Academic literature on the topic 'Microprocessor Based Encoders'

The use of the microprocessor and/or computer for the control of lenses, deflectors, stigmators, camera, gun, accelerating voltage, vacuum system, etc. in the transmission microscope has resulted in improved and simplified operation of the microscope without a consequent sacrifice in the operating flexibility of the TEM. Based on years of experience with electron microscopists, the basic ergonometric design of the microprocessor/computer controlled instrument remains unchanged since the microscopist still has to stradle the microscope in order to operate the stage and apertures. Potentiometers are replaced by rotary encoders, programming of the encoders and of the entire instrument is accomplished by factory upgradable PROMs, and function switches have been added that are uniquely programmable and hence upgradable. Operating simplicity and improved performance were a consequence of the major design consideration, “keep the microscope properly aligned.”Under properly aligned conditions an operator can then easily operate in STEM mode, normal TEM imaging mode, diffraction mode, low mag mode.

This paper presents the design of a bilateral tracing intelligent car based on photoelectric sensors. The control system selects the 16-bit MC9S12XS128 microprocessor as the core controller; employs laser tube and receiving tube to detect the location and movement direction; applies fuzzy self-adaptive PD controller to control the servos; makes use of photoelectric encoder to examine the cars speed. Experimental results indicate that the intelligent car can run along the track steadily and rapidly.

A new low-cost displacement sensing approach is put forward. It employs physical multiplication by using multiple linear encoders and differential grating codestrips, and the differential phase configuration is mechanically guaranteed; furthermore, a flash signal processing circuit comprising time sequence generator, counter and D/A with no microprocessors involved is also developed. Theoretical analysis is presented, and a test system using Heds-9730 as the detecting unit is built, and then experiments on an electromagnetic actuator are carried out. The measured results agreed well with the original, and the results prove that the sensing approach can achieve high sampling rate, high resolution and cost saving, thus providing an effective displacement measuring means for cost-sensitive applications.

A speed control servo system based on STM32 is designed in order to realize the rapid, accurate, smooth speed control of rotary table. the system uses embedded microprocessor STM32F103 as the core, using the absolute encoder as the position sensor.The system achieved control of motor speed by PWM (pulse width modulation).Speed and current double loops control is used,and the expert PID control is used as the control algorithm. Through the analysis of the experimental results can be seen that the system has good stability, and the static and dynamic indicators meet the design accuracy.This design basically has reached the requirement of the servo motor speed control system.

The photoelectric encoder is a kind of encoder that uses high-precision metrology grating as the detection element to convert the input angular position information into corresponding digital signals through the photo-electric conversion device. It has the advantages of high resolution and wide measuring range, so it is widely used in precision angle measuring devices and high-precision speed regulating systems. In this study, an incremental photoelectric encoder is used, and a receiving system of vertical incidence is chosen, covering a photocell receiving circuit and an infrared circuit. The signal acquisition device of the photoelectric encoder is further designed, that is, the weak photoelectric signal is captured and transformed into an electrical signal that can be recognized by the microprocessor after amplification and adjustment, and then the signal is processed and transmitted. In the test, the signal output of the photoelectric encoder is simulated first. The results reveal that the theoretical output voltage of the drive is 3.5 V, and the peak of the actual output signal is 7.2 V, which meets the design requirements. The designed photoelectric encoder signal device is used with the charge coupled device (CCD) camera to capture the track image. The single-camera and dual-camera tests are carried out respectively. The speed of the bearing vehicle is adjusted to 0.6 m/s~1.2 m/s, and the velocity of the vehicle is adjusted timely. The findings show that the signal device of the photoelectric encoder +CCD camera can be triggered in real-time with the different speeds of the vehicle, and obtain relatively clear images of the track surface and its image of the fastener.

A variable rate fertilizer application system with ARM microprocessor as control core was developed. The structure and realization principle of the system were introduced. The system consists of two velocity sensors of photoelectric encoder and proximity transducer, an ARM controller, and an executive unit of stepper motor. The system has automatic and manual variable rate fertilization modes. In the automatic mode, the system can be positioned automatically without GPS, and controls the stepping motor’s rotational speed according to the fertilizing amount in different grid to realize variable rate fertilization. In the manual mode, the controller combines the fertilizing amount in different grid input manually through the keys with the velocity of the applicator, and calculates the stepping motor’s rotational speed to realize the variable rate fertilizer application. The applicator working status can be seen in LCD on the controller. The experimental results show that the system can work properly.

