Traditionally, PLC systems were tightly coupled with dedicated hardware.

Today, control logic can run as software on industrial PCs, servers or virtual machines.

This concept is known as soft PLC or virtual PLC.

Solutions such as Siemens PLC Runtime or Beckhoff TwinCAT allow control systems to run without dedicated PLC hardware.

This approach offers:
greater flexibility
easier scalability
integration with IT systems
better data handling capabilities

Soft PLC is commonly used in:
production lines
logistics systems
data intensive applications
MES and ERP integration

However, it is not suitable for all cases.

In machines where deterministic timing and high reliability are critical, traditional PLCs still have an advantage.

A hybrid approach is becoming more common:
real time control handled by PLC
higher level logic handled by software

Industrial automation is gradually converging with IT.