Embedded System: PIC 16F88, PID Controller - Coursework Example

Embedded system al Affiliation) Key words: PIC 16F88,PID Controller Applications that need temperature measurement and communication system are normally meet in industries. In this report a cheap cost application for temperature measurement and communication system using PIC 16F88 was designed and implemented. In the paper, a temperature sensor is defined as the analog device (TMP04 serial digital TMP04). The designed and implemented PIC 16F88 will also offer digital display of measured temperature using appropriate output. Additionally, the study includes temperature and communication control using a PID controller that is implemented in the microcontroller (Tierney, 2011). Introduction Process control is one of the efficient expressions to improve the process operation, plant productivity, and product’s quality. Currently, demand for efficient temperature and communication has overtook most industrial domain like automotive, alimentary industry, and process heat where temperature control is important in maintaining comfortable surrounding for the occupants. One of the crucial concerns in temperature and communication system is their temperature and communication optimization. Fulfilling such limitation one needs to promote proper control strategies and their implementation. Most researchers have done studies with respect to temperature control and communication system for various processes. In the paper, TMP04 has been interfaced to PIC and output the measured temperatures. Additionally, software has been developed to convert the values of Hex temperature to BCD, and thus offer output to an LCD device (Singh, 2008). Consequently, a program has been developed, implemented, and validated to send the temperature values in a serial format as in the specifications. At the end of the paper, an upgrade to the system is suggested and investigated on how they might be implemented. A mandatory urge in implementing the solution is the development of the software that outlines the complex system’s behavior. The paper focuses in temperature control and model identification in a space designed for PIC 16F88. Discussion The output pulse train of a TMP04 temperature sensor is of nominally thirty five pulses per second in environments that has a temperature of twenty five degrees Celsius. This is where the temperature is expressed as a ratio of high time to low time. This is illustrated as in the equations below Temperature in Degrees Celsius Or Temperature in Fahrenheit In both the above equations, T1 represents high time and T2 represents low time. In cases where there is 0.1 degree resolution, the above written equations can be transformed into; Or In the program written below for interfacing TMp04 to PIC and displaying measured values, T1 and T2 are measured using the PULSIN command. This is illustrated in the code below 1. Interfacing TMP04 to PIC and displaying Measured Values When PIC 16F88 is interfaced with TMP04, the measured temperature will be displayed as outlined in the mat lab code below 2. Conversion of Hex Temperature Value to BCD The user interface consists of a key pad for entering data and LCD for displaying the data. The main menu provides three options; position and temperature control, transmission and conversion, and display of the converted data. When the system is in a control mode, the button can be pressed and moved to indexed positions. The positions are 1, 2, 3, and 4. 1 is zero degrees, 2 are forty degrees, 3 are ninety degrees, and 4 are one hundred and eighty. When the system is in temperature control mode, pressing one will reduce the temperature, pressing two will reverse the temperature, pressing three will increase the temperature, and pressing zero will start the system at the indicated temperature and direction. The TMP04 will be stopped using a different push i.e. a button switch. When in operation and in its control mode, pressing 1 will increase the proportional gain factor while pressing 4 will reduce the gain factor. Conversely, when 3 are pressed, the display will be increased as 6 will increase the display of the temperature sent to the LCD every time a control loop is updated. When # is pressed from the position, temperature or an uprising menu will return the control to the menu. A temperature sensor is used in detecting when a certain key is pressed on the keypad and data is transmitted to PIC 16F88. A second PIC will communicate the conversion to the LCD output. The quadrature counter is used in tracking the TMP04 encoder position. The PIC 16F88 then communicated with 16F84 through start and serial communication channels. The internal oscillator of the system will then be configured (Marwedel, 2006). 4. An upgrade of the system Most applications are dedicated in controlling and measuring temperatures in ideal environment necessary to most needs. Obtaining optimum performance it will be good to offer temperature control and measurement structure by offering a safer heating or safer cooling system with appropriate performance based on flexibility, portability, and efficiency. Extensive studies have been done on heating control due to their necessity in their applications. Here, the paper focuses on process that could be necessary to application in illustrating various control aspects. Additionally, the plant is a cheaper application because their components can be accessed easily. The plant has a resistance, cooler, microcontroller, and sensor which are encapsulated in rooms (Tierney, 2011). The performance of the cooling system can be relieved in order to increase the temperature of the test room using a resistor that is made of a nickel. The discharge of heat in the test room will not change by reducing the current value with an actuation for the alternative current. The cooler will decrease the test room temperature. The microcontroller will then send a communication to the H-bridge which will command the motor to adjust the temperature to a given point. It is mentioned that experiments begins from a given fixed temperature in a room. To minimize the high degree, the current resistor range is reduces by a potentiometer to give 77 degrees Celsius. Here the external source of 220v is used. One of the elements that are active is the cooler. Using a command, the motor will be rotated respecting the control strategy of the motor. The speed of the motor will vary for the motor providing a maximum airflow. The analog sensor is an important transducer. The sensor will operate from negative forty degrees to hundred degrees and here is used in plastic package sensor that considers the basic temperature. With a single degree precision and ability to be calibrated using a resistor, it provides the actual kelvin degrees(Singh, 2008). The degrees will turn to Celsius degrees, to send information to microcontroller. The development board used here is designed for low cost applications with 40 pins. The board contains PIC 16F88 which reduces the consumption of power during use. The computer communication uses a USB cable that is adapted to serial communication with a hardware device called FT232RL. The facility provides the likelihood in establishing connections with a notebook. MDB01 is interfaced with a Dual Full Bridge offering command actions. The bridge driver has a high current, high voltage, and inductive loads such as solenoids, stepper motors, and DC. The enables inputs are offered to disable or enable the machines independently of the signals. Here it is used in single inputting due to a single Direct Current Motor. The lower transistors emitters are connected and external terminals are used in connecting the external resistors. An additional input supply is offered so that the works of the logic are at a reduced voltage. The process has a colored LCD that displays the real-time degrees from sensors. Control System Design In this report, the PID controller parallel form was also implemented. The PIC controller is the time domain is given as E(s) is a signal error, U(s) the process control input, Kp is the proportional gain, Ti is integral time constant, and Td is derivative time constant. The discrete time domain will therefore become In the discreet PID, the variables will be Conclusion In this paper a cheap application for controlling temperature in a temperature and communication system using PIC 16F88 was developed and designed. The laboratory architecture that is proposed in this report enable the users to experiment their knowledge of engineering in a proper way due to processes that can be accessed friendly architecture. The implemented controller on the PIC 16F88 can provide a zero error despite the load disturbance. Where the response of the plant is low, the processor speed could easily be reduced and thus saving power. In future, some of the advanced strategies and their implementation which will show the proper control actions based in the sampling rates will be introduced (Marwedel, 2006) Reference Marwedel, P. 2006. Embedded system design. New York: Springer. Singh, A. 2008. Embedded system. New Delhi, India: Maxford Books. Tierney, S. 2011. 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