• Journal of the Korea Society of Computer and Information
• /
• v.25 no.6
• /
• pp.17-23
• /
• 2020

In this paper, collecting real-time data frames that occur during RS232 communication between an HMI and PLC of automation equipment by sniffing real-time information data frames through MCU without modification of the HMI or PLC, a method is proposed that allows users to collect data without being dependent on the modification of PLC and HMI systems. The user collects necessary information from the sniffing data through the parsing operation, and the original communication interface is maintained by transmitting the corresponding sniffing frame to the destination. The MCU's UART communication interface circuit is physically designed according to the RS232 communication standard, and this additionally improves efficiency more so than an interrupt-based system by using the DMA device inside the MCU. In addition, the data frame IO operation is performed by logically separating the work of the DMA interrupt service routine from the work of the main thread using the circular queue. Through this method, the user receives the sniffing data frame between the HMI and PLC in RS232 format, and the frame transfer between PLC and HMI arrives normally at the original destination. By sniffing the data frame without further modification of the PLC and HMI, it can be confirmed that it arrives at the user system normally.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.2
• /
• pp.205-211
• /
• 2008

This paper describes the method aimed at establishing the equipment measuring the parameter of Cable Network by Best proper Cable Modem and PDA through RS232 interface. In this paper, we propose our creative experimental configuration and develope the Cable Modem (DOCSIS 2.0) superior more performing than the referred Cable Modem (DOCSIS 1.0, 1.1) and the measuring equipment of HFC network compositing of Cable Modem and PDA through RS232 interface. This equipment analyzes Upstream (U/S) and Downstream (D/S) Signal quality and generates the signal of Upstream by CW signal. The paper also provides the experimental results to check the Best Proper Cable Modem and the displayed screen for parameters for SNR, BER and the demodulated IQ diagram of 256QAM through LCD of PDA. Henceforth, it'll be possible to support a variety of the functions for E-mail, Internet, the speed test of WEB connection and the transmission of the measured result real time by PDA.

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.1295-1297
• /
• 1996

CCITT G.721, G.723 standard ADPCM algorithm is implemented by using TI's fixed point DSP start kit (DSK). ADPCM can be implemented on a various rates, such as 16K, 24K, 32K and 40K. The ADPCM is sample based compression technique and its complexity is not so high as the other speech compression techniques such as CELP, VSELP and GSM, etc. ADPCM is widely applicable to most of the low cost speech compression application and they are tapeless answering machine, simultaneous voice and fax modem, digital phone, etc. TMS320C50 DSP is a low cost fixed point DSP chip and C50 DSK system has an AIC (analog interface chip) which operates as a single chip A/D and D/A converter with 14 bit resolution, C50 DSP chip with on-chip memory of 10K and RS232C interface module. ADPCM C code is compiled by TI C50 C-compiler and implemented on the DSK on-chip memory. Speech signal input is converted into 14 bit linear PCM data and encoded into ADPCM data and the data is sent to PC through RS232C. The ADPCM data on PC is received by the DSK through RS232C and then decoded to generate the 14 bit linear PCM data and converted into the speech signal. The DSK system has audio in/out jack and we can input and out the speech signal.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.337-341
• /
• 1991

Fieldbus is a low level serial digital network which will be used for factory automation. This paper describes lower layer implementation of a Fieldbus network interface. Physical layer provides hardware interface between IBM-PC and Fieldbus. Also, physical layer uses manchester coding, shielded twisted pair lines and RS-485 electrical standard. Data link layer includes Intel's iDCX96 real time executive for 8797 one chip microcontroller and Fieldbus data link protocol software.

• Proceedings of the IEEK Conference
• /
• 2000.06e
• /
• pp.89-92
• /
• 2000

A wire communication module for PLC controller was developed. This system consists of RF module interface part, RS232 serial communication control part, LED display part and control S/W with GUI interface. RF communication frequency is controlled by PLL controlling and communication rate is also controlled as 1200 and 4800 bps. Communication and control status are displayed on LED. As a S/W part, graphic user interface on Window 95 O.S. was developed. To show the validity of the developed system, severial communication and control of PLC system were experemented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.05a
• /
• pp.290-294
• /
• 1999

This paper describes the design and implementation of an intranet-based message and file transfer system using the INMARSAT-C for easy transmission and user-friendly interface. For these, onboard LAN including telex, printer and database with centralized one server is designed and constructed. Also, onboard computing environment which provides the INMARSAT-C terminal and RS-232C link interface built in with effective intranet-based web mail system between the ship and land.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2000.11a
• /
• pp.152-156
• /
• 2000

Many industrial equipments use RS-232C interface. But Ethernet using CSMA/CD was widly spread recently. This interface is not compatible with RS-232C and requires PC based system. So In this Paper, We decribe a Internet control and monitoring system that control and watch plants without PC. We developed IP controller consisted of microprocessor and NIC and monitoring system using VC++ and SQL database. The protocol used this system is UDP/IP because it is applicable for real time system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.11A
• /
• pp.1803-1811
• /
• 2001

In this paper, Forward Error Correction(FEC) that is satisfied with ITU-T Recommendation J.83, Annex B(North American Data Over Cable Service Interface Specifications(DOCSIS) for Multimedia Cable Network System(MCNS)) is analyzed. The FEC consist of Reed-Solomon(RS) layer, interleaving layer, randomization layer, and trellis coded modulation(TCM) layer. The effects of quantization of input symbol and of trace-back depth in the Viterbi decoder are simulated over AWGN channels.

• Journal of Industrial Technology
• /
• v.15
• /
• pp.83-91
• /
• 1995

This paper presents the design of a smart A/D conversion interface used for measuring the load of a truck. Since the load-cell sensor to be used is very sensitive for weight variation, the interface board must have the low-drift and the A/D conversion for accuracy. A new integrator and comparator has been developed to reduce the offset voltage and the drift current of operational amplifiers and has been adapted into the interface board. Also, a software algorithm has been developed to obtain the stable and accrurate A/D conversion. This software includes a RS-485 communication program to control the interface, which gives a capability of backing-up the calibration data and transferring control data. The test and evaluation of the designed interface has been shown as having the better performance compared to the other types of existing weighing systems and sensor instruments.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.515-519
• /
• 2004

A Propeller-Anemometer is an instrument used specifically, to measure the wind speed. The accurate measurement of the wind speed is vitally important such required by any weather stations. In this research, the measurand of the instrumentation was the rotational speed of the propeller and the instrumentation result or output data was wind velocity. The speed measured was recorded digitally in the computer by using specific software. A specific sensor used to measure a variable by converting information of the variable (rotational speed of the propeller) into a dependent signal such as electrical signal in form of voltage. The development of Propeller-Anemometer involved few sets of instrumentation process and equipment. It included three major parts, mechanical, electronics and computer. The main instrumentation processes were physical and signal interfacing, signal conditioning, logic interfacing, data transmission to computer and processing the data. Generally, this paper presents the overall concept and design of Propeller-Anemometer Instrumentation. However, an emphasis was mainly in designing and building the interfacing system, hardware and software. Basically, for the first phase of the development, this project designed and built the RS232 terminal using Peripheral Interface Controller (PIC), PIC16F873. The hardware can be interfaced to computer or other compatible devices. This routine converted input voltage from the circuit to speed (velocity) and transmitted them afterwards to the target device by using the RS232 transmission protocol. This implementation implied a computer display as visual interface. For the purpose of this paper, RS232 data transmission was carried out using a Microsoft Visual Basic software routine.