Real Time Data Acquisition System for Flood Forecasting

Transcription

1 Real Time Data Acquisition System for Flood Forecasting Final Report 6/24/2008 REAL TIME SOLUTIONS PVT. LTD. 58 Samarpan Marg, Tripureshwar P.O. Box No Kathmandu, Nepal Phone: +977 (1) / Fax: +977 (1)

2 Table of Contents Summary... 3 Real Time Data Acquisition System... 4 Real Time Data Acquisition for forecasting flood... 5 Project Description:... 5 Features of the project... 7 Hardware and Software... 8 System Components... 8 Project Activity Preliminary Activities Design Considerations Installation Project Attributes Data Transmission Data Storage Data Representation Conclusion Appendix A System Layout

3 Summary The Real Time Data Acquisition System for flood forecasting incorporates a new technology assembling simple ideas to get effective results. The project implements machine to machine communication using the internet to get information from remote places. This system cuts cost and labor for retrieving data from different places as a remote terminal unit acquires the required data and communicates it to a given server for analysis. The apex advantage of real time data acquisition system is that data is retrieved in real time. The real time data is very crucial for flood forecasting as the areas need to be monitored all the time. The data collected from the sensors giving the rainfall intensity and the water level we can forecast if there may be cases of floods. There are also considerations which defines how the remote terminal unit transmits the data to the server and also how it is represented for further analysis. Using standard protocols for communication the data is stored in a relational database server. This data is further manipulated so that it can be represented in readable format. The user can access the rainfall intensity and the water level by simply clicking on the mapped sites. The data is represented in suitable graphs and charts for easy viewing and can also be specific according to hour, day and month. 3

4 Real Time Data Acquisition System for Flood Forecasting Real Time Data Acquisition System Real time data are highly recognized in fields where many parameters need to be considered in order to obtain a single decision. Supervisory control and data acquisition system (or SCADA system) are widely being used in order to collect data from remote places which involves machine to machine communicatio on for retrieving data. One of key processes of real time data acquisition system is the ability to monitor an entire system in real time. This is facilitated by data acquisitions including meter reading, checking statuses of sensors, etc that are communicated at regular intervals depending on the system. Besides the data being used by the RTU (Remote Terminal Unit), it is also displayed to a human that is able to interface with the system to override settings or make changes when necessary also called the HMI or Human Machine Interface. 4

5 Real Time Data Acquisition System for Flood Forecasting Real Time Data Acquisition for forecasting flood Project Description: The Real Time Data Acquisition System for forecasting flood implements state of the art technology. The remote monitoring and controlling of a system using internet based technology makes it easier to get data from remote and unreachable places and makes it easier for presentation using standard web browsers. The system uses various sensors for detecting rainfall intensity and sensing the water level of the river. These data is first stored in a data logger, which supports CDMA transmission. The data is stored and transmitted at a pre defined interval. The data is transmitted through wireless mediumm over the internet to a database server where it can be analyzed and hosted in the website for general information. Figure: General representation of the Real Time Data Acquisition System for Forecasting Flood 5

6 Real Time Data Acquisition System for Flood Forecasting Figure: Remote Terminal Equipment 6

7 Features of the project This project is intended for collecting the data for the rainfall and the water level for the areas covered by Narayani Basin. The data collected from the mapped sites are to be posted through CDMA over the internet to a database server. The real time data so collected can then be analyzed to get the general information for forecasting flood. Following statements holds the requirements for the area coverage and data collection. All equipments used in this system incorporates state of the art technology (e.g. microcontroller, processors etc) and provide capability for unattended operation for at least one year at remote places using a 12V single sealed maintenance free battery. Ten Rain gauge sites and one water level sensor is interfaced along with the necessary sensors and data logger that supports CDMA transmission. Standard transmission protocol has been implemented. Solar power supply has been arranged for that area where the electricity is inaccessible. All equipment has been able to withstand the hostile environment and well secured against power surge, electrostatic discharge etc. The system has an inbuilt memory that is able to store data for at least one year. In case of failure in transmission through the CDMA module, the system is capable to store necessary backup and will also be possible to retrieve data directly from the site. Error detection and reporting facilities has also been incorporated within the system. 7

