Start and Stop a PLC Application using a Command Line Tool

This is the process to start and stop a KAS project from an external device (e.g., an HMI) using HTTP communications.

  • This method uses cURL (http://curl.haxx.se), a command line tool for performing HTTP communication with a server.
  • Two HTTP requests are sent:
    • The first request is to authenticate.
    • The second request starts the application. 
curl.exe -X POST -d "username=administrator" -d "password=administrator" -G http://203.0.113.0/authorize/login -c cookie.txt
curl.exe -X PUT http://203.0.113.0/kas/state?newstate=started -b cookie.txt
  • The first request is a POST used to provide credentials to the webserver.
    • The cookie received from the server is stored in a temporary cookie.txt file.
      • This is used in the second request.
    • The username, password, and IP address must be customized for your system.
  • The second request starts the application using a HTTP PUT request.
    • The -b cookie.txt at the end is used to add the authentication cookie received after the first request.
    • The IP address must be customized for your system.

To stop the system, a similar set of commands is used.

curl.exe -X POST -d "username=administrator" -d "password=administrator" -G http://203.0.113.0/authorize/login -c cookie.txt
curl.exe -X PUT http://203.0.113.0/kas/state?newstate=stopped -b cookie.txt

  • cURL exists as a C library.
    It can be used in compiled software which can be used in the HMI.
    If cURL is not an option, equivalent tools can be used if they can POST and PUT HTTP requests and support cookies.

See Also