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1. Data Link Layer Physical Layer Figure 2 Structure of the DLPDU Let us discuss each field one by one Sequence number Sequence number is generally least significant byte of Absolute Slot Number ASN Network ID All the network should be identified using 2 byte network ID Received packet 15 discarded by the device if the network ID of that device does not match with that specified in DLPDU Destination and Source Address WirelessHART supports 2 types of address to the network devices One 15 2 byte long network ID called as nicked name and the other is IEEE EUI 64 address which is 8 byte long DLPDU contains 8 byte long source address if the bit 6 in address specifier field 15 set and 1f bit 2 1s set then DLPDU contains 8 byte long destination address Network manager assigns and manages the 2 byte nick name for each device 2 byte nick name indicates a specific network device or broadcast address 1 e OXFFFF 3 byte of a EUI 64 address consists of a Organizationally unique identifier which 15 assigned by the IEEE Out of remaining 5 bytes 3 bytes are used as device ID and 2 bytes are indicating device type code Device type code 15 allocated by the HCF Destination Address 1 EUI 64 address Source Address 1 EUI 64 address Figure 3 Address Specifier 10 Theoretical background LSB MSB OX1E 0X1B 0X00 lt lt gt gt 44 gt gt 44
2. Yes Read the Value analog from the Process Plant Transmit this data in digital form to the Gateway CAS Figure 14 Flow Chart of Aperiodic sensor task The message is transmitted to the gateway if the conditions become true for the WirelessHART MAC protocol e g current time slot 1s reserved for the destination device and source device defined in the ttWirelessHART MAC arguments to transmit data Before message 15 transmitted type of message 15 also needed to be defined in its message field for the destination device to differentiate easily messages from different devices The message transmitted over the wireless network 15 n the digital form In the third and last segment the execution time of the segment is given I to finish the execution of the entire sensor task 27 Design and Implementation of a simulator Figure 13 and 14 shows the flowchart to configure the sensor devices The flowchart to initialize the sensor device be seen in figure 13 The figure 14 shows the flowchart of the periodic sensor task Gateway Initialization 6 Start Define number of Analog inputs and outputs for the device Create mailboxes for each sensor device to receive data from it Get the array of time slots selected by the user to receive data form sensor devices l Get the array of time slots sel
3. C MyFiles truetime1 5_2 kernel In older versions of MATLAB the setenv command is not available so the environment variable must be defined in the operating system Unix Linux export TTKERNEL DIR kernel Windows use Control Panel System Advanced Environment Variables Then add the following lines to your MATLAB startup m file This will set up all necessary paths to the TrueTime kernel files Getpath getenv TTKERNEL addpath Getpath init truetime 10 Using the Simulator Before we run our simulator we need to provide data through user interface to check the performance of the system with given input data 68 Attachments To input the data open the WirelessSHART Simulator Gui fig file Located at C Documents and Settings SEKUSHA Desktop WirelesSHART Simulator which is a user interface as shown in Fig 40 loj xl File Edit View Insert Tools Desktop Window Help x Number of Super Frames of Super M Number of Sensors Number of Control Loops Number of Actuators Reset Select SuperFrame and TimeSlots for each Sensor Select SuperFrame and TimeSlots for each Actuator Sensor Control Loop Duration Time Slot Act stor SuperFrame start Time Slots SuperFrame SuperFrame D d input Time Slots UR TEE Time Slots Set TimeSlot sa Stan Tine sit Start Time Slot Set TimeSlot Remove Dependency output Remove
4. E Set input output _Remove Health Report gt Remove show TimeSlots in Table Close Figure 40 User Interface Below 15 the description of each user input data field In Fig 1 Starting from the top first user input will be to have the number of Superframes in the network 2 Provide the length of each SuperFrame by selecting the SuperFrame from the popup menu 3 Define the number of sensors in the network Note This input is auto defined but still can be changed 4 Define the number of actuators in the network Note This input is auto defined but still can be changed 5 Define number of control loops in controller 6 Press the Reset button to reset the old values 7 Select the SuperFrame for each sensor and set the time slots for the same sensor 8 Select the SuperFrame for each control loop and set the duration and start of time slot 9 Select the dependency input and dependency output for each control loop 10 Repeat step no 7 for the Actuator 11 Remove button erases the selected timeslots or start of time slot for the each sensor control loop or actuator for specific SuperFrame 12 By pressing the button show TimeSlots in Table shows the reserved slots by each device in each SuperFrame in the table 69 Attachments 13 Health Report button opens the window which shows the status of scheduling method containing error and or collision messages or successful
5. Sensor Signal Gateway Receiver Signal Control signal Gateway Transmitter Signal Actuator Signal 58 Conclusions and Future Work 5 Conclusions and Future Work 5 Conclusions and Limitations 5 1 1 Conclusion and Analysis Test results show that simulator works as per the requirements in chapter 1 4 After defining the size of the network user can assign SuperFrame and link to each network device as per the communication requirements Error and warning messages can be seen for the invalid Input arguments Current simulator supports star topology based network Test results also show that user is able to see the results on the scheduling plot uitable and Health Report window 5 1 2 Key Features of Simulator After defining the size of the network user can assign the SuperFrame and link to each network device as per the communication requirements e Simulator also allows defining the time slot and dependency input as well as dependency output for each control loop Statistics of each time slot of each SuperFrame can be seen on uitable Error and warning messages if any can be seen in detail on Health Report window Each error and warning message type can be seen in different color e nter dependant devices can be seen with the same color on the uitable Network device which are not connected to any control loop can be seen with red color on uitable e Simulator also allows
6. TEKNISKA HOGSKOLAN H GSKOLAN I J NK PING Design and Implementation of a simulator in support of WirelessHART based control systems development Author Kunjesh Shah THESIS WORK 2009 SUBJECT Embedded Systems Electrical Engineering Postal Address Telephone 036 10 10 00 Box 1026 Gjuterigatan 5 551 11 J nk ping TEKNISKA HOGSKOLAN H GSKOLAN I J NK PING Design and Implementation of a simulator in support of WirelessHART based control systems development Author Kunjesh Shah This thesis work is performed at Jonkoping Institute of Technology within the subject area of Embedded Systems within Electrical Engineering The authors are responsible for the given opinions conclusions and results Supervisor Tiberiu Seceleanu ABB Examiner Professor Youzhi Xu JTH Credit points 30 points D level Date Archive number Postal Address Telephone Box 1026 Gjuterigatan 5 551 11 J nk ping 036 10 10 00 1V Acknowledgement Acknowledgement Fist of all I would like to be deeply grateful to efforts of my supervisor in ABB Tiberiu Seceleanu who always followed me with patience and new motivations I would like to express my deep gratefulness and lot of respect to my university J nk ping University School of engineering supervisor Professor Youzhi Xu who followed me with his great vision during my entire master study and allowing me to work with him in summer project as well as suggesti
7. FIGURE 16 FLOW CHART OF EVENT DRIVEN TASK OF GATEWAY RN 30 FIGURE 17 FLOW CHART OF PERIODIC TASK OF GATEWAY Ne 3l FIGURE 18 FLOW CHART TO INITIALIZE THE CONTROLLER 32 FIGURE 19 FLOW CHART PERIODIC TASK OF CONTROLLER RN 33 FIGURE 20 FLOW CHART TO INITIALIZE THE ACTUATOR RN 34 FIGURE 21 FLOW CHART OF EVENT DRIVEN TASK OF ACTUATOR RN 35 FIGURE 22 FLOW CHART PROCESS PLANT WORKING INFORMATION RN 37 FIGURE 23 FLOW CHART OF ONE COMPLETE COMMUNICATION 2 38 FIGURE 24 SCREEN SHOT OF SIMULINK MODEL OF WIRELESSHART BASED NETWORK SYSTEM 39 FIGURE 25 SCREEN SHOT OF INTERNAL DESIGN WNET BLOCK OF SIMULINK MODEL 40 FIGURE 26 FUNCTION BLOCK PARAMETERS OF TRUETIME WIRELESS NETWORK BLOCK 41 FIGURE 27 INTERNAL DESIGN OF PROCESS 42 FIGURE 28 INTERNAL STRUCTURE OF SENSOR NODE OF SIMULINK 43 FIGURE 29 FUNCTION BLOCK PARAMETER FOR SENSOR NODE RN 43 FIGURE 30 SCREEN SHOT OF USER INTERFACE LAY OUT 8 46 FIGURE 31 SCREEN SHOT OF HEALTH REPORT WITH STATUS OF SCHEDULING cct 47 FIGURE 32 SCREEN SHOT OF USER INTERFACE FOR TABLE 3 020 000 0 32 FIGURE 33 SCREEN SHOT OF HEALTH REPORT FOR 3 02020 2 53 FIGURE 34 SCREEN SHOT OF SCHEDULING SIMULINK PLO
8. Table 3 Test Table to show collision Time slot SuperFrame Control Loop Start time slot Dependency input SuperFrame dependency output SI Al S2 2 S3 A3 54 A4 55 5 49 Testing and Results Test table 3 suggests the scheduling of network devices and controller Scheduling of the network devices and the control loops have done such that we be able to see error on uitable on user interface and also on scheduling Matlab simulink scheduling plot Error has intentionally created at time slot 1 and 2 In SuperFrame 1 Table 4 Test Table to show dependency input and output error Time slot SuperFrame M 2212 SuperFrame dependency output Test table 4 suggests the scheduling of the network devices and control loops Scheduling suggestions are given such that we see the dependency input and dependency output error and some warnings as well Table 5 Test Table with right scheduling method Device ID Time slot Transmit receive SuperFrame 50 Testing and Results bene rs Control Loop Start time slot Dependency input SuperFrame dependency output S1 Al 52 A2 a 53 A3 S4 A4 Test table 5 has suggested the scheduling which offers no error and no warnings Scheduling 15 considered as successful when there are no errors and no warnings 4 2 Results 4 2 1 Study the scheduling plots This sub section discusses the results of different test tab