8 Real Time Data Acquisition System for Flood Forecasting Hardware and Software System Components Multiple Remote Terminal Units (also knownn as RTUs or Outstations): The RTU connects to physical equipment, and reads status data such as the open/closed status from a switch or a valve, reads measurements such as pressure, flow, voltage or current. RTUs used in the project: The sensors along with the accessories and facilities are completely compatible with the data logger and transmission system specified in the document. All the accessories, tools and fixtures required for the installation and dismounting/ remounting of the equipment has been treated as a part of the supply for each type of sensors. Water Level Sensor: the water level sensor being used is the Steven's A/ F Encoder Model AF 1. General Specification Resolution Output Voltage Levels Power Requirements Environmental At least 1/200 of shaft rotation Minimum high level: 3.5 volts Maximum low level: 0.8 volts Maximum cable length: 250 ft. Voltage Input: 9.6 to 16.0 Volts DC Operating Temperature e: 40 C to 60 C Storage Temperature: 50 to 70 C Humidity: 0 to 100% Rain Gauge: Tipping Bucket Rain Gauge The rain gauge is well capable of gathering and measuring the amount of precipitation over a set period of time with the following specification. The rain collector is designed to meet the guidelines of WMO. 8

9 Real Time Data Acquisition System for Flood Forecasting General Specification Sensor type Minimumm count Output Attached cable length Housing material Dimensions Tipping bucket with magnet reed switch 0.2 mm Contact closure Greater than or equal to 12 m Any non corrosive material Rain collector 500 cm2 or 200 cm2 Communication infrastructure: The remote management or monitoring function of a real time data acquisition system is often referred to as telemetry. This system implements CDMA protocols to transfer data over the internet. General Function The system automatically collects the observations from attached sensors, process the same and store them into its memory as per the pre programmed procedure at every minute and data shall be transmitted over the internet to a database server. The numbers of analog/digital/sdi channels in the data logger are compatible to the sensors being supplied. The sensor's signal conditioning unit is an integral part of the system. Polling rate can be customized by user. Stand alone System ( independent of the PC/Laptop) Stores observed data along with time for all the parameters in the memory. Capacity of memory is capable to retain at least one year s data. Data will be available even if the power supply to the system has failed for one year. The stored data will be transmitted through CDMA transmission. In case of failure of the CDMA module, the stored data can be retrieved via serial port/usb/ethernet to a PC/Laptop or from the storage card. An LCD display for displaying current Date/Time by default and incase of errors show the latest error for one minute A warning system is provided along with the error log including the date and time of failure and also invalid data type. The number of analog/digital/ SDI channels in the data logger will be compatible to the sensors being supplied. Incorporates a watch dog timer. Manages fault of Software. 9

10 System Specification Data Storage Type Size Interface AF Encoder RS232 Backup Battery Real Time Clock Watch Dog Timer Specifications for keeping log Internal Memory (EEPROM) enough to store a month s data Grey Code output Baud Rate: 1200 RS 232 Communication Ports Protocol: RS 232, 8 bit, no parity, 1 stop bit Baud Rate: Programmable enough for 24 hours Internet Synchronized System resets upon microprocessor failure The log kept in the data logger holds the following information for complete analysis of the metrological parameters for flood forecasting (data log) and also the internal working of the devices used in the system. Every log will have time and date stamp except invalid date and time log. The data logger will log following information. System Reset Information Invalid Date and Time Watch Dog Timeout Data from the sensor Timeout o Invalid range o Log for the communication unit Modem not responding o Modem PPP open command not successful o If modem connection not successful o Valid response from the server o Invalid response from the server o If connection close not successful CDMA Scheme The system will be implemented with CDMA transmission module following the given protocol DNS protocol has been implemented to resolve the domain name. Data is being sent using secured HTTP protocol GET or POST method is used for sending/setting the data in the device Latest encryption technology has been used for transmitting data Each unit of information has been separated by a unique character 10

11 Real Time Data Acquisition System for Flood Forecasting Master Station and HMI Computer(s): The database server serves as the master station. It is responsible for communication with the field equipment (RTUs, PLCs, etc) and then to the HMI Software running on workstations in control room or elsewhere. The data collected is being hosted on the website under the flood forecasting. This is the final layout of the data representationn for the flood forecasting. 11

