Microprocessor Based DCS: Microprocessor Based DCS – Modern plants nowadays are very complex, large scale systems with a very high degree of automation. The designs and the operation of these plants are determined by the criteria of economy availability and safety. For example, in thermal power plants, greater unit capacity with higher temperatures and higher …
TDC 3000 Architecture: 1. Hiway Based Distributed Control: The building block concept of TDC 3000 Architecture control design, with distributed process controlled boxes linked together by a communication network, was first introduced by Honeywell in 1975. Today, the monitor and control boxes connected to the Data Hiway as shown in Fig. 21.77 are an integral …
DCS System: A DCS System is preferred over a central computer system for the following reasons. Central Computer System (CCS) exposes the plant to the risk that the system might fail. This can be minimized by having one or more back up schemes. A back up computer Analog controller Manual loading stations Various combinations of the …
Distributed Control System: Distributed Control System – Since the beginning of process control in late 1970s, it has made great progress in every control activity. Similar to the other electronic equipment, its size is decreasing and its power is increasing. The conventional instrumentation is now outdated. The speedy development in the field of electronics has …
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 …
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. …
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 …