9. bits 245 Transmit power dBm Receiver signal threshold dem 48 Pathloss exponent 1 distance x Special pathloss Function Matlab pathlass Function gt H ACK timeout s 0 000964 Retry limit E Error coding Ehreshald 0 03 Use Fixed Packets Lost Time array s 1500 1503 3000 3004 5000 5005 Cancel Help Apply Figure 26 Function Block parameters of TrueTime Wireless network block Figure 27 1s representing the example of process plant where various kinds of control operations are being performing 41 Design and Implementation of a simulator i untitled Process Plant ial x File Edit wiew Simulation Format Tools Help Math Functions M ath Function M ath Functions 4 k Ready 100 nde45 Figure 27 Internal design of Process Plant Drilling down the any sensor node in schematic diagram designed in Matlab S mulink we get Sub simulink blocks as shown below in Figure 28 TrueTime kernel is the block from the TrueTime Simulink library in which we can define various signals for the node for example analog inputs and outputs Interrupts on external channel wireless message in Rcv wireless message out Snd scheduling plot for the device etc 42 Design and Implementation of a simulator 7Tuntitled Sensor1 B x File Edit view Simulation Format Tools Help 1 0 Normal
10. gt gt gt ret From11 Goto11 Scheduling sensor gateway Controller actuator From12 Soto12 sched Constant1 Controller Figure 24 Screen shot of Simulink model of WirelessHART based network system Figure 24 is the schematic diagram of entire network system with 5 sensors a gateway a controller and 5 actuators Diagram is made in matlab Simulink environment Upper right hand side blocks represent the sensor nodes and they are labeled as sensorl sensor2 sensor5 Upper left hand side blocks represent actuator nodes and are labeled as Actuatorl Actuator2 Actuator5 Block with labeled Wnet is defined more in its low level which is shown in below Figure 25 The TrueTime wireless Network block is the block from the TrueTime simulink library The diagram represents that there are 11 nodes in the network Input signal to the Snd represents wireless signals which are being transmitting All the sensors and the gateway transmits signal over the wireless network which can be seen in the below figure 25 In the figure 25 x y and z can be used to represent the location of each node in 2 D and 3 D the TrueTime wireless Network also allows us to define the amount of noise from the each device in the wireless network output indicates number of signals which has to reach at its destination node through the wireless network Output of the scheduling shows the scheduling of the entire WirelessHA
11. message of current scheduling EET Edit View Insert Tools Desktop Window Help Refresh OK EN Figure 41 Health Report Window Figure 41 shows the Health Report window which contains the status of the current scheduling Refresh button is used to get the latest status of the scheduling button simply closes the window Open the file WirelessHART Simulator mdl located at C Documents and Settings SEKUSHA Desktop WirelessHART Simulator This will look like as shown in below Fig 42 70 WirelessHART_5Simulator Attachments File Edit Yiew Simulation Format Tools Help DIS eel Br gt 2 From1 From2 From4 Froma From10 Display Clock Step f Actuetor2 m Actuetor3 Sensor Dut2 Scheduling sensor gateway Controller actuator Out1 Goto10 Out Sensor imi Figure 42 Simulink Model of Network Design Clicking the icon shown with red round mark in tools window in Fig 2 simulates the user data for the available network type and devices Results can be seen by double clicking on the scope named Scheduling sensor gateway Controller actuator in WirelessHART_S mulator mdl file 71
12. modulation technique with channel hopping on a packet by packet and node by node basis WirelessHART is designed such that it is backward compatible to the existing HART devices which work on the wired communication system WirelessHART uses Time Division Multiple Access TDMA technology at the Data Link Layer to arbitrate and co ordinate communications between the network devices TDMA Data Link Layer specifies the Links by establishing time slots and channel offsets These links are arranged in SuperFrame which are assigned to each network devices and repeated periodically in the same devices Link can be dedicated to assure the delivering of data in guaranteed time slot with minimal latency or shared which allows elastic utilization of communication bandwidth using CSMA CA technique 1 2 1 1 Key Features IEEE STD 802 15 4 compatible physical layer and MAC PDU Designed to satisfy the process automated industrial needs Allows one way to transmit process or control values and two way to accommodate ad hoc request response communications and auto segmented block transfer of large data sets Provides highly secure communication with AES 128 block ciphers and by providing different verification keys 1 e join key Session key and Network key to all the network devices in the field WirelesSHART network devices are exceedingly reliable self healing redundant path mesh networking simple and easy to install and opera
13. 3 Design and Implementation of a simulator This chapter describes the how the actual work 15 being carried out by describing all the phase of work e g architecture design and implementation Testing conclusion and future work Before we start our actual implementation we have put some constraints in our system We are assuming that we have currently star topology in the network and currently there is only one active channel This means all the wireless field devices are only one hop away from the gateway device 3 1 Research Methodology The finishing touch Write the complete Thesis Report Describe interpret data Carry out data collection Plan data collection Plan how to carry out the investigation m Limit problem to specific questions Plan the writing Literature search Choice of topic and delimitation of problem Figure 9 Research Process Research methodology used during the thesis work was same as suggested by Nyberg 2000 Research process can be seen below 19 Design and Implementation of a simulator 3 1 1 Choice of topic and delimitation of problem Before selecting the thesis topic it was necessary to find out the interesting and challenging area for the thesis work Topic chosen for the thesis work was falling under wireless sensor network field which was of course challenging in general and interesting personally as I have already worked in the same area for 4 months in year 2008 Resear
14. D S dp AD 5nd Interruptz Schedule Ground Ivanitors Rew p TrueTime Kernel Ground Terminator Ready 100 lode45 Figure 28 Internal structure of sensor node of simulink model Drilling down the TrueTime kernel block opens the Function Block Parameters for the sensor node can be seen in Figure 29 We can write the name of m file written in Matlab in the field of Name of Init function to configure the node as per our code in the same file Init function argument allows us passing parameter value to the function Battery checkbox field can be checked to track the amount of power remained in the node Clock drift field can be used to define the time drift in the local clock to the reference clock Clock offset field allows us defining the time offset in the local clock to the reference clock Function Block Parameters TrueTime Kernell X Subsystem mask ink Parameters Mame af init Function MEX or MATLAB sensori Init Function argument o oo Battery Clock drift 0 Clock offset gt Cancel Help Apply Figure 29 Function Block parameter for sensor node 43 Design and Implementation of a simulator gateway controller and actuators simulink blocks are the same as defined above for the sensor node 3 4 Design and Implementation of User Interface Before we run the simulink model we need to create user interface to provide various user define
15. be assigned by the function ttInitNetwork Node number handler name Wireless devices can not share the node number in a network Now let us talk about the sensor task which 15 periodically called by the sensor node The period of the sensor task should be no longer than the size of the slot The periodic sensor task first calculates the absolute slot number which gives the current slot number from the start of network simulation The Absolute slot number can be calculated from the following equation AbsSlotNum mod floor Sim_time eps SlotSize SuperframeSize 1 1 S m_time current simulation time SlotSize 0 015 SuperframeSize length of the longest SuperFrame in the network eps execution time of the segment defined more below gt Simulation execution time a Execution of user code Figure 12 The execution of user code is modeled by a sequence of segments executed in order by the kernel The sensor task is executed in segments The segment is incremented after the execution of the current segment The Execution time is given 1 to finish the execution of entire task The execution of the sensor task can be modeled as shown in below Figure 12 25 Design and Implementation of a simulator Sensor Initialization Define number of Analog inputs and outputs for the device Get the array of time slots selected by the user Create a data table cont
16. be seen in the flowchart below 22 Design and Implementation of a simulator Allow user Definining the number of SuperFrame and length of each SuperFrame in the network Allow user Definining the number of sensors actuators and control loops in the network Allow user Definining the dependency input and output for each control loop Allow user assigning time slot for each sensor actuator and control loop in user defined SuperFrame Show status and details of all the time slots of all SuperFrame in the table Show health report describing errors warnings or success of scheduling Figure 11 Architecture of User Interface In above Figure 11 first process block allows the user defining number of SuperFrames and length of each SuperFrame in the network All the SuperFrames are of different length Second process block allows the user defining number of sensors actuators in the network and number of control loops in the controller Third process block allows user defining dependency input sensor id and dependency output actuator 14 for each control loop Dependency input 15 the sensor data from any sensor device for which control signal needs to be calculated Dependency output is the wireless device to which calculated control signal needs to be transmitted Fourth process block allows user scheduling each device
