Blocklenium

Blocklenium provides a means of starting a remote-controlled browser and running a bookmarklet through a Beckhoff PLC. It was created to control franka emika robots with a web-based user interface using bookmarklets created with blockly-desk. Other uses are not recommended, as it performs some rather specific operations on the loaded website which are characteristic for franka desk.

Prerequisites

This project is intended to run on a Beckhoff IPC with a softPLC supporting ADS running. Also, the following additional Software needs to be installed on the IPC:

• Python >3.6 with PIP
• Chrome Webbrowser
• Selenium Webdriver (See HOWTO-SELENIUM.md for instructions)

Installation

To install on the IPC, download the .zip File from github. Open the cmd.exe command utility and type

    pip install C:\Path\to\blocklenium-master.zip

Make sure that the IPC has a working internet connection. At the end, you should see something like this:

    Successfully installed blocklenium-0.0.1

The installation process creates a command line executable and registers it to the appropriate paths. To test if the installation was successful, type

    blocklenium --help

You should see a list of the command line parameters. The options -b and -u are mandatory (see below).

Intended Use

blocklenium is intended to be started by the PLC, and stay active as long as the PLC is in Run Mode. It will terminate on it's own when it loses contact to the ADS service (i.e. when the PLC is put in Config Mode).

blocklenium requires the PLC to provide a boolean flag GVL.bStartBlockly. The name of the flag can be changed using the command line option --plc_flag. Setting this flag to TRUE on the PLC starts the browser, loads the web page given with the option -u and then runs the bookmarklet.

If desk requires a login, you must include the --login-required flag. blocklenium will then attempt to read the login credentials from the PLC variables GVL.sDeskUsername and GVL.sDeskPassword and enter them in the appropriate fields. If the login page is not displayed, this is ignored.

Creating bookmarklets

When using blockly-desk to create bookmarklets, just drag the finished bookmarklet (marked "V.1" or similar) onto the desktop. This will create a bookmark file with the ending .url. Just pass the path to this file using the command line parameter -b.

If you are writing the bookmarklet in javascript from scratch, you can also save the plain javascript code in a text file with the ending .js or .txt.

Starting from the PLC

Important: blocklenium expects the PLC to be in Run Mode before it is started. If you want to test different command line parameters, make sure that the PLC is running before you start blocklenium.

To start blocklenium from the PLC, use NT_StartProcess, which needs the TC2_Utilities Library enabled on the PLC. See the following example PLC code:

    PROGRAM MAIN
    VAR
        bStartscript : BOOL := TRUE;
        bBusy : BOOL := FALSE;
        Start_py_script : NT_StartProcess;
    END_VAR

    IF bStartscript = TRUE AND bBusy = FALSE THEN
        Start_py_script(
            NETID := '',
            PATHSTR := 'blocklenium',
            DIRNAME := 'C:\Users\Administrator\Desktop',
            COMNDLINE := '-b V.1.url -u http://robot.franka.de',
                START := TRUE,
            BUSY => bBusy
        );
        bStartscript := FALSE;
    END_IF

Please note: The above code only starts the script, but does not yet open the browser. To run the bookmarklet, you must set GVL.bStartBlockly to TRUE.