Data Acquisition Technology - Assignment Example

Ques.1 Types of Physical environment: PID controllers are used widely to control- 1. The most common use is- position control of actuators 2. Industrial temperature controllers-eg. controlling temperature of an oven 3. Flow and Level control- eg. Measuring level of hot water tank or boilers 4. Pressure (pneumatic) control- eg. Air pressure control valves in industrial furnaces 5. Speed controlling- eg. Conveyor belt used in bottling plant 6. Position controlling of a motor 7. Power supplies control in heating element 8. Position control of a control valve Meaning of parameters: The fundamental thought behind a PID controller is to peruse a sensor, then figure the required actuator yield by computing proportional, integral, and derivative responses and summing those three parts to register the yield. 1) P: Proportional Response The difference on which the proportional part depends is the difference between the process variable and set point, which is called error term. Kc, the proportional gain is the deciding factor of the proportion of the output response to the error signal. Case in point, suppose the magnitude of the error term is 10, then a proportional reaction of 50 will be created by the proportional gain of 5. Also a rule says that the velocity of the control framework reaction can be built by expanding the proportional gain. On the other hand, if the proportional gain is excessively vast, the process variable will start to sway. On the off chance that Kc is expanded further, the motions will get to be bigger and the framework will get to be shaky and may even sway wild. Fig: basic algorithm-PID control 2) I: Integral Response The integral segment puts together the error term over time. As a result, the integral component can be caused to increase gradually. And this will continue until the error is zero, thus affects the system to make the steady-state error zero. The final difference between the set point and the process variable is called the steady-state error. When the integral action immerses a controller without it making the error signal tending to zero, the phenomenon is called the integral windup. 3) D: Derivative Response if the process variable starts increasing abruptly, the PID component that causes the output to decrease is the derivative component, which is proportional to the rate of change of the process variable. The derivative time (Td) parameter on increasing can cause the strong reaction of the control system to changes in the error term resulting in the increment of the speed of the response of the overall control system. Because of the reason that the derivative response is extremely susceptible to the noise in the process, most practical control systems use very minute derivative time (Td). The control system can be even unstable if there is noise in the sensor feedback signal or if the rate of control loop is too slow. 4) u(t): There is an input, u(t), to the system. Here, 5) y(t): y(t) is the output from the plant after processing input u(t). 6) r(t): this is the input signal from the source or set point in time domain. 7) e(t): this is an error signal generated because of the difference between the input function and the desired output. Here, e(t)= r(t) - y(t) 8) Kp: proportional gain (a tuning parameter) 9) Ki: integral gain (a tuning parameter) 10) Kd: Derivational gain (a tuning parameter) Contribution of each block in overall control objective: 1. Block of Proportionality: in proportional control of a plant whose transfer function does not contains an integrator, there is a steady state error or an offset in the response to a step input. Such an offset can be eliminated if the integral control action is introduced in the controller. 2. Integral block: The integral control action removes offset or steady-state error that may lead to oscillatory response of slowly decreasing amplitude or sometimes even increasing amplitude, both of which are undesirable. In a controller with integral control action, the output of the controller is changed at a rate proportional to the actuating error signal e(t). 3. Block of Derivative control: It anticipates an actuating error and initiates an easily corrective action that leads to the increase in the stability of the system. Derivative control unit when added to the proportionality controller provides a means of obtaining a controller with high sensitivity and advantage of using derivative control action is that it responds to rate of change of actuating error can produce an efficient correction before the magnitude of actuating error becomes too large. 4. Plant or process block: in this block, the input signal u(t) is processed with certain steps to acquire the desired output y(t) out of it. Ques.2 Hierarchy in a car engine: 1) The top most level in hierarchy is ERP, an acronym for Enterprise Resource Planning. ERP is a system which utilizes the machine engineering to make a connection between different facilities, like bookkeeping, stock control and human assets over a entire organization. ERP is projected to promote data offering, business arranging, and choice making on an attempt wide principle. Steps that come under planning the resources are: Item arranging, expense Assembling or administration conveyance Promoting and deals Stock administration Delivery and instalment ERP frameworks track business assets money, crude materials, generation limit and the status of business responsibilities: requests, buy requests, and payroll. The information is offered by the applications that make up the framework over the different offices (assembling, obtaining, deals, bookkeeping, and so on.) that give the data.erp supports data flow between all business capacities, and supervises organizations with outside stakeholders. By and large, there are three sorts of administrations which are accessible to help actualize such changes. They are counselling, customization, and support. Implementation time relies on upon business size, number of modules, customization, the extent of methodology changes, and the preparation of the client to take proprietorship for the venture. An ERP System mechanizes and coordinates centre business methodologies, for example, taking client requests, planning operations, and keeping stock records and monetary information. ERP frameworks can drive enormous enhancements in the viability of any association by: aiding you in characterizing your business courses of action and guaranteeing they are conformed to all through the store network; securing your discriminating business information through decently characterized parts and security access empowering you to arrange your work burden focused around existing requests and figures giving you the instruments to give an abnormal state of administration to your clients making an interpretation of your information into choice making data 2) SCADA: Supervisory control and data acquisition or SCADA is a recent control structure which is at the heart of numerous current businesses, for example, fabricating, vitality, water, power, transportation and a lot more. SCADA frameworks suggest various innovations that authorize associations to screen, assemble, and process information and in addition send signals to those areas that are transmitting information. SCADA frameworks are the spine of cutting edge industry. 3) PLC: A programmable logical controller or a PLC is a computerized machine that is being used for automation of regularly contemporary electromechanical courses of action, for example, we van consider the control of hardware on manufacturing plant sequential construction systems, amusement rides, or light apparatuses. PLCs are utilized as a part of numerous commercial ventures and machines. Huge industry of vehicles assembling needs abnormal state of mechanization, the innovation robotization and items concerned, including movement control, field transport, control items, wellbeing items, discrete sensors, machine vision, and so on. The significant assembling of auto as computerization markets. The car business is the second greatest end client commercial enterprises, second just to the business of metallurgical. The generation line of car is divided into welding, stamping, painting and gathering the four procedures. Each methodology will be far reaching utilization of PLC control, and thusly the most potential for industry of PLC applications, is additionally the lion's share requesting fused innovation FA industry. Case study: Ferrari has been situated in Maranello, Italy since the 1940s. At more than 250,000 square meters, the processing plant's 45 structures house more than 3,000 specialists and consolidate energy, development, and innovation to make the organization's GT and Formula 1 autos. In 1998, Ferrari received Infor Baan IV to backing the primary generation forms for games autos, dashing autos, and extra parts. After twelve years, by moving to Baan's cutting edge item, Infor LN, the organization picked up deeper usefulness while leveraging their long haul venture and transitioning more than 10 years of IT learning without needing to reshape the IT group or its know-how. formula One, where it has revealed in extraordinary accomplishment and also being a designing, outline, and development pioneer in the high execution auto market. Far from the race track, 2011 saw offers of just over 7,000 autos, producing income of € 2.2 billion. The organization stays at the bleeding edge of games and extravagance auto producing and has seen year on year deals development of 7%. Ques.3 PROGRAM 1 PROGRAM 2 PROGRAM 3 Nomenclature: Start PB= Start push button Stop PB= Stop push button MC_EN=machine enable NC_stop pb=stop Push button Safety guard=SF_GD RUN_MC=run machine Chart: Explanation: The block-1, the Transition Block checks if the start button is pressed and MC_EN is 1 or if MC is in Run state. Then, in the block-2 or Step Box, MC should be turned on. It should be turned off if either (NC) stop PB is pressed or safety guard (NC) is active(Block-3). We run this SFC in cyclic execution and stepping mode should be set in T-state, i.e. Transition State. Ques.4 4. Programming the Arduino Using a method of Hardware interrupts and associated interrupt service routines: Void setup() { Attachinterrupt(pin number,interrupt handler function name,rising/falling/high/low); } Void loop() { } Interrupt handler() { */task to be performed/* } Using a method of polled I/O code Void setup() { } Void loop() { If(Pin*==HIGH/LOW) { */task to be performed/* } } Working of each form of coding: A microcontroller can serve various devices. In arduino, certain set of lines are being continuously executed at certain rate by void loop() function. Polling   : In this method what the microcontroller does is it "accesses by himself" the device and “asks” for the information it requires for dealing with. In fact the observation says that the external devices are not