17. but not the controller When there 15 no scheduling of dependency input or dependency output devices for any control loop for each execution e When scheduled device 15 not connected to any control loop 46 Design and Implementation of a simulator teil File Edit View Insert Tools Desktop Window Help NE Device ID or Time slot Ho Device Allocated Device not schedule in the network Device not schedule in the network Device not schedule in the network Device not schedule in the network Device not schedule in the network Device not scheduled in the network Device not scheduled in the network Device not scheduled in the network Device not scheduled in the network Device not scheduled in the network Control loop not scheduled in the network Errors Control loop not scheduled in the network Control loop not scheduled in the network Control loop not scheduled in the network Control loop not scheduled in the network 15 Warnings Figure 31 Screen shot of Health Report with status of scheduling 47 48 Testing and Results 4 Testing and Results 4 1 Testing To test the designed simulator we need to schedule the devices for the communication with each other Simulator has passed through various tests Some of tests are shown here Number of SuperFrame 3 Length of each SuperFrame 15 10 20 40 respectively Number of sensors actuators and control loops 5 Duration of each control loop 1 time slot
18. by the user to receive transmit data to from gateway After collecting the time slot array design the data table matrix defining frame ID channel number destination address communication direction link characteristic for the each time slot Creating interrupt handler and initializing network kernel for the gateway can be done same as sensor node The gateway has two tasks periodic and aperiodic Aperiodic task is event driven When gateway receives any message over the wireless network interrupt to the device occurs and calls the interrupt handler function which wakes up the aperiodic task 29 Design and Implementation of a simulator Gateway as receiver Calculate the Absolute Slot Number urrent Slot is reserved to Receive data Yes Head data received from sensor node from mailbox Write the same data to the controller in analog form Ca Figure 16 Flow Chart of event driven task of Gateway The Gateway as receiver is event driven task of gateway which wakes up when gateway receives any message on the network as defined earlier This task also calculates the Absolute Slot Number as per equation 1 The task is divided in three segments In the first segment we check 1f the time slot is reserved for the gateway receiver If yes then we try to fetch data from the mailbox and in the next segment we write the data to the c
19. friendly 3 1 6 Plan data collection Primary data collections were planned through observations only Error and warning messages were planned to be most visible At the same time timeslot allocation for each interdependent device were also planned to be visible some manner Secondary data collection was done through literature review 3 1 7 Carry out data collection Data were collected through observations only Observation was made on the data from the uitable status from the health report and scheduling plot from Matlab simulink model Observation on uitable and on Health report window was made to see if there any error or warning messages Observation on scheduling plot was made to see if there is any overlap between the two device s execution time and also to see if any packet loss message on the Matlab command prompt during the compilation of current network performance for the given scheduling method 20 Design and Implementation of a simulator 3 1 8 Describe Interpret data Data can be seen on four different screens 1 uitable cell data on User Interface 2 Health report screen 3 scheduling plot and 4 Matlab command prompt Data collected on the User Interface shows which device has reserved which timeslot Moreover device IDs which can be seen in the same colors indicates interdependent devices Health Report screen shows the status of current scheduling method with error and or warning or success messages Each err
20. removing the selected time slot for the device e Reset option is also available to reset the entire SuperFrame for all network device and controller e Each SuperFrame is repeated continuously after finishing its current execution e Length of the longest SuperFrame becomes the number of columns on the uitable Number of superframes in the network defines the number of rows on the uitable 5 1 3 Answers to research questions a How to control the timeslot allocation in WirelessHART network for each network device to have the collision free communications The time slot allocation for each device can be controlled by designing the simulator which provides the statistics of each time slot on User interface explaining each error and warning in detail if any as well as on scheduling plot on simulink model If 59 Conclusions and Future Work simulator finds the successful scheduling method then the same scheduling method can be used for the real physical system b How to configure the WirelessHART network devices in the simulator Configuration of network devices can be done by writing peace of code in Matlab m file and calling required C files of TrueTime Toolbox in the same Matlab m file for each device which defines the nature of the device Configuration of the device contains the information like when to wake up by each device to transmit or receive data over the network and how to proceed to the received data over th
21. RT network Through the Loss signal we can find out the number of lost signal during wireless communication 39 Design and Implementation of a simulator Juntitled Wnet File Edit View Simulation Format Tools Help BR gt r 2 fo FRE de erminatori erminator3 1 52 53 Terminator2 68 54 an ue Terminator4 I 55 i Terminator gt SW Ground Row Schedule sched Terminator Constant3 6 ow loss TrueTime Wireless Network A1 O Nn od Constant Ag Constante d Canang 8 As Constanti1 WER a Constanti2 Constantia Ex a Constantd4 5 Constants Constanti Constant i pA aannmns sfdAmtlt tT GG Constant1O m Figure 25 Screen shot of internal design of Wnet block of simulink model Drilling down the TrueTime Wireless Network block we get the User interface which allows us to choose different network model i e IEEE 802 11 b g or ZigBee or WirelessHART After selecting the network model we can set the different parameters for the network model as shown in the below Figure 26 40 Design and Implementation of a simulator Function Block Parameters TrueTime Wireless Network x Wireless Network maski ink Parameters ai Network type 07867 Network Number 7 Number of nodes pr A Data rate 5 5 290000 Minimum Frame size
22. T FOR TABLE 3 54 FIGURE 35 SCREEN SHOT OF USER INTERFACE FOR TABLE d eee 55 FIGURE 36 SCREEN SHOT OF HEALTH REPORT FOR 4 0 2 0200012 21 55 FIGURE 37 SCREEN SHOT OF USER INTERFACE FOR TABLE SN 56 FIGURE 38 SCREEN SHOT OF HEALTH REPORT FOR TABLE 5 57 FIGURE 39 SCREEN SHOT OF SCHEDULING SIMULINK PLOT FOR TABLE 5 58 BIGURE40 USER INTERFACE 69 FIGURE 41 HEALTH REPORT WINDOWW Nt 70 FIGURE 42 SIMULINK MODEL NETWORK DESIGN RN 71 xli List of Tables List of Tables TABLE Ts THESIS OUTLINE uico uM ee eu LS M E dti 4 TABLE 2 SUMMARY TO INITIALIZE THE NETWORK DEVICES AND CONTROLLER ccc 36 TABLE 3 TEST TABLE TO SHOW COLLISION pp 49 TABLE 4 TEST TABLE TO SHOW DEPENDENCY INPUT AND OUTPUT 50 TABLE 5 TEST TABLE WITH RIGHT SCHEDULING METHOD RN 50 xiii Introduction Introduction This thesis develops the software simulator which simulates the performance of the WirelessHART based wireless communication system WirelessHART is a newly developed industrial standard network by the Hart Communication Foundation HCF which is being currently replacing the existing HART network in the indus
23. Zales NGWO TAG aa 14 2 15 2 2 INTRODUCTION TO TRUETIME SIMULATOR Ne 15 2 3 BASIC PRINCIPLE OF TRUETIME SIMULATION MODEL pp 15 3 Design and Implementation of a simulator 19 Ow RESEARCH METHODOLOGY anne re essen 19 3 1 1 Choice of topic and delimitation Of problem sese eene 20 TL AVUTE E RU LEER 20 Kd EE IG WV UO RR ERROR 20 3 14 Limitproblem to specie Questions ik ee 20 3 20 20 Duc CANOU Cole con Mind eier 20 21 SUUS Write the6ompleie THESIS TOD ONE S ci tae te DS a e aa a a ple ecd SUV ERA RES 21 3 1 10 FS IO nivibus curis deve 21 3 2 ARCHITECTURE OF SCHEMATIC NETWORK DIAGRAM Ne 21 3 3 DESIGN AND IMPLEMENTATION OF NETWORK DEVICES AND USER 24 3 3 1 Configuration of different Network DeyiCceES nnne 24 3 3 2 Simulink model of Network Design eese esses nnne eene nennen ns 39 3 4 DESIGN AND IMPLEMENTATION OF USER INTERFACE 4 2 0 02 0000 01 017 00000000000000000000000000048 44 3 4 1 Algorithm to show Statistics of each timeslot for all SuperFrame on User Interface 44 4 Testing and Results es TING 49 42 ace 51 AS ANG SCHCAUIING ties ide at 51 5 Conclusions and F
24. aining information of channel offset destination address communication direction link characteristic for each time slot l Create a periodic task which periodically senses the value from Process Plant and transmits the same value to the Gateway Create interrupt handler which invokes the periodic task based on defined internal or external events Assign appropriate node number Figure 13 Flow Chart to initialize the Sensor node The sensor task 15 divided into three segments In the first segment we try to read the status of process plant if the time slot 1s reserved by the sensor node And then segment is executed for user defined time The segment 15 incremented when the execution time of current segment 15 finished In the next segment we transmit the data containing status of process plant to the gateway using WirelessHART MAC layer protocol The MAC layer protocol of WirelessHART be used by calling the function ttWirelessHART MAC Arguments to this function are data table matrix 26 Design and Implementation of a simulator which 15 defined in the initialization script destination device address execution time of the case segment and the caller ID in this case current sensor node ID Sensor Task Calculate the Absolute Slot Number urrent Slot is reserved to Transmit data
25. ant working information Figure 23 shows the flowchart of one complete communication cycle starting from the sensor reads data from the process plant to actuator writes the value of control signal to the process plant 37 Design and Implementation of a simulator C START P v Sensor Node reads the process value from the process plant periodically Sensor node transmits the process value to the gateway Gateway receives the process value from the sensor node and writes the same value in analog for to controller Controller reads the analog signal form the Gateway and writes the calculated control signal back to the Gateway Gateway reads the control signal from controller and transmits to the belonged Actuator device Actuator receives the control signal and writes to the Proce Plant Process plant reads the control signal and performs control operation END Figure 23 Flow Chart of one complete communication cycle 38 Design and Implementation of a simulator 3 3 2 Simulink model of Network Design File Edit View Simulation Format Tools Help 0 Bear gt 2 a fio Normal 5 hb SB E Lom H Saturation1 SR Actuetor2 Out In1 Out zn Actuetor4 Out 5 Process Plant Goto10 Senso