Based on the most significant features of the angular velocity dynamic measurements selected by the authors, the main phases of measuring information transformation were established, which allowed to obtain new mathematical models in the form of transformation function, equations for estimating quantization errors, analytical dependences for measuring range that are initial for modeling physical processes occurring in such digital measuring channels with microprocessor control. The process of converting an analog quantity into a binary code is analytically described, an equation for estimating the absolute and relative quantization error is obtained and a measurement range is established, which provides a normalized value of relative quantization error for angular velocity measuring channels with encoder. For the first time, the equation of sampling error was obtained, and it was proved that the limiting factor of the angular velocity measurements upper limit is not only the normalized value of quantization error, as previously thought, but also the value of sampling frequency fD. Therefore, to expand the measurement range (by increasing the upper limit of measurement), it is proposed not only to increase the speed of analog-to-digital conversion hardware, but also to reduce the execution time of software drivers for transmitting measurement information to RAM of microprocessor system. For this purpose, the analytical dependences of estimating the upper limit of measurement based on the value of the sampling step for different modes of measurement information transmission are obtained. The practical implementation of the software mode measurement information transmission is characterized by a minimum of hardware costs and maximum execution time of the software driver, which explains its low speed, and therefore provides a minimum value of the upper limit measurement. In the interrupt mode, the upper limit value of the angular velocity measurement is higher than in the program mode due to the reduction of the software driver’s execution time (tFl = 0). The maximum value of the angular velocity measurements upper limit can be achieved using the measurement information transmission in the mode of direct access to memory (DMA) by providing maximum speed in this mode (tFl = 0, tDR = 0). In addition, the application of the results obtained in the work allows at the design stage (during physical and mathematical modeling) to assess the basic metrological characteristics of the measuring channel, aimed at reducing the development time and debugging of hardware, software, and standardization of their metrological characteristics.

