John,

I took this from a Siemens Manual.

WinLC

The Windows Logic Controller (WinLC) is a software package that provides the programmable logic controller (PLC) functionality for the Windows Automation Center (WinAC) Basis package. It is fully compatible with the SIMATIC product family. You can use any of the SIMATIC products, such as the Windows Control Center (WinCC) with WinLC.
WinLC communicates over PROFIBUS-DP to control the distributed I/O, such as ET 200M. WinLC can communicate to STEP 7 or other programming software on another computer over PROFIBUS–DP, Ethernet, or MPI networks.

It is a PC-based logic controller in the family of S7 controllers (S7-300 and S7-400). This controller is fully compatible with the automation tools provided by the SIMATIC family of products, such as the STEP 7 programming software and WinCC. The WinLC controller has four accumulators and supports distributed I/O over a PROFIBUS–DP network. For more information about the operational features of the WinLC,