26. bered from 1 and upwards as there can be more than one 16 Theoretical background network in the field Wired and wireless networks can not share the same network number Number of nodes defines the number of network devices in one network which determine the size of the Snd Rcv and Schedule input and outputs of the block Data rate bits s the speed of the network Minimum frame size bits determines the minimum length of the message or frame Frame which is shorter than this size will be padded Pre processing delay s the time by which a message is delayed by the network interface on the sending end Post processing delay s the time by which a message is delayed by network interface to receiving end Transmit power determines the strength of the radio signal of transmitting message which defines the maximum range of it Receiver signal threshold medium is accounted busy if the received energy is above this threshold ACK timeout the time for which sending node will wait for ACK signal from the receiver before concluding that packet has been lost and retransmission of message 15 required Error coding threshold determines number in the interval 0 1 which defines the percentage of block errors which the code can handle Path loss exponent is modeled as 1 4 where d is the distance in meters and environment variable which 15 generally between 2 and 4 6 17 18 Design and Implementation of a simulator
27. ch area was restricted to design and implementation of Simulator for WirelessHART based wireless communication system 3 1 2 Literature Search Literature search was mainly not the big part here as the literatures were mainly known We followed the WirelessHART specification documents developed by HCF User manual from Dust Networks and User manual of the TrueTime Simulator These all the documents were used to gain the enough theoretical back ground for our work 3 1 3 Plan the Writing As the work was mainly dependent on the iterative process and results we plan to write the report after finishing the entire work Purpose of writing the report at the end was just to write final most efficient design methods for the simulator 3 1 4 Limit problem to specific questions Task was to design and implement the Simulator in general Purpose of the simulator was limited to provide the way to handle the time slot of each SuperFrame to be used in most efficient way with highly reliable communication between network devices for all available 15 channels in the network Originally created requirements from the simulator can be seen in section 1 3 functional requirements These requirements were further broken down as shown in section 1 4 3 1 5 Plan how to carry out investigation Our research plan was mainly based on iterative process We planned to carry out the investigations in logical and analytical way Simulator was aimed to be most users
28. cles or equipment changing conditions and electromagnetic interference WirelessHART includes several features which are described below in brief Redundant mesh routing space diversity Redundant routing is a must key in real world RF environment Conditions change often in industrial plants due to weather obstacles in the communication path Redundant mesh routing re routes the transmission if it founds the communication path is interrupted to maintain the long term hands off reliability and robustness in the network 4 5 Channel hopping frequency diversity WirelessHART could have suffered from interference from several sources from other networks as in industry generally there exists more than one network which uses the same 2 4 GHZ ISM band WirelessHART avoids this problem by the means of channel hopping which allows choosing dynamically any channel across the 16 channels defined by the IEEE standard 802 15 4 Channel hopping helps to overcome from interference with alertness rather than brute force WirelessHART also offers clear channel assessment and channel black listing to avoid or minimize the interference at specific areas in the WirelessHART as well as in other wireless networks 5 Time synchronized communication time diversity WirelessHART allocates pre scheduled time window to each device in the network for the device to device communication which offers reliable collision free power efficient by avoiding col
29. d inputs to the simulink blocks We thought that the lay out of user interface should be very brief and simple which makes easy for the user to use the simulator Finally we plan to design the user interface which allows user to define sequence of input arguments as following Allow the user to choose number of SuperFrames in the network without any constraints Allow the user to define the length number of time slots of each SuperFrame Allow user to define number of sensors actuators and control loops in the network Allow user to reserve time slots for each sensor in any SuperFrame Allow user to reserve time slots for each actuator in any SuperFrame Allow user to reserve time slots for each control loop in any SuperFrame More than one time slots can be reserved by any sensor actuator or control loop in more than one SuperFrame e There should be also possibility to remove the selected time slots by any device in the network Allow user to define and delete dependency input and dependency output for each control loop Allow user to define the duration time slots of each control loop Allow user to see statistics of time slots in each SuperFrame Allow user to see detailed statistics of over all scheduling errors and warnings by each device in the network User input fields are provided as pop up menu or list box or edit text box In Matlab Guide With the input arguments through the user interface we design
30. defined in second which is used to wake up task periodically function name parameter used to provide the name of function which needs to be called when this task is waken up data is optional if user wishes to pass any parameter to called function Then we need to call the interrupt handler function to handle the event driven interrupts for a node Interrupt handlers may be associated with timers to handle periodic task the network receive channel to handle event 24 Design and Implementation of a simulator driven tasks such as waking up the task when node receives message over the wireless network external interrupt channels when value at any channel changes on wired connection or attached to tasks as overrun handlers To use the interrupt handler function we need to create interrupt handler task define the priority of the function and function name which should be executed when interrupt occurs This can be achieved as following ttCreatelnterruptHandler handler name priority function name In our case for the sensor node we use interrupt handler to wake up the periodic task as it finishes its timer of period It is necessary to provide each node a specific node number This numbers should be in ascending order from the sensor nodes to the gateway and then actuator nodes The gateway and the controller will share the same node number as they are the part of the one device as per the WirelessHART standard Node number can
31. devices offer greatest flexibility and lower installation costs but at the same time as being truly wireless energy usage becomes the constraint to extend the battery life WirelessHART applies two features for device to device and device to user communication to apply low power operation ie Smart Data Publishing and Notification by Exception Smart Data Publishing Smart Data Publishing technique enables transmission of message only when process conditions change or the information is needed by the user s application This avoids unnecessary message transmission and greatly improves the communication requirement as well as power efficiency Notification by Exception Device or process status changes automatically generate notification message to the application 5 2 1 2 Network Architecture Figure 1 shows the typical WirelessHART devices installation architecture WirelessHART specifies three key elements in the wireless network field They are as following Theoretical background Plant Automation Network User 9 Host Application Field Device C Network Manager Handheld Existing HART Devices Adapter Process Automation Controller Figure 1 Elements of the typical WirelessHART Installation WirelessHART Field Devices WED those are connected to the process plant and reads process values from the plant periodically WirelessHART gateway that enables th
32. e 34 below Simulator aborts simulation when there is more than one device try to communicate in the same time slot and this can be also seen from the plot below When more than one device tries to transmit data at the same node or device device receiver drops all packets Number of packet loss at each device can be seen on Matlab command prompt 5 4 5 33 25 0 5 Figure 34 Screen shot of scheduling simulink plot for Table 3 sensor Signal Gateway receiver signal User Interface Error can be seen at the control loop 1 in Figure 35 for the Table 4 Control loop 15 dependant on sensor node 1 and actuator node 2 but both devices are not scheduled So simulator shows error for the scheduling of control loop 1 with the error of dependency input and dependency output 54 Testing and Results ea ER 515 File Edit view Insert Tools Desktop Window Help x Dependency Input error and Dependency Output error Number of Super Frames 3 Length of Super Frame fi 10 Number of Sensors Number of Control Loops 5 Number of Actuators 5 Select SuperFrame and TimeSlots for each Sensor Select SuperFrame and TimeSlots for each Actuator Sensor f Control Loop I z Duration Time Slo 1 Start Time Slots SuperFrame P SuperFrame fi z 2 SuperFrame 51 3 Dependency input S2 E Time Slots 4 54 Time Slots 55 7 3i Set TimeSlot