For improving the generality, expandability and accuracy, the general embedded intelligent monitoring system of tower crane is developed. The system can be applied to different kinds of tower cranes running at any lifting ratio, can be initialized using U disk with the information of tower crane, and fit the lifting torque curve automatically. In dangerous state, the system can sent out alarm signals with sounds and lights, and cut off power by sending signals to PLC through communication interface RS485. When electricity goes off suddenly, the system can record the real-time operating information automatically, and store them in a black box, which can be taken as the basis for confirming the accident responsibility.In recent years, tower cranes play a more and more important role in the construction of tall buildings, in other construction fields are also more widely used. For the safety of tower cranes, various monitors have been developed for monitoring the running information of crane tower [1-8]. These monitors can’t eliminate the errors caused by temperature variations automatically. The specific tower crane’s parameters such as geometric parameters, alarming parameters, lifting ratio, lifting torque should be embedded into the core program, so a monitor can only be applied to a specific type of tower crane, lack of generality and expansibility.For improving the defects of the existing monitors, a general intelligent monitoring modular system of tower crane with high precision is developed, which can initialize the system automatically, eliminate the temperature drift and creep effect of sensor, and store power-off data, which is the function of black box.Hardware design of the monitoring systemThe system uses modularized design mode. These modules include embedded motherboard module, sensor module, signal processing module, data acquisition module, power module, output control module, display and touch screen module. The hardware structure is shown in figure 1. Figure 1 Hardware structure of the monitoring systemEmbedded motherboard module is the core of the system. The motherboard uses the embedded microprocessor ARM 9 as MCU, onboard SDRAM and NAND Flash. Memory size can be chosen according to users’ needs. SDRAM is used for running procedure and cache data. NAND Flash is used to store embedded Linux operating system, applications and operating data of tower crane. Onboard clock with rechargeable batteries provides the information of year, month, day, hour, minute and second. This module provides time tag for real-time operating data. Most interfaces are taken out by the plugs on the embedded motherboard. They include I/O interface, RS232 interface, RS485 interface, USB interface, LCD interface, Audio interface, Touch Screen interface. Pull and plug structure is used between all interfaces and peripheral equipments, which not only makes the system to be aseismatic, but also makes its configuration flexible. Watch-dog circuit is designed on the embedded motherboard, which makes the system reset to normal state automatically after its crash because of interference, program fleet, or getting stuck in an infinite loop, so the system stability is improved greatly. In order to store operating data when power is down suddenly, the power-down protection circuit is designed. The saved data will be helpful to repeat the accident process later, confirm the accident responsibility, and provide the basis for structure optimization of tower crane.Sensor module is confirmed by the main parameters related to tower crane’s security, such as lifting weight, lifting torque, trolley luffing, lifting height, rotary angle and wind speed. Axle pin shear load cell is chosen to acquire lifting weight signals. Potentiometer accompanied with multi-stopper or incremental encoder is chosen to acquire trolley luffing and lifting height signals. Potentiometer accompanied with multi-stopper or absolute photoelectric encoder is chosen to acquire rotary angle signals. Photoelectric sensor is chosen to acquire wind speed signals. The output signals of these sensors can be 0~5V or 4~20mA analog signals, or digital signal from RS485 bus. The system can choose corresponding signal processing method according to the type of sensor signal, which increases the flexibility on the selection of sensors, and is helpful for the users to expand monitoring objects. If the acquired signal is analog signal, it will be processed with filtering, isolation, anti-interference processing by signal isolate module, and sent to A/D module for converting into digital signals, then transformed into RS485 signal by the communication protocol conversion device according to Modbus protocol. If the acquired signal is digital signal with RS485 interface, it can be linked to RS485 bus directly. All the acquired signals are sent to embedded motherboard for data processing through RS485 bus.The data acquisition module is linked to the data acquisition control module on embedded motherboard through RS485 interface. Under the control of program, the system inquires the sensors at regular intervals, and acquires the operating data of crane tower. Median filter technology is used to eliminate interferences from singularity signals. After analysis and processing, the data are stored in the database on ARM platform.Switch signal can be output to relay module or PLC from output control module through RS485 bus, then each actuator will be power on or power off according to demand, so the motion of tower crane will be under control.Video module is connected with motherboard through TFT interface. After being processed, real-time operating parameters are displayed on LCD. The working time, work cycle times, alarm, overweight and ultar-torque information will be stored into database automatically. For meeting the needs of different users, the video module is compatible with 5.7, 8.4 or 10.4 inches of color display.Touch screen is connected with embedded motherboard by touch screen interface, so human machine interaction is realized. Initialization, data download, alarm information inquire, parameter modification can be finished through touch screen.Speaker is linked with audio interface, thus alarm signals is human voice signal, not harsh buzz.USB interface can be linked to conventional U disk directly. Using U disk, users can upload basic parameters of tower crane, initialize system, download operating data, which provides the basis for the structural optimization and accident analysis. Software design of the monitoring systemAccording to the modular design principle, the system software is divided into grading encryption module, system update module, parameter settings module, calibration module, data acquisition and processor module, lifting parameters monitoring module, alarm query module, work statistics module.Alarm thresholds are guarantee for safety operation of the tower crane. Operating data of tower crane are the basis of service life prediction, structural optimization, accident analysis, accident responsibility confirmation. According to key field, the database is divided into different security levels for security requirements. Key fields are grade encryption with symmetrical encryption algorithm, and data keys are protected with elliptic curve encryption algorithm. The association is realized between the users’ permission and security grade of key fields, which will ensure authorized users with different grades to access the equivalent encrypted key fields. The user who meets the grade can access equivalent encrypted database and encrypted key field in the database, also can access low-grade encrypted key fields. This ensures the confidentiality and integrity of key data, and makes the system a real black box.The system is divided into operating mode and management mode in order to make the system toggle between the two states conveniently. The default state is operating mode. As long as the power is on, the monitoring system will be started by the system guide program, and monitor the operating state of the tower crane. The real-time operating data will be displayed on the display screen. At the dangerous state, warning signal will be sent to the driver through voice alarm and light alarm, and corresponding control signal will be output to execution unit to cut off relevant power for tower crane’s safety.By clicking at the mode switch button on the initial interface, the toggle can be finished between the management mode and the operating mode. Under the management mode, there are 4 grades encrypted modes, namely the system update, alarm query, parameter setting and data query. The driver only can browse relevant information. Ordinary administrator can download the alarm information for further analysis. Senior administrator can modify the alarm threshold. The highest administrator can reinitialize system to make it adapt to different types of tower crane. Only browse and download function are available in the key fields of alarm inquiry, anyone can't modify the data. The overload fields in alarm database are encrypted, only senior administrator can browse. The sensitive fields are prevented from being tampered to the great extent, which will provide the reliable basis for the structural optimization and accident analysis. The system can be initialized through the USB interface. Before initialization, type, structural parameters, alarm thresholds, control thresholds, lifting torque characteristics of tower crane should be made as Excel files and then converted to XML files by format conversion files developed specially, then the XML files are downloaded to U disk. The U disk is inserted into USB interface, then the highest administrator can initialize the system according to hints from system. After initialization, senior administrator can modify structural parameters, alarm thresholds, control thresholds by clicking on parameters setting menu. So long as users can make the corresponding excel form, the system initialization can be finished easily according to above steps and used for monitoring. This is very convenient for user.Tower crane belongs to mobile construction machinery. Over time, sensor signals may have some drift, so it is necessary to calibrate the system regularly for guaranteeing the monitoring accuracy. Considering the tower is a linear elastic structure, sensors are linear sensors,in calibration linear equation is used:y=kx+b (1)where x is sample value of sensor, y is actual value. k, b are calibration coefficients, and are calculated out by two-points method. At running mode, the relationship between x and y is:y=[(y1-y0)/(x1-x0)](x-x0)+y0 (2)After calibration, temperature drift and creep can be eliminated, so the monitoring accuracy is improved greatly.Lifting torque is the most important parameter of condition monitoring of tower crane. Comparing the real-time torque M(L) with rated torque Me(L), the movement of tower crane can be controlled under a safe status.M (L)= Q (L)×L (3)Where, Q(L)is actual lifting weight, L is trolley luffing. Me(L) = Qe(L)×L (4)Where, Q e(L) is rated lifting weight. The design values of rated lifting weight are discrete, while trolley luffing is continuous. Therefore there is a rated lifting weight in any position. According to the mechanical characteristics of tower crane, the rated lifting weight is calculated out at any point by 3 spline interpolation according to the rated lifting weight at design points.When lifting weight or lifting torque is beyond rated value, alarm signal and control signal will be sent out. The hoist motor with high, medium and low speed is controlled by the ratio of lifting weight Q and maximum lifting weight Qmax,so the hoisting speed can be controlled automatically by the lifting weight. The luffing motor with high and low speed is controlled by the ratio of lifting torque M and rated lifting torque Me. Thus the luffing speed can be controlled by the lifting torque automatically. The flow chart is shown in figure 2. Fig. 2 real-time control of lifting weight and lifting torqueWhen accidents take place, power will be off suddenly. It is vital for identifying accident liability to record the operating data at the time of power-off. If measures are not taken to save the operating data, the relevant departments is likely to shirk responsibility. In order to solve the problem, the power-off protection module is designed. The module can save the operating data within 120 seconds automatically before power is off suddenly. In this 120 seconds, data is recorded every 0.1 seconds, and stores in a 2D array with 6 rows 1200 columns in queue method. The elements of the first line are the recent time (year-month-day-hour-minute-second), the elements of the second line to sixth line are lifting weight, lifting torque, trolley luffing, lifting height and wind speed in turn. The initial values are zero, when a set of data are obtained, the elements in the first column are eliminated, the elements in the backward columns move frontwards, new elements are filled into the last column of the array, so the array always saves the operating data at the recent 120 seconds. In order to improve the real-time property of the response, and to extend the service life of the nonvolatile memory chip EEPROM-93C46, the array is cached in volatile flip SDRAM usually. So long as power-off signal produces, the array will be shift to EEPROM, at once.In order to achieve the task, the external interruption thread and the power-off monitoring thread of program is set up, the power-off monitoring thread of program is the highest priority. These two threads is idle during normal operation. When power is off, the power-off monitoring thread of program can be executed immediately. When power-off is monitored by power-off control circuit, the external interruption pins produces interrupt signal. The ARM microprocessor responds to external interrupt request, and wakes up the processing thread of external interruption, then sets synchronized events as informing state. After receiving the synchronized events, the data cached in SDRAM will be written to EEPROM in time.ConclusionThe general intelligence embedded monitoring system of tower crane, which can be applicable to various types of tower crane operating under any lifting rates, uses U disk with the information of the tower crane to finish the system initialization and fits the lifting torque curve automatically. In dangerous state, the system will give out the voice and light alarm, link with the relay or PLC by the RS485 communication interface, and cut off the power. When power is down suddenly, the instantaneous operating data can be recorded automatically, and stored in a black box, which can be taken as the proof for identifying accident responsibility. The system has been used to monitor the "JiangLu" series of tower cranes successfully, and achieved good social and economic benefits.AcknowledgementsThe authors wish to thank China Natural Science Foundation(50975289), China Postdoctoral Science Foundation(20100471229), Hunan science & technology plan, Jianglu Machinery & Electronics Co. Ltd for funding this work.Reference Leonard Bernold. Intelligent Technology for Crane Accident Prevention. Journal of Construction Engineering and Management. 1997, 9: 122~124.Gu Lichen,Lei Peng,Jia Yongfeng. Tower crane' monitor and control based on multi-sensor. Journal of Vibration, Measurement and Diagnosis. 2006, 26(SUPPL.): 174-178.Wang Ming,Zhang Guiqing,Yan Qiao,et, al. Development of a novel black box for tower crane based on an ARM-based embedded system. Proceedings of the IEEE International Conference on Automation and Logistics. 2007: 82-87.Wang Renqun, Yin Chenbo, Zhang Song, et, al. Tower Crane Safety Monitoring and Control System Based on CAN Bus. Instrument Techniques and Sensor. 2010(4): 48-51.Zheng Conghai,Li Yanming,Yang Shanhu,et, al. Intelligent Monitoring System for Tower Crane Based on BUS Architecture and Cut IEEE1451 Standard. Computer Measurement & Control. 2010, 18, (9): 1992-1995.Yang Yu,Zhenlian Zhao,Liang Chen. Research and Design of Tower Crane Condition Monitoring and Fault Diagnosis System. 2010 Proceedings of International Conference on Artificial Intelligence and Computational Intelligence. 2010: 405-408.Yu Yang, Chen Liang, Zhao Zhenlian. Research and design of tower crane condition monitoring and fault diagnosis system. International Conference on Artificial Intelligence and Computational Intelligence, 2010, 3: 405-408.Chen Baojiang, Zeng Xiaoyuan. Research on structural frame of the embedded monitoring and control system for tower crane. 2010 International Conference on Mechanic Automation and Control Engineering. 2010: 5374-5377.

