PLC Hardware Components: PLC Hardware Components – The input and output interface modules consists of an I/0 rack and individual I/O modules. Input interface modules, accept signals from the machine or process devices (120V ac) and convert them into signals (5V dc) that can be used by the controllers. Output interface modules convert controller signals […]
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Basis of PLC Programming: 1.Processor Memory Organisation:The term processor memory organization refers to how certain areas of memory in a given Basis of PLC Programming are used. Different PLC manufacturers organize their memories in different ways. Even though they do not use the same memory make up and terminology, the principles involved are the same.
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PLC Operation: To understand the PLC Operation, consider the simple process shown in Fig. 21.63 In this process a mixer motor is to be used to automatically stir the liquid in a vat when the temperature and pressure reach a preset values. In addition, direct manual operation is also provided by means of a separate
PLC Components: A PLC is a solid state device designed to perform logic functions previously accomplished by electro-magnetic relays. Basically, the PLC Components is an assembly of solid state digital logic decisions which provides outputs. PLCs are used for the control and operation of manufacturing, process equipment and machinery. A typical PLC can be divided
PLC Hardware: PLC hardware falls into the following physical configuration: 1. Fixed Input/ Output (I/O) and 2. Modular I/O. 1.Fixed 1/0 PLCs A fixed PLC Hardware consists of a fixed, or built-in, input/output section. There is one fixed or built-in, non removable screw terminal strip containing all input signal screw terminal connections and another terminal
PLC Basic Process: A PLC Basic Process is basically made up of the following sections, each of which has a unique function to perform in its operation. The sections are: Sensing inputs or controlling hardware PLC input hardware Controller or CPU Hand held programming device or personal computer Output PLC hardware Hardware output devices Sensing
PLC Programming Languages: The term PLC programming languages refers to the method by which the user communicates information to the PLC. The two most common language structures are ladder diagram language and Boolean language. Ladder diagram language is by far the most commonly used PLC Programming Languages.Figure. 21,53, shows a comparsion of the ladder diagram
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Master Control: Master control can be considered the emergency stop switches. An emergency stop switch typically is a big red button on a machine that will shut it off in cases of emergency. It is commonly abbreviated as MC/MCR (Master control / Master Control Reset), MCS/MCR (Master Control Set/Master Control reset) or just simply MCR
AC Input: The, ac input modules that are commonly available work with 24, 48, 110 and 220 V. It is important to use the one that fits the needs based upon the inputs devices (voltage) used. These day, ac input modules are less common than dc input modules. This is because most of the sensors
DC Inputs: The, dc inputs modules commonly available will work with 5, 12, 24 and 48 volts. The DC Inputs modules allow us to connect either PNP (sourcing) or NPN (sinking) transistor type devices to them. If using a regular switch (i.e. a toggle or Push Button, etc.) then it is not important whether it is
