#Simatic siemens step 7 update

Once entered, the program and associated variables are stored in the CPU. The programming device is used to enter and change the PLCвЂ™s program, to monitor and change the stored values. The output modules convert the control signals from the CPU into digital or analog values that can be used to control various output devices.

#Simatic siemens step 7 update

The CPU then sends signals to update the status of the outputs. The CPU evaluates the statuses of the inputs, outputs, and other variables as it executes a stored program.

The primary function of a PLCвЂ™s input circuitry is to convert the signals provided by these various switches and sensors into logic signals that can be used by the CPU.

These analog signals represent machine or process conditions as a range of voltage or current values. Other modules or inputs respond to analog signals. Some input modules or points respond to digital inputs, also called discrete inputs, which are either on or off. The type of the input modules or points used by a PLC depends upon the types of the input devices used. The basic elements of a PLC include input modules or points, a central processing unit (CPU), output modules or points, and a programming device. While the specific applications vary widely, all PLCs monitor inputs and other variable values, make decisions based on a stored program, and control outputs to automate a process or machine. PLCs differ from office computers in the types of tasks that they perform, and the hardware and software they require to perform these tasks. A programmable logic controller (PLC), also referred to as a programmable controller, is the name given to a type of computer commonly used in commercial and industrial control applications.