SummaryMultivalued logic (MVL) offers higher information density as compared with binary logic systems for an equal number of digits. In a ternary microprocessor, memory access is the most time‐ and power‐consuming action. In order to design a ternary computer, the possibilities for designing ternary encoders and decoders must be examined. This paper presents the designs of 9:2 unbalanced ternary encoder (TENC) and 2:9 unbalanced ternary line address decoder (TDEC) based on novel designs of standard ternary inverter (STI), ternary NAND (TNAND), and ternary NOR (TNOR) logic gates using resistive random‐access memory (RRAM) and carbon nanotube field effect transistor (CNTFET) technology. The simulation results indicate an improvement in performance parameters such as power consumption, delay, power–delay product (PDP), and component count of the proposed circuits in comparison with the different existing counterparts. Moreover, a detailed analysis is carried out on the impact of different process, voltage, and temperature (PVT) variations on the performance metrics, including propagation delay, power consumption, and PDP of the 9:2 unbalanced ternary encoder and 2:9 unbalanced ternary line address decoder. The proposed ternary encoder circuit shows an improvement of 62% in delay, 71% in power consumption, 88.6% improvement in PDP, and 53% reduction in CNTFET count, whereas the ternary decoder circuit exhibits an improvement of 6.6% and 94% in delay and 43% and 94% improvement in power consumption, respectively. Moreover, the CNTFET count is reduced by 16.07% and 46%.