independent systems in Polling as they depend on the microcontroller. In this case only the microcontroller is permitted to acquire contact to the information it desires. The microcontroller persistently screens the status of a given gadget. At the point when the condition is reached, it performs the task. After that, it proceeds onward to screen the following gadget until everybody is checked. The microcontroller serves all gadgets in a round robin style. For example: The rx line on the microcomputer constantly surveys for any sign after getting fuelled up. Interrupts: There are some special functions whose execution is based on the priority set by the user. These are called interrupts. Thus, it causes the compiler to hop from void loop function to execute the interrupt statements in arduino. Interrupt is that signal which is sent to the microcontroller to check the occasion that requires prompt consideration. It is "asking for" the processor to stop to perform the current project and to "set aside a few minutes" to execute an exceptional code. At whatever point any gadget needs its administration, the gadget tells the microcontroller by sending it an interrupt. After accepting an interrupt signal, the microcontroller interferes with whatever it is doing and handles the gadget. The system which is connected with the interrupt is known as the interrupt service routine (ISR) or interrupt handler. The most well-known fittings hinders are push catches which can havr signs like RISING, FALLING and so forth. Analogy with door bell : On account of doorbells in the event that we view ourselves as CPU and doorbell as outside gadget, we don't constantly search for door bell; i.e. we don't consistently hold up on the off chance that somebody is pressing doorbell consequently it is not an instance of a surveying yet it acts like an interrupt to our typical routine and we need to go to open the door of the fact that on this time this has more preceding our ordinary work thus this is considered as an interrupt. Benefits of one over the other: In polling, we test the condition again and again inside the loop; whereas in interrupt method, interrupt handler is being called automatically only when it is needed. Benefits of them over one another are: Advantages of interrupts over polling: 1. Whenever, there is a need of the fastest response to any task or event, interrupts are used. For example, if using timer, there is a need to generate a series of pulses, interrupts can be used. When the timer overflows, it calls an interrupt service routine within 1or2 usec to generate the pulse. If instead of interrupt, polling was used, the delay could be more depending upon how often the polling is done and could delay response to several millisecs, which is thousands times slower and the pulse generated is also edgy. 2. Whenever there is a need to keep the power consumption low, interrupts can be used as in many battery powered applications. In such devices, all the clocks are stopped so that the microcontroller is put to sleep resulting in reduced power consumption to a few microamps. Then the controller is awakened from sleep by the interrupts to use power only when required. Certain hand held devices example, TV/VCR remote control are the applications of this concept. Advantages of polling over interrupt: 1. Ta system or a microcontroller has only limited interrupts to use for the peripherals. In that case, not every driver can get an interrupt. So they poll the hardware, i.e., they send a signal to it to acknowledge whether it is ready to transfer data yet. This might be time consuming in some cases, but proves to be helpful sometime. 2. Operations that do not require to be done on a certain exact timing also use polling as by using this microcontroller can be made multitasking. Ques.5 Selection of controller PLC MICROCONTROLLER It works on semi-custom implementation. It is fully general purpose controller. There is hardly any penalty of clock cycles. Interrupt handling requires transfer of control to interrupt handler and hence take certain number of clocks depending upon the microcontroller. It is initially time taking, but will show performance benefits if implemented on a large scale. Its initial implementation is much easier. It has no firmware, hence requires no firmware updates. Firmware can be updated even after the product has been sold to the end user without many complications. To fulfil the expectation of getting a good performance of a car engine, it is necessary to get the precise timing of the supply of current to spark plugs. For this it is very important to keep in mind to choose such a controller for this which does not consume much time. The response from the control system should be quick as well as accurate. Keeping this point in mind, microcontrollers are used for spark-plugging in car engines. This is because; PLCs are used for big and heavy applications which require more memory. Using PLC for this purpose will consume more time for execution as it works by continuously scanning a program. This scan cycle contains three or more steps to perform the allotted task, taking more time in execution. Moreover, the use of interrupts makes the microcontroller more reliable to use. Interrupts can also be used to wake up the microcontroller from a low power sleep state where the processor is halted until necessary to do something by peripheral event in battery operated devices where the power consumption is important. Read More