单片机温度自动控制系统外文文献

1、ign of a temperature controller on a single CY8C27143, 8 pin PSoC chip. As shown in fig.1, it features four main areas: PSoC core, digital system, analog system, and system resources including in/out ports. This architecture allows the user to create customized peripheral configurations that match t

2、he requirements of each individual application. The UART interface, coupled with configurable analog and digital peripherals makes the CY8C27143 truly universal in its connections to the external world. The PSoC core includes: an M8C microcontroller; 32 Kbytes of program flash memory; 2 Kbyte of dat

3、a RAM; internal 24 MHz oscillator; sleep and watchdog timer; general-purpose input/ output pins (GPIO allowing any pin to be used as digital input or output, and most pins to be used as analog inputs or outputs. Every pin can be used as a digital or analog interrupt. The digital system is made up of

4、 8 digital PSoC blocks. Each block is an 8-bit resource that can be used alone or combined with other blocks to form peripherals. Possible peripherals include: PWMs (8-to 32-bit; PWMs with dead band (8-to 24-bit; counters (8-to 32-bit; UART 8-bit with selectable parity; SPI master and slave; cyclica

5、l redundancy checker/generator (8-to 32-bit; pseudo random sequence generators (8-to 32-bit. These digital blocks can be connected to any of the GPIO through a series of global buses. These buses also allow for signal multiplexing and performing logic operations. The analog system is made up of 12 c

6、onfigurable blocks, each comprising an op amp circuit allowing the creation of complex analog signal flows. Analog peripherals J. Jayapandian and Usha Rani Ravi are very flexible and can be customized to support specific application requirements. Some of the more common PSoC analog functions are: fi

7、lters (2-and 4-pole band-pass, low-pass, and notch; amplifiers (up to 2, with selectable gain to 48x; instrumentation amplifiers (1 with selectable gain to 93x; comparators (up to 2, with 16 selectable thresholds; DACs (up to 2, with 6-to 10-bit resolution; and SAR ADCs (up to two, with 6-bit resolu

8、tion. In combination with the digital blocks, additional functions can be created, including: incremental ADCs (up to 2, with 6-to 14-bit resolution; delta sigma ADC (1,with 8-bit resolution at 62.5ksps. The additional system resources provide additional capability useful for the complete system des

9、ign. 3. VIRTUAL INSTRUMENT PROGRAM Virtual instrument (VI is an application of general purpose digital PCs for the measurement and control of various physical variables. The VI program mimics the control processes, which are in a remote area, on the PC screen. On-going process control automation can

10、 be visualized by the experimentalist through PC screen. VI program provides inexpensive and yet a powerful platform for the control and data acquisition of process variables. These programs are easy to implement with graphic languages (G-language. The “G” language implements the data flow technique

11、. The usage of “G” language VIs provides easy interfacing with PCs under the Windows environment 2. The “G” language provides built-in function libraries for a variety of application requirements as graphic palettes, which in turn supports the required DLLs for the functions to run under windows env

12、ironment. Usually the “G” language VI programs consist of two frames viz., panel diagram and functional diagram. In the panel diagram, programmers can assign various controls and indicators (i.e., input and output variables as per their requirements and in the functional diagram, the designers can i

13、mplement the required Fig. 2 : PSoC designer screen for single chip temperature controller An embedded single chip temperature controller design functions available as a function library in LabVIEW. National Instruments LabVIEW version 7.1 incorporates all the necessary functions as icons in its pac

14、kage. 4. PSoC SINGLE CHIP TEMPERATURE CONTROLLER DESIGN Fig.2 shows the PSoC designer screen for the embedded single chip (8 pin PSoC chip CY827143 temperature controller design project 1. Left side of the screen shows the settings of global resource and user module parameters along with pin connect

15、ivity configuration. Middle portion of the screen shows the analog and digital blocks user module placement. Top portion of the screen shows the selected user modules for this project. Right side of the screen describes the pin connectivity configured in the design. In this novel single chip design,

16、 thermocouple (TC signal has been amplified by a programmable gain amplifier (PGA placed in the PSoCs analog block. The amplified TC signal has been fed in to a 12 bit Analog-to digital (ADC user module programmed in the PSoC chip, which includes both analog and digital blocks for its functionality

17、by PSoC designer programming. The converted digital data of the amplified TC signal has been fed to the UART user module for serial communication with Personal Computer. The UART user module placed in the PSoC chip, automatically gets placed in two digital blocks of PSoC chip, transmitter (TxD and r

18、eceiver (RxD for PCs serial communication. A pulse width modulator (PWM, placed in the PSoC digital block, sets a serial pulse width modulated TTL pulses in response to the PID control function for the deviation in set and measured temperature. This will in turn controls the optically coupled solid

19、state relay (SSR driving the AC line power connected to the load/furnace 3,4. The menu driven window based virtual instrument control program senses the temperature, via, thermocouple, TC amplifier, 12-bit ADC and UART communication block of PSoC chip and evaluate the control fu nctions like P,I,D,

20、linear heating, on-sweep and sets the pulse width of PWM in a PSoC chip via UART block in a serial communication. Fig. 3 : Single PSoC chip Temperature controller design J. Jayapandian and Usha Rani Ravi Fig.3. shows the connectivity of a single PSoC chip design with solid state relay (SSR and USB p

21、ort via, serial-to-USB converter cable for communication with PC. The SSR, acts as AC power controller for controlling the furnace power, has been activated by the PWM pulses from PSoC chip. The menu driven virtual instrument control program works in window environment interacts with the embedded de

22、sign for sensing, controlling and acquiring the temperature data. On-line plotting of acquired temperature data also carried out by the VI program. 5. CONCLUSION A simple and cost effective embedded temperature controller has been designed, fabricated and tested successfully for its functionality. This compact designs permits the user to select any type of control func