This paper reports a System-on-Chip (SoC) architecture design for the DC-biased optical OFDM (DCO-OFDM) Visible Light Communication (VLC) transceiver. The proposed SoC comprises several Digital Signal Processing (DSP) blocks, i.e., Fast Fourier Transform (FFT), Convolutional Encoder (CE), Viterbi Decoder, Quadrature Phase-Shift Keying (QPSK) Modulator/Demodulator, Interleaver/Deinterleaver, and Synchronizer. System was designed through the combination of two Intellectual Property (IP) types: designing IP from the scratch (custom-based IP) and employing available core accelerator IP served by the third party, which is Xilinx library (reuse-based IP). All DSP blocks were targeted for the FPGA development board (Xilinx Zynq SoC 7000), then combined with the ARM microprocessor. In this study, ARM microprocessors were used for various tasks, i.e., scheduling process, on-chip memory as a temporary data storage function, Analog-to-Digital Converter (A/D), Digital-to-Analog Converter (D/A), and Ethernet module as communication medium between SoCs and personal computer (PC). Testing was carried out on the Register Transfer Level (RTL) for hardware (H/W) and software (S/W) models implemented on ARM microprocessors. The system performances were measured through the point-to-point data communication scenarios between a PC transmitter and PC receiver. A 77 kbps of data communication speed and 2.9 ms of data processing latency were obtained using 100 MHz clock speed. The VLC on-chip was successfully demonstrated in RTL phase. This system is suitable for a low-rate communication system application, generally for joint VLC and Internet-things (IoT) technology, (then called as VLC/IoT).