33. e communication between clients Host Applications and WFDs in the WirelessHART network Gateway supports one or more access points which directly communicate with the WFDs and the gateway WirelesSHART network manager is responsible for the design configuration of the network scheduling forecasting communications between different network devices administration of the routing table monitoring and reporting the health status of the current WirelessHART network periodically There can not be more than one active network manager in the network Network manager may or may not be part of the gateway 1 Theoretical background WirelessHART network supports four OSI layers e g Physical layer Data Link Layer Network Layer and Application Layer They are as following 2 1 2 1 Physical Layer WirelessHART physical layer supports IEEE STD 802 15 4 with the maximum data rate of 250 kbps Operating frequency in WirelessHART is 2400 2483 5 MHZ and applies Direct Sequence Spread Spectrum DSSS modulation technique on information signal Nominal transmission power 15 10 dBM which 15 adjustable in discrete steps Maximum length of the payload data 1s 127 bytes 1 WirelessHART uses radio frequencies to communicate with devices with maximum range of 100 meters with 0 dB transmitting power WirelessHART devices may be either battery powered line powered solar powered or combination of them 2 1 2 2 Data Link Layer Data Link Layer DLL
34. e network or how to transmit data to the desired destination over the network Configuration also contains the interrupt handler functions which can be used to define the event driven activities by the device c What kind of input arguments should be offered by user interface User Interface offers following different arguments to be entered by the user 1 Number of SuperFrames in the network Length of each SuperFrame Number of sensors actuators and control loops in the network IV Allowing user to reserve time slot for any device or control loop on any SuperFrame V Allowing user to define dependency input and output for each control loop d Design the algorithm to get the statistic of each timeslot Results shows that we are able to get the statistics of each time slot on User Interface calculating the latest user input arguments Algorithm has been explained in section 3 4 1 How and what kind of result should be achieved We are able to see two kinds of results one on the User Interface and one on the scheduling plot of simulink model Results on the user interface provide the statistics of each time slot of all Superframes containing the error and the warning messages if any Results on the scheduling plot show the square signal Width of the square signal defines the execution time of that device 5 1 4 Limitations of the simulator Limitations of the simulator 15 that we can see only 10 different colors on
35. ected by the user to transmit control signal data to actuator devices Create a data table containing information of channel offset destination address communication direction link characteristic for each time slot i Create event driven task which wakes up when Gateway receives data from sensor devices Create periodic task which every time checks for the reserved time slot to transmit calculated control signal to the actuator Create interrupt handler which invokes the periodic task based on defined internal or external events I Assign appropriate node number I ent Figure 15 Flow Chart to initialize the Gateway Now let us see the initialization of Gateway which is almost similar to sensor node except few Figure 15 16 and 17 show the flowchart to configure the gateway during the communication 28 Design and Implementation of a simulator Initialization of the gateway be carried out by defining the number of analog inputs and outputs scheduling policy in the ttInitKernel function creating periodic and aperiodic task interrupt handler events etc for the gateway simulation In addition for the gateway initialization we need to create mailbox for each sensor node The mailboxes work as buffer for the device Messages are put in appropriate mailbox based on message type Then collect the time slot array defined
36. een devices 12 We planned to design a simulator which meets the above requirement i e suggesting user network operator with the best possible scheduling method So in the report we will see the methodologies to design and implement the simulator for the industrial automation plant based wireless communication system 1 2 Purpose and aims Purpose of design and implementation of a simulator is to meet the communication requirements of the network devices of the wireless communication system in the most efficient manner for the mesh topology based network Before we move further we realized possible research questions to which we should answer by developing tool for the simulator The possible research questions created are mentioned below How to control the timeslot allocation in WirelessHART network for each network device How to configure the WirelessHART network devices in the simulator What kind of input arguments should be offered by user interface Design the algorithm to get the statistic of each timeslot How and what kind of result should be achieved The user requirements from the simulator are defined below 2 Introduction User Requirements l 2 Allow user defining the size of the network and the placement of each network device on user defined location Calculate the best possible optimized scheduling automatically for the current user arguments and present the result on User interface and on Simul
37. es are involved in the project The SOCRADES project integrates two harmonizing technological approaches e One that focuses on functionality of devices at the lowest level of embedded device hierarchy i e sensors actuators controller gateway etc Major concerns at this level are to provide reliable safe secure and real time communication between network devices One that adopts a service oriented perspective Objectives in this framework are to allow devices to directly communicate amongst themselves as well as with applications to aggregate devices into subsystems and to integrate subsystems with enterprise level applications Automatic contro is a modern way of process and manufacturing industry Traditionally information flows between sensors actuators and control units with hard wired asynchronous communication There has been a transition from communication buses to field bus and Ethernet technologies over the last decade for the control system Currently there 1s a major trend to replace the wired communication system Introduction with newly developed wireless communication system as it is more efficient and offers low cost for installation and commissioning The wireless communication system 15 highly flexible and provides reliable and secure communication between network devices HART communication foundation HCF offers the specification of wireless communication network system which 15 known as WirelessHART Most ind
38. es eu Project Presentation default html 13 Holger Karl Andreas Willig 2007 Protocols and Architectures for Wireless Sensor Networks John Wiley amp Sons Ltd The Atrium Southern Gate Chisester West Sussex POI9 8SQ England John Wiley amp Sons 63 64 Attachments 7 Attachments Attachment 1 User Manual 65 Attachments 66 Attachments USER MANUAL FOR WIRELESSHART BASED WIRELESS COMMUNICATION SYSTEM SIMULATOR 67 Attachments 8 Introduction This manual describes the use of MATLAB Simulink based wireless communication system simulator which uses a WirelessHART MAC layer protocol to communicate with network devices This Simulator facilitates co simulation of controller task execution in real time kernels designed in TrueTime Toolbox network transmissions and continuous plant dynamics The manual describes the required steps in sequence to simulate the desired network performance This includes how to run the simulink file and how to input data through user interface 9 Getting Started 9 Software Requirements Simulator requires MATLAB 6 1 R12 1 or later with Simulink 4 1 or later 9 2 Installation In order to run simulator the environment variable TTKERNEL must be defined to point the directory with the TrueTime kernel files to install TrueTime toolbox inside your computer DIR kernel In later version of MATLAB this can be done using e g the command setenv TTKERNEL
39. estination listens for p start of message Destination ACK starts Cycle n 1 Cycle n Cycle n 1 ee SuperFrame Time slot Figure 7 Data Link Layer SuperFrame At least two devices are associated with the given time slot in unicast communication one at the source end and the other in the destination end A designated destination device remains in the listen mode from the start of dedicated time slot till certain amount of time If device does not listen to any message during that time device goes in sleep mode If the device receives message successfully then it sends back positive acknowledgement to the sender telling message 15 successfully received If the device receives message with some errors then receiver sends acknowledgement signal to the sender telling that message was received with errors 13 Theoretical background Communicating devices are assigned to communication link for the communication Communication link can be formed by assigning SuperFrame time slot direction of the communication transmit receive link characteristic dedicated shared and channel offset All the network devices should support multiple links Number of possible links for each device in the network is number of time slots in SuperFrame multiply by number of channels 15 So if the device has SuperFrame with 100 time slots then number of possible link for the same device is 100 15 1500 links Channel hopping allows having multiple links with differe
40. gt gt Device ID Expanded HCF OUI 0x001B1E Device Type Code Figure 4 Construction of the 8 byte EUI 64 Address DLPDU specifier Priority Packet type 11 Command 000 Acknowledgement 10 Process Data 001 Advertise 01 Normal 001 Keep Alive 00 Alarm 011 Disconnect 111 Data Network Key Figure 5 DLPDU Specifier Figure 3 shows the address specifier field of DLPDU While figure 4 shows the construction of 64 bit long address of each WirelessHART field device First three bits in DLPDU specifier in figure 5 are used to indicate the type of packet type e g Advertise Keep Alive Disconnect and Data Bit 3 15 set to indicate the communication is from the network device which has been authenticated by the confidential network key Fourth and fifth bits are used to show the message priority Bit 6 and 7 are used for future use which should be masked for current use 2 DLL Payload Size of the DLL payload depends on the DLPDU type For example ACK type DLPDU contains the time adjustment information measured by the destination device while data type DLPDU contains the header and payload data for network layer Keyed Message Integrity Code It is used to authenticate DLPDU by the destination device to make sure that DLPDU has been originated from the authenticated network device Cyclic Redundancy Check Theoretical background All data frame contains the 16 bit CRC field which can be represented as shown bel
