Unlike the “Wake-on-LAN”, which is a common standard on computer hardware and uses predefined protocols, the “Sleep-on-LAN” is not predefined and therefore, cannot be relayed on general applications across units from different companies. To use the “Sleep-on-LAN” function you have to install special software on each computer you want to turn off.
Previously when needing to shut down a PC from a control system it was done using AutoShutDown like this. That application is however discontinued now and is not supported anymore.
Now, if a project requires PC shutdown functionality, there are other options available that can be explored to find the option that matches your requirements.
Either of the three below applications can be programmed to to listen either on an TCP/IP server or RS232 and transform that into PC actions like i.e. shutdown the PC or open an application etc.
For turning on the PC, have a look at this article.