Simatic

SIMATIC is a series of programmable logic controller and automation systems, developed by Siemens.

Early SIMATIC devices were transistor-based, intended to replace relays attached and customized to a specific machine.

Microprocessors were introduced in 1973, allowing programs similar to those on general-purpose digital computers to be stored and used for machine control.

Depending on the device and its connection modules, signals may be a simple binary value ("high" or "low") or more complex.

Some systems provided redundant CPU operation for ultra-high-reliability control, as used in pharmaceutical manufacturing, for example.

The introduction of SIMATIC S7 saw also the release of a new fieldbus standard Profibus, and the pioneer use of industrial Ethernet to facilitate communication between automation devices.

The great success of the S7-300 CPU family in particular helped to cement the role of Siemens as one of the global leaders in automation technology.

In addition to STEP 5, Siemens offered a proprietary State logic programming package called Graph5.

STEP 5 allowed the creation of structured or unstructured programming, from simple AND/OR operations up to complex subroutines.