41. he wired communication system 15 being replacing by the newly developed wireless communication system as it is easy to use scalable simple reliable and provide more flexibility for installing and operating process automation equipments The WirelessHART network is becoming popular for wireless communication system in industrial automation plant system However this network works on the TDMA bus arbitration technique Each network device needs to be scheduled by the user network operator to allow the communications between the field devices and a gateway Some companies like DUST have already manufactured the device hardware to implement this wireless communication system on industrial automation plant A Simulator of this system is necessary to imitate the system performance on computer using the computer programming to simulate the result of each timeslot Purpose of designing this simulator is to use the timeslots more efficiently and to offer collision free communications between network devices It is may be time taking process to build the simulator in the beginning but at the end it provides cost and time effective solutions This report describes how the simulator has been designed for the system at various phases e g architecture design and implementation etc vi Summary Summary Inom Industrial automatiserad process v xter r tradbundna kommunikationssystem som ers tts av den nyutvecklade tradl sa kommunikationssystem som de
42. in body of the thesis work which tries to explain the design and implementation of the simulator as per the functional requirements and provides the flow chart of each network device to initialize them This chapter also includes the schematic diagram of the entire network system and the detail algorithm of User interface Chapter 4 includes the Test tables to test the implemented simulator and also includes results Chapter 5 includes conclusions and some suggested future work on designing simulator as well as discussion regarding the design of User interface and schematic diagram Finally Chapter 6 includes the list of references which are used to carry out the thesis work Chapter 7 lists the attachments Theoretical background 2 Theoretical background This chapter provides the theoretical back ground of WirelessHART network and TrueTime simulator 2 1 WirelessHART network WirelessHART offers network specifications of wireless mesh network for industrial automation process plant application HART Communication Foundation HCF has designed the specification of WirelessHART network to provide the simple reliable and secure wireless communication between wireless devices for the automated process plant industries after the existing HART network which provides wired communication technique between network devices WirelessHART operates in the 2 4 GHZ ISM band at physical layer and utilizes IEEE 802 15 4 standard compatible DSSS radios
43. in the network by assigning time slot on the appropriate SuperFrame Fifth process block allows user having status and 23 Design and Implementation of a simulator details of each time slot of all the SuperFrames on the table Sixth process block allows user having the scheduling information e g successful or errors and or warnings 3 3 Design and implementation of network devices and user interface To start with the design and implementation it is necessary to get use to of programming in TrueTime simulator as we will build our simulator using the platform provided by it TrueTime simulator 15 open source and can be downloading from the source website http www control lth se truetime The TrueTime simulator is more efficient easy to work with capable of simulating complex network system and real time control parameters 6 Can be studied to learn how to write executable code how to configure kernel and network blocks and what compilation needs to be performed to get an executable simulation 3 3 1 Configuration of different Network Devices Keeping the reference of Figure 10 we tried to explore each block in detail This entire subsection 15 the detailed design of Figure 10 In our system four kinds of device exist ie Sensor Gateway Controller and Actuator Each device needs to be initialized before it can be used in the network Initialization of each device can be done as following We will discuss here initializati
44. ink plot From the above user requirements functional requirements can be generated as follows Functional Requirements l 2 Show one way communication between the field devices and gateway with single hop with one channel offset Show one way multi hop communication between field devices and gateway with one channel offset Show two way communications between field devices and gateway with all 15 channel offsets Allow user to choose size of the network and location of each field device Develop algorithm to find the best possible scheduling method based on user defined size of the network and location of the network devices Provide automatically best possible scheduling method on user defined arguments e g size of the network and placement of each field device 1 3 Delimits As the design of the simulator is in the preliminary phase thesis work has been limited to some extent From the above functional requirements requirements from the thesis work have been broken down and limited as follows l 2 Get the theoretical back ground of WirelessHART and hands on experience with the programming on TrueTime simulator Make the simple single hop communication between the field device sensor and gateway and from gateway to field device actuator considering only one channel offset Make single hop communication between more than one field devices sensors and gateway and from gateway to field devices actuators c
45. les Different results can be studied through User Interface uitable Health Report and from the simulink plot 51 Testing and Results Figure 32 Screen Shot of User interface for Table 3 Figure 32 shows the result of scheduling devices as suggested in table 3 As we can see when more than one network devices try to occupy the same time slot we see the Collision message on uitable and also on pop up shown in the screen shot top center We can also see the selected highlighted dependency input and output on the list box for each control loop 52 Testing and Results Health Report As can be seen in the below Figure 33 Health Report describes the error in detail Health report gives the device ID which is involved in causing error and also describes error type and time slot number as well as corresponding SuperFrame number Y File Edit view Insert Tools Desktop Window Help Device ID or Time slot Collision at T amp 1 5F 1 Collision at TS 44 5 1 Collision at TS 24 5 1 OK Collision at TS 34 5F 4 Collision mare than one control loop in one timeslot Collision more than one control loop in one timeslot Collision mare than one control loop in one timeslot Collision mare than one control loop in one timeslot 5 Errors Warnings Figure 33 Screen shot of Health Report for Table 3 53 Testing and Results Scheduling Plot Scheduling plot can be seen in Figur
46. lessHART Technical data sheet 2007 HART Communication Foundation HART Communication Foundation TDMA Data Link Layer HCF_SPEC 075 Revision 1 0 Release date 30 august 2007 Dan Henriksson Anton Cervin Martin Ohlin Karl Erik Arz n TrueTime Real time Control System Simulation with MATLAB Simulink Department of Automatic Control Lund University Sweden Dust Networks 2009 Retrieved July 29 2009 http www dustnetworks com technology technology overview fu redundant mesh routing HART Communication Foundation 2009 Retrieved July 29 2009 http www hartcomm2 org hart protocol applications white paper s why_wirelesshart html Anton Cervin Dan Henriksson Martin Ohlin TrueTime 1 5 Reference Manual Department of Automatic Control Lund University Sweden HART Communication Foundation Network Management Specification HCF_SPEC 085 Revision 1 0 Release date 27 august 2007 Retrieved July 18 2009 http en wikipedia org wiki Media_Access_Control HART Communication Foundation Wireless Devices Specification HCF_SPEC 290 Revision 1 0 Release date 5 september 2007 10 Dust Networks SmartMesh IA 510 MManager XML API Guide Document Number 040 0044 rev 6 SmartMesh IA 510 Manager XML API Guide Revised June 27 2008 11 Nyberg R 2000 Nyberg R 2000 Skriv vetenskapliga rapporter och avhandlingar Studentlitteratur Lund 12 Retrieved August 6 2009 http www socrad
47. lisions and re transmissions and scalable communication promoting interoperability and ease of use Defined priority to each message ensures Quality of Service QoS delivery Fixed time slots enable network manager to create optimal network for any application by self configuration approach without any user intervention Theoretical background DSSS and adjustable power transmission help WirelessHART to provide reliable and power efficient communication even in the presence of other wireless networks 5 2 1 1 2 Security WirelessHART offers highly secured network by applying the industrial standards of security These measures include e Encryption All the messages in the network are being encrypted by 128 bit encryption key before they are sent to transmission medium e Verification Message Integrity Codes verify each packet e Robust Operation Channel hopping and mesh infrastructure alleviate effects of jamming and rejection of service attacks e Key management WirelessHART provides different keys to each device in the network e g network key join key session key to join and communicate in the network These keys are periodically rotating to prevent unauthorized devices from joining the network e Authentication Devices can join the network only with the authorized network ID and join key 5 2 1 1 3 Power WirelessHART offers adjustable transmission power feature to select the best power option for their needs Wireless
