1. Overview

STEP7 SIMATIC is an automation system developed by the German company Siemens. This automation system controls machines used for industrial production and makes it possible for machines to run automatically. This guide provides an overview of SIMATIC STEP 7 and the Edge One™ STEP 7 Client Module.

Simatic, which stands for Siemens and Automatic, is a class of Programmable Logic Controller (PLC) similar to a digital computer, which can store and run programs and that also has inputs and outputs to connect to field machines and sensors. The program running on the Simatic controls these inputs and outputs (I/O’s). I/O’s are connected by electrical wires to the target machine making the communication between the Simatic and any machine possible. As the case requires it, the inputs and outputs are set on a “High” signal or on a “Low” signal by the program. These signals are important if an action in the machine is executed or not.

STEP 7 is the standard software package used for configuring and programming SIMATIC programmable logic controllers. It is part of the SIMATIC industry software. There are the following versions of the STEP 7 Standard package:

  • STEP 7 Micro/DOS and STEP 7 Micro/Win for simpler stand-alone applications on the SIMATIC S7-200.
  • STEP 7 for applications on SIMATIC S7-300/S7-400, SIMATIC M7-300/M7-400, and SIMATIC C7 with a wider range of functions:
    • Can be extended as an option by the software products in the SIMATIC Industry Software (see also Extended Uses of the STEP 7 Standard Package)
    • Opportunity of assigning parameters to function modules and communications processors
    • Forcing and multicomputing mode
    • Global data communication
    • Event-driven data transfer using communication function blocks
    • Configuring connections

This guide describes the general architecture and features of Simatic STEP 7.


Simatic provides bi-directional communication. From the machine to the Simatic and viceversa.

From the Machine to the Simatic

Industrial machines have sensors which provide information about the machines such as how fast a motor rotates, what the temperature is or when the current action is completed. All this information is necessary for the Simatic program. The sensors give out an electrical signal and each signal goes by wire on an input of the Simatic unit. This allows the program to know what is going on in the machine, so that it can perform the next correct step in its sequence. For example, if the temperature of the motor is too high, the program needs to know it in order to switch off the motor.

From the Simatic to the Machine

Industrial machines also have actuators. They are used to cause a wanted motion or action. Examples of actuators are a motor, a heater or a light. If the program says that it is time to switch on the light in the machine, the right output of the Simatic units will be set. This means that an electrical signal at the output goes by wire to the machine and switches the light on.

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The Simatic STEP 7 (S7) product line of Siemens is programmed by the software Step7 or through the TIA (Totally Integrated Automation) portal. Siemens provides the SIMATIC STEP 7 Basic which is software for the configuration of SIMATIC S7-1200 Basic Controllers and the configuration of SIMATIC HMI Basic Panels. It also provides STEP 7 Professional for the programming of PLC’s including S7-1200, S7-1500, S7-300, S7-400, the S7-1500 Software controller, as well as WinAC for PC-based controllers.

For more information, refer to the Siemens Automation Software site.

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Edge One™ STEP 7 Module

The Edge One™ STEP 7 Module allows reading and writing of variables or tags configured in a STEP 7 compatible Siemens PLC.

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Last updated on 6th May 2021