12 Project Activity Preliminary Activities The Real Time Data Acquisition System for Flood Forecasting in Narayani Basin was initiated with an installation of a telerain gauge unit at the Narayani Basin Office in Pokhara on Baisakh After the successful implementation of this unit, the Department of Hydrology and Metrology issued an RFP to implement a Real Time Data Acquisition System for Flood Forecasting in Narayani Basin. The proposal for which was opened on Mangsir The contract was signed on 6th of Falgun Design Considerations The major designing considerations in the Real Time Data Acquisition System are: 1. Sensor and Datalogger communication 2. The devices send rainfall information in terms of tick count which is counted by the server software in mm, and then stored in the database for further analysis. 3. Datalogger function 4. The data is sent at an interval of 5 minutes. 5. All the devices are equipped with LCD displays that constantly display the device status. 6. An error log is also communicated in case of device failure for trouble shooting. 7. The server for posting data is located at 8. To update the water level information using the keyboard, the user has to do the following: a. Press F3 for setting the device into the configuration mode, here the user can change username or password, change data time and other required settings. b. To return to the normal mode the user can press F No, user interaction is required in any of the devices, except for the one installed at the Devghat where the gauge reader height have to be interfaced with the system using a normal computer keyboard to update the water level information 10. Backup power supply in case of power failure and also provision of solar panel where no electricity is available is provided with the RTUs. 12

13 Installation The installation activity for the Real Time Data Acquisition System is scheduled accordingly: Installation Sites Date of Installation 1. Devghat (Naraayni) Installed on 24 th Baisakh Dandi Installed on 24 th Baisakh Arughat Installed on 16 th Jestha Gorkha Installed on 27 th Jestha Beni Installed on 29 th Jestha Angsingh (Dejha, Galyang) Installed on 32 nd of Jestha Pokhara Installed on 30 th of Jestha Jomson Installed on 2 nd Asar Rajaiya Installed on 5 th of Asar Betrawati Installed on 9 th Asar

14 Project Attributes Data Transmission The data transmission is an important part of this project. Special considerations have been implemented to make sure the data are accurate and secure. The following information gives us the basic ideas that are functional in this project. Data is being transmitted using HTTP protocol with POST method in encrypted form AES (128 bit encryption) encryption has been implemented Data packet format to be used for sending information from the Server to the Device DeviceID Project ID Unit log Device ID 4bytes Project ID 4bytes Maximum of 10 number of logs / Minimum 1 logs can be sent at a time. Unit log format Start of Frame Category ID Value Date Time SOF 1 byte Category ID 1 byte (gives the ADC parameters) Value 2 byte Date time 4 byte Data Storage The data from the communication unit form the remote terminals are sent in packets of 16 bytes. These packet data are encrypted using AES encryption. A database is designed to store the raw data from the RTUs. The data is sent at an interval of every 5 minutes. If there is no response from the server while sending the RTU keeps requesting the sever every minute to send the acknowledgement to send the data. Features of Database Server Relational database with at least 1 GB of data storage capacity 99.99% up time guarantee Redundant database server 14

15 Data Representation 1. Encrypted Data (using AES 128) from device 2. Web Server Internet 3. Decryption using secret key 4. Data parsing following specific standard 5. Project determination from parsed data 6. Sorting, evaluating & storing data in database according to its category field in parsed data. Operation performed in web server during data post from device 15

16 Data Represented in the Website The table gives information on the station, rainfall intensity, water level and also the updated time. To view the data for any site you can click on the respective. The data are updated according to the data sent by the devices. The water level is updated every hour. 16

17 Data represented in charts and graphs For each station the data is represented in charts and graphs. You can select the time interval to view the data. You can also select the different modes to represent data i.e. in daily or monthly basis. 17

18 Conclusion The Real Time Data Acquisition System is a necessity for flood forecasting as the data can be collected every 5 minutes from the mapped station. The data collected in real time can save many lives in areas where flood has decimated homes and land along the Narayani Basin. The System also reports on its own performance and can easily detect errors showing efficiency in performance. This project not only protects lives but also opens many possibilities for science to allay mankind s inhibitions. 18

19 Real Timee Data Acquiisition System m for Flood F Forecasting Appendix A m Layout System LLCD Display 2. LCD L Contrast Adjustment 3. Tipping T Buccket Rain Gauge C Connector 4. Tipping T Buckeet LED indicattor 5. A/F A Encodeer (Water Level) C Connector 6. System S LED 7. Internal Batteery C Interface (RS232 2) 8. Computer 9. MMC M Holder (Memory Carrd) 10. Keyboard K Con nnector (PS/2 2) 11. CDMA C Modem m 19 Data Logger L and Communicat C tion Modu ule