48. me kernels and networks as a simulink blocks It is written in C MEX language uses event based simulation and external interrupts TrueTime is a small library of simulation blocks which enhance usability of Matlab Simulink library to simulate discrete network process model User code in the form of tasks and interrupt handlers is modeled by MATLAB or C code which also enables to call simulink block diagrams 6 2 3 Basic principle of TrueTime simulation model To simulate the network model with TrueTime toolbox we should include at least three vital parts of TrueTime toolbox 1 TrueTime kernel which allows initializing each node in the network with the number of VO acquiring network data and processing on acquired data TrueTime kernel is a wit of every device as it realizes a control algorithm for each device in the network This control algorithm can be realized In M file of Matlab There can be more than one task periodic non periodic a kernel and several M files which can cooperate desired target 2 TrueT me network which defines the network model e g 802 11 b g WLAN 15 Theoretical background 802 15 4 ZigBee or WirelessHART etc and its parameters which can be changed 3 Controlled process 3 Library truetime Ioj x File Edit view Format Help DAR 5nd E Interrupts Schedule Manitors E Rew AD TrueTime Kernel pohedule E PE TrueTime Battery noise LOSS signal ttSendMsg Tr
49. nfigure the actuator device during the communication 33 Design and Implementation of a simulator Actuator Initialization CED Define number of Analog inputs and outputs for the device Create a mailbox which receives control signal from the Gateway Get the array of time slots selected by the user Create a data table containing information of channel offset destination address communication direction link characteristic for each time slot Create event driven task which wakes upwhen it receives control signal value from Gateway Create interrupt handler which invokes the periodic task based on defined internal or external events Assign appropriate node number Figure 20 Flow Chart to initialize the Actuator Initialization of actuator is same as the sensor node except actuator has a mailbox and an event driven task to receive data from the gateway Interrupt handler functions same as for the gateway as receiver task Actuator task is also segmented in the three case segments Same as Gateway as receiver task in the first segment actuator task fetches data from the mailbox if the 34 Design and Implementation of a simulator current time slot 15 reserved by the actuator node In the next segment actuator writes data to the process plant in the analog form The process pla
50. ng me to work for the ABB for my master thesis I would also like to express my thanks to my university program coordinator Alf Johansson for giving his all kinds of support and vision during my entire study My special thanks to Mikael Gidlund ABB for his time motivation and new ideas and suggestions during my thesis work I would also like to say my thanks to my colleagues in ABB Saad Dejen Sebastian and Laura for offering their help to me with new ldeas and also being great to me I would like to express my special thanks to entire ABB corporate research who gave me opportunity to work in the amazing work environment I can not go ahead without saying my lot of thanks love and respect to my parents Mayuriben B Shah and Bhupendrakumar R Shah who have always motivated me for my career and also bearing my entire expense till now since my birth the ideal people of my life I would also like to say my thanks from the bottom of my heart to my child hood friend Krishna Darji who has always motivated me for my capabilities and inspiring me all the time to work hard to be great person in the world I would not forget to my sister Jayna R Shah and her entire family for giving me all kinds of support during my master studies Last but not the least my big regards and thanks to entire Sweden for providing such an amazing study environment to the international students Abstract Abstract In Industrial automated process plants t
51. nt channel offsets in the same time slot for different nodes To use the channel hopping feature all the devices in the network should have one common list which provides the list of channel offsets currently in use 2 CSMA CA CSMA CA Carrier Sense Multiple Access with Collision Avoidance protocol uses random delay to reduce the probability of collision Three variables are being used in this protocol e g NB CW and BE NB counts the number of backoffs CW indicates the size of the current congestion window and BE 15 the backoff exponent When any node has data to transmit these variables are initialized for the particular node as 0 CW 2 BE macMinBE respectively Device waits for the r backoff period and listens the channel Clear Channel Assessment CCA If the channel is idle the device decrements CW waits till the next backoff period and senses the channel again If the channel 15 still idle device has won the contention and devices starts transmitting data If either of the CCA operation fails to find the channel idle the numbers of backoffs NB and the backoff exponent BE is incremented and CW 15 set to 2 If the device reaches to maximum number of backoffs device drops the packet and declares a failure in finding the medium All the above steps are repeated on each transmission 13 2 1 3 Network Layer WirelessHART allows full wireless mesh network in which all the devices are able to source sink and r
52. nt performs control operation depending on the received control signal In the third segment actuator task quits Actuator Start gt Calculate the Absolute Slot Number urrent Slot is reserved to Receive data Yes Read the control signal value received from the Gateway form mail box Write the same data to the Process Plant in analog form C Figure 21 Flow Chart of event driven task of Actuator Figure 22 shows the flowchart explaining the function of the process plant during communication Initialization of network devices and controller can be summarized as shown in following table 35 Design and Implementation of a simulator Table 2 to initialize the network devices and controller Controller Get the array of timeslots selected by the user for the device Create a data matrix containing information of DestA dd ChOff LinkDirn LinkChar for each reserved timeslot Interrupt Handler Shares the node number with gateway Process plant reads data from the actuator node performs control operation and writes data to the sensor node 36 Design and Implementation of a simulator Process Plant Read control signal value from the actuator and perform control operation Write the current process data value to the sensor device Figure 22 Flow Chart Process Pl
53. on of each device in True Time simulator one by one Initialization of the device can be carried out by writing peace of code in separate m file for each device To initialize the sensor node in the network we need to define number of analog inputs and outputs for the node and scheduling policy of the function 1 e fixed priority deadline monotonic or earliest deadline first This can be achieved by calling and initializing the function ttInitKernel e g writing ttInitKernel nbrOfInputs nbrOfOutputs scheduling policy Then collect all time slots selected by user for each SuperFrame for the particular sensor node one by one And then define the channel offset destination address communication direction transmit receive link characteristic normal shared and frame ID for each time slot and create a data table matrix containing these all information for the sensor node Create periodic task which wakes up after every 0 01s same as SlotSize by calling the function ttCreatePeriodicTask To call this function we need to define different parameters which are shown below ttCreatePeriodicTask task name offset period prio function name data Let us discuss each parameter one by one task name parameter asks to provide the name to the each task There is no possibility of having same task name in a network offset is the time offset here which can be used to delay the execution of task after it wakes up period 1s
54. onsidering only one channel offset Design and implement the User interface which adds flexibility to the simulator design Design the User interface for the simulink model which allows user to define the size of the network i e number of SuperFrames sensors actuators control loops and to define the communication time slot for each device of interested SuperFrame Show Table which gives the statistics of each time slot of each SuperFrame Show scheduling plot of simulink model with user defined inputs Introduction 1 4 Outline Table 1 Thesis Outline Chap No Key Words Theoretical background WirelessHART Physical layer Data link layer Network layer Application layer Key features Architecture Reliability Security Power TDMA SuperFrame Theoretical background TrueTime tool box Basic principle Network parameters Design and Implementation Schematic diagram Flow chart User Interface Conclusion and future work List of references Attachments Rest of the report 1s constructed as follows Test Tables Results Health Report Scheduling Plot Conclusions and Future work Chapter 2 provides the necessary theoretical back ground of WirelessHART network system describing key features of it advantages and its architectural OSI layers Chapter 2 also provides the theoretical back ground of TrueTime simulator describing basic principle and different network parameters defined by it Chapter 3 provides the ma
55. ontroller to get back the required control signal from the received data value over the network In the third and last segment we finish the execution of the current task 30 Design and Implementation of a simulator Gateway as Transmitter Calculate the Absolute Slot Number urrent Slot is reservec to Transmit data 2 Yes Read analog data from controller Transmit this data to the appropriate actuator device um Figure 17 Flow Chart of periodic task of Gateway The Gateway as transmitter is the periodic task of the gateway which wakes up after every 0 015 It is segmented same as defined for the sensor task The Gateway as transmitter task reads data from controller and transmits it to the either of Actuator nodes Initialization of the controller is same as the sensor node except that the controller shares the node number with gateway 31 Design and Implementation of a simulator Controller Initialization Define number of Analog inputs and outputs for the device Get the array of start time slot for each control loop selected by the user Create a periodic task which periodically wakes up and check for the reserved time slot to read data from Gateway and to write calculated control signal value to the Gateway itself Create interrupt handler which invokes the periodic task based on defined inte