AbstractTransmembrane G-protein coupled receptors (GPCRs) are ideal drug targets because they resemble, in function, molecular microprocessors for which outcomes (e.g. disease pathways) can be controlled by inputs (extracellular ligands). The inputs here are ligands in the extracellular fluid and possibly chemical signals from other sources in the cellular environment that modify the states of molecular switches, such as phosphorylation sites, on the intracellular domains of the receptor. Like in an engineered microprocessor, these inputs control the configuration of output switch states that control the generation of downstream responses to the inputs.Many diseases with heterogeneous prognoses including, for example, cancer and diabetic kidney disease, require precise individualized treatment. The success of precision medicine to treat and cure disease is through its ability to alter the microprocessor outputs in a manner to improve disease outcomes. We previously established ab initio a model based on maximal information transmission and rate of entropy production that agrees with experimental data on GPCR performance and provides insight into the GPCR process. We use this model to suggest new and possibly more precise ways to target GPCRs with potential new drugs.We find, within the context of the model, that responses downstream of the GPCRs can be controlled, in part, by drug ligand concentration, not just whether the ligand is bound to the receptor. Specifically, the GPCRs encode the maximum ligand concentration the GPCR experiences in the number of active phosphorylation or other switch sites on the intracellular domains of the GPCR. This process generates a memory in the GPCR of the maximum ligand concentration seen by the GPCR. Each configuration of switch sites can generate a distinct downstream response bias. This implies that cellular response to a ligand may be programmable by controlling drug concentration. The model addresses the observation paradox that the amount of information appearing in the intracellular region is greater than amount of information stored in whether the ligand binds to the receptor. This study suggests that at least some of the missing information can be generated by the ligand concentration. We show the model is consistent with assay and information-flow experiments.In contrast to the current view of switch behavior in GPCR signaling, we find that switches exist in three distinct states: inactive (neither off nor on), actively on, or actively off. Unlike the inactive state, the active state supports a chemical flux of receptor configurations through the switch, even when the switch state is actively off. Switches are activated one at a time as ligand concentration reaches threshold values and does not reset because the ligand concentration drops below the thresholds. These results have clinical relevance. Treatment with drugs that target GPCR-mediated pathways can have increased precision for outputs by controlling switch configurations. The model suggests that, to see the full response spectrum, fully native receptors should be used in assay experiments rather than chimera receptors.Inactive states allow the possibility for novel adaptations. This expands the search space for natural selection beyond the space determined by pre-specified active switches.

Most microprocessors and microcontrollers are based on Digital Electronics building Blocks. Digital Electronics gives us a number of combinational and sequential circuits for various arithmetic and logical operations. These include Adders, Subtracters, Encoders, Decoders, Multiplexers, DE multiplexers and Flip Flops. These further combine into higher configurations to perform advanced operations. These operations are done using logic circuits in digital electronics. But in this paper, we explore the human reasoning approach using artificial neural networks. We will look into neural implementations of logic gates implemented with SLP (Single layer perceptron) and MLP (Multi-Layer Perceptron). We will also look into recurrent neural architectures to make basic memory elements, viz. Flip Flops which use feedback and may involve in one or more neuron layers.