188-bdd2-ca42e27cba5cUserManual.pdf) for more details, as well as for install instructions for RobotWare systems.
+
 ## Acknowledgements
 
 The **core development** has been supported by the European Union's Horizon 2020 project [SYMBIO-TIC](http://www.symbio-tic.eu/).