Industrial Control System - Essay Example

Industrial Control System Student name Institution Course Date ETMEC3260/ENMEC7040 Industrial Systems Control Assignment 2 – semester 2 2014 1. Continuous control Proportional Integral Derivative (PID) Control systems are widely applied in most industries to control various processes through customized algorithms. An instance where PID has been used includes control engineering –steel and chemical processes- to regulate heating, ventilating and air-conditioning (HVAC). The performance of PID controllers is robust and they can operate in a lot of conditions and they are popular since they are simple thereby allowing engineers to work with them in a straightforward manner.. PID makes use of a loop control to manage an operation and the main function is to control identified variables in reference to set point values at an acceptable degree of accuracy and precision. Thus a PID loop is referred to as a mathematical formula that is applied in driving a process variable towards the setpoint (specific value) and try to keep it close to that value though control of the output. As aforementioned, PID loops are widely applied in process-oriented applications for controlling velocity, flow pressure and temperature. For instance in controlling temperature, PID control loop controls the output so as to maintain the desired temperature. This is achieved by comparing feedback from an input to the desired setpoint, reimburses the changes in load for instance cold air influx and thereby adjusting the output accordingly. PID systems can be used to control particular isolated systems or be part of large cascaded systems in which case the input variables or setpoints (National Instruments Corporation, 2014). PID comprises of three main coefficients; proportional (P), integral (I) and derivative (D) that are varied considerably so as to achieve optimal response of the system in control. P coefficient refers to the proportional error (e) at the instant (t) thereby representing ‘present’ error. I coefficient represents the proportional value to the integral of the error at instant t, and it generally taken as the accumulation of the ‘past’ error. D coefficient represents the proportional value to the derivative of the error at instant t which is taken as an estimate of the ‘future’ error. This means that PID controller takes into account the present, the past and the future of the error in order to adjust system parameters accordingly (Opto 22, 2014). In order to understand how PID control works, assume in a heating process; it has a variable y which is the temperature of the liquid, manipulated variable u which is the flow of the fuel. The disturbance would be any factor that influences process variable. Therefore, PID takes into account the disturbances occurring within the systems and calculates the resulting error so as to put the system back to normal. In this instance, a sensor is made use of in measuring the process variable and relay feedback to the control system. It is imperative to note that the command or desired value is the set point. At any instance, the difference between the set point and the process variable is used by the compensator (control system algorithm) so as to establish the actuator output required to drive the system. This is referred to as a closed looped control system as sensors used in reading the systems variables provides consistent feedback. Also, this is the reason it is referred to as a feedback loop system since it involves input, output and feedback based on the outcome. 2. Data gathering hierarchy A corporate hierarchy is important since it involves a multi-tiered information structure in which case data ultimately rolls up to a top level entity. In this case, the hierarchy describes the delineated relationship between the various levels of data and the parent entity as well as users who accesses the data. For instance in a car manufacturing production, it would generally be perceived that distributors or partners would make use of hierarchies to manage complex manufacturing processes and also visualize how each entity relates to each other from a business or a location perspective. A case in point is in franchises where performance evaluation would be necessary. As such, hierarchies with similar data are important for complex system of production. However, distinct groups within a company may at some point require hierarchies of various types. This is because a specific group may consider categorizing customers whereas another other segments them based on products’ preference. On the other hand, sales managers may require grouping them based on geographical purchasing power. This means that all the organization’s data may not be necessary to every person and thus the reason to have hierarchy of data. In particular, benefits that would accrue to an organization that is using multi-tiered hierarchy are for instance: clear visibility –facilitates to capture customers’ view and business strategy; better reporting –enables in creating a connection among various departments; smoother seeling and effective departmental management. ERP in this case would come in handy at integrating all vital business operations, information flows and processes and synergize resources. Programmable logical control (PLC) would be important in automation of mechanical processes and activities being done within the organization’s workshop e.g. assembling. SCADA would be necessary in inductive automation of the systems thereby allowing access of real-time data from any location within the plant. Database systems come in handy at securing safe storage of the data that can be accessed from any functionality within the enterprise (Informatica Corporation, 2013). 5. Selection of controller The best controller to use in this case would be PLC since it is dependent on high-end systematically developed product for industry and is capable of being programmed via high end programming software. Also, the capacity of PLC to be programmed so as to control even simple tasks and pressing on buttons is easy. Also technically, to troubleshoot a PLC system is much easier and friendlier and is more adaptable and changeable. PLC can be interfaced more easily as it is designed for most common machine signals, high speed input, A2D and DC/AC. In the case of micro-controllers, one is required to design his/her interface. In addition, PLC can be expanded infinitely in terms of input/output logical controller that is programmed using and external PC software. Therefore, notably PLC controllers are highly reliable, flexible and fast; capable in handling severe conditions for instance humidity and dust; capable of communicating with several controllers; easily programmed and they have the capacity to display units on real time (Mazidi et al., 2006). Also, for mass production processes, PLCs are more economical to develop and maintain. Importantly to note is that PLCs do have inputs and outputs respectively although they interface at distinct levels. These inputs and outputs are strong and are capable of working in an industrial environment without technical hitches (Petruzella, 2005). As a result, for instance in the case of modifying the combustion system of a vehicle, PLCs are more scalable and capable of being distributed in controlling systems remotely. Also on the other hand, thousands of inputs and outputs can be controlled at the simultaneously regardless of the many types of outputs and inputs that exists. In the case of microcontrollers, they are computer chips only that comprises of inputs and outputs of very low calibre. In that case, in order to control anything with a microcontroller, it requires a lot of work so as to interface it with a system that is being target to be controlled. This is also taking into consideration the low level of programming and also to consider software and hardware of the specific microcontroller that you intend to use. As such, microcontrollers are appropriate for small projects and very cheap. However, in comparison PLC which is standard equipment used in control, they cannot match up (Kumbhar, 2013; Grodzicki, 2010). References Grodzicki, G.P. (2010).Introducing Microcontrollers and PLCS. International Conference on Engineering Education ICEE, pp. 18-22 Informatica Corporation. (2013). Informatica Cloud MDM for Salesforce: Hierarchy Management [online] Available at: Kumbhar, V. (2013). Difference between PLC and Microcontroller?. [online] Availale at: http://plc-scada-dcs.blogspot.com/2013/12/what-is-difference-between-plc-and.html Mazidi, M.A., Mazidi, J.G., McKinlay, R.D. (2006). The 8051 Microcontroller and Embedded Systems Using Assembly and C, 2Ed., New York: Pearson /Prentice Hall. National Instruments Corporation (2014). PID Theory Explained [online] Available at: http://www.ni.com/white-paper/3782/en/ Opto 22. (2014). Proportional Integral Derivative (PID) loop control: What's a PID? [online] Available at: http://www.opto22.com/lp/pid.aspx Petruzella, F.D. (2005). 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