56. or can be seen in detail in this screen Moreover each error type has been shown in different colors so the debugging of error messages becomes easy Warning messages has been shown only when any network device 15 not schedule for the communication Scheduling plot can be seen after running the simulink network model Scheduling plot provides communication time of all the devices with their execution time which gives more clear idea to make scheduling method more efficient and reliable At the same time we can also check the message on Matlab command prompt if there is any packet loss at some devices and communication range for the given transmission power 3 1 9 Write the complete thesis report After designing and implementation of the simulator finished we start writing the thesis report Structure of the thesis report can be seen in section 1 5 3 1 10 Finishing touch Thesis report has been modified and re corrected after the feedback from the supervisor 3 2 Architecture of schematic network diagram Gatewa 3 Sensor Node y Controller 2 Device 4 1 5 v Process Plant Actuator Figure 10 Basic Block Diagram of Wireless Network System Figure 10 shows the basic block diagram for modeling the simulink block for WirelessHART simulator Sensor Node reads the process variable value which needs to be controlled from the process plant and then t
57. oute packets on behalf of other network devices The network layer also provides upstream and downstream redundant path packet routing with high reliability and managed latency from the source to the destination Dynamic bandwidth allocation to field devices based on the communication requirements is the key feature of WirelessHART network Each device in a network can support or more SuperFrame which defines the schedule of individual device to communicate with the other network devices All devices in a network listens for new and disconnected or dropped devices in the network and reports about statistics to their parent network device 1 WirelessHART network layer has defined two kinds of routing Graph The graph routing techniques offer flexible communication path between the source and destination devices Generally device keeps the complete picture of network system and other devices allocation in the network Redundant paths are possible from source to destination Communication path between source and destination is decided on the conditions of network 14 Theoretical background Source The source route offers the static single communication path between each source and destination device Source route 15 defined generally in the packet itself There is a high probability of packet loss with this route if the network traffic is high in the defined route for the packet 7 How the new device joins the network All devices
58. ow in its polynomial form G16 X xx All the receivers perform a CRC operation on received data to detect error If device fails CRC operation source device is informed by the destination device about the error in the received message Communication tables and buffers Figure 6 Shows the relationships of different data link tables All devices maintain data tables to control the communication by each device and collect the statistic of each communication by the devices Received packets are buffered processed and forwarded if needed Each network device maintains three kinds of tables as defined below Graph ID Destination UniquelD Destination nick name Neighbor Link Superframe SAR ng ID TimeSourceFlag lt Link Option lt NumSlots Status u Link Type Active So Number TimeLastCommunicated Channel Offset BackOffCounter RU BackOffExponent Statistics Figure 6 Data Link Table relationships SuperFrame and Link tables there can be more than one SuperFrame in the network defined by the network manager Each device supports more than one SuperFrame At a time max mum one SuperFrame can be active for each device There can be multiple links supported by each SuperFrame to specify the communication with desired device Neighbor table each device maintains a list of devices with which it has direct connection to communica
59. provides long 64 bit and short nick name 16 bit addresses to each devices in the network Long address contains device type 3 byte device ID 2 byte and HCF OUI 0xIBIEO0 DLL uses TDMA bus arbitration technique that provides guaranteed time slots to each device to communicate with desired devices Shared slots are allocated to have the elastic use of available bandwidth between multiple devices to route the packets to the destination with low power consumption and low latency DLL maintains the one or more SuperFrame which is a frame of sequence of time slots Each time slot is 10 ms long which means 15 long SuperFrame has 100 time slots SuperFrame can be of different length e g 15 2s 45 8s 16 s etc At a time only one SuperFrame can be active in a device 1 DLL 1s responsible to provide highly secure reliable and error free communication of data between WirelessHART devices DLL provides service to the upper network layer Logical Link Control In this section we will discuss the different fields of Data link packet data unit DLPDU Figure 2 shows the structure of the DLPDU e A single byte set to 0x41 A 1 byte address specifier The 1 byte Sequence Number The 2 byte Network ID Destination and Source Addresses either of which can be 2 or 8 bytes long A 1 byte DLPDU specifier The DLL payload A 4 byte keyed Message Integrity Code MIC and A 2 byte ITU T CRC16 2 Theoretical background DLL Payload
60. ransmits to the gateway device Gateway device receives the data from the sensor node and then writes this value to 21 Design and Implementation of a simulator the controller to compute the control signal required to perform control operation in the process plant Controller calculates the value of the control signal and writes this value to the gateway device Gateway reads this value from the controller and then transmits to the actuator Actuator receives the control signal value form the gateway device and writes it to the process plant Process plant performs control operation based on received control signal value Then this process repeats over and over Period and priority for the each task can be defined during the initialization of each device Note 1 WirelessHART has suggested maximum of 255 wireless field devices in a network 2 Numbers in Figure 10 indicates sequence of communication link generated between network devices in one complete communication cycle Before we simulate the performance of the network we should be able to provide user inputs to the network through user interface Below figure 11 shows the brief flow chart of user interface which needs to be designed Architecture of the User Interface was carried out after the long discussion After reading the specification documents from the HCF about WirelessHART and DUST user manual we analyze the different user inputs and outputs for our simulator system which can
61. rnal or external events Assign appropriate node number Figure 18 Flow Chart to initialize the Controller Figure 18 and 19 show the flowchart to configure the controller in the network during communication The Controller task is segmented in the three case segments In the first segment controller reads data from the gateway channel depending on dependency input signal array from the user and in the second segment controller calculates the control signal for the received data and writes the control signal back to the gateway channel depending on dependency output signal array from the user 32 Design and Implementation of a simulator Controller Start gt Calculate the Absolute Slot Number urrent Slot is reserved By controller Yes Y Find which control loop has reserved the slot Get the dependency input and dependency output array for the same control loop Read process value from the gateway as per the dependency input array Calculate the control signal form the received Process Value Write the value of control signal to the Gateway as per the dependency output array CAS Figure 19 Flow Chart of Periodic task of Controller Figure 20 and 21 contains the flowchart to co
62. rror for Control Loop 1 5 32 and SF 1 Device not schedule in the network Device not scheduled in the network B Errors 2 Warnings Figure 36 Screen shot of Health Report for Table 4 55 Testing and Results User Interface An ideal kind of scheduling can be seen in Figure 37 for the Table 5 where there is no time slot where more than one device tries to occupy the same time slot Network device and control loop can share the same time slot Gui ee De Figure 37 Screen shot of User Interface for Table 5 Health Report When there is no error or warnings Scheduling Successful message can be seen as in Figure 38 56 Testing and Results Fille Edit View Insert Tools Desktop Window Help Device ID or Time slot ET les Y Scheduling Successful OK Errors Warnings Figure 38 Screen Shot of Health Report for Table 5 Scheduling Plot Scheduling plot in Figure 39 shows the start time and total execution time of each device Execution time of each device is not user defied and it is fixed in this case Task of the gateway actuator to receive data from the sensor gateway device are event driven So the task starts execution after the completion of execution of corresponding transmitting device 57 Testing and Results 4 5 3 5 2 5 0 5 0 0 01 0 02 0 03 0 04 0 05 0 06 0 07 0 08 0 09 0 1 Figure 39 Screen shot of scheduling simulink plot for Table 5
63. s dependency input and or output message should be displayed providing appropriate error information If any sensor and or actuator 15 not connected to any control loop then their ids should be displayed with red colors on appropriate uitable s cell Show health report which gives the status and error information of scheduling of entire network devices Most challenging task with the above algorithm was to write n different colors in uitable s cells The reason behind this 15 that MATLAB Guide does not offer to write with the different colors in uitable s cells However this problem was solved by using HTML code which can be seen in and studied from Gui m file Another challenge was to show error messages if the scheduling of network devices 15 not done properly for a complete communication cycle This has been carried out by checking for the scheduling of dependency inputs and dependency outputs for each communication cycle for each control loop If the scheduling of dependency input and dependency output devices 15 not done for a complete communication cycle for any control loop error messages can be seen on uitable as well as on health report window Figure 30 shows the screen shot of User Interface Each field on User interface can be studied from the User manual document which can be found in attachment 45 Design and Implementation of a simulator File Edit View Insert Tools Desktop Window Help N
64. t l tt att anv nda skalbar enkel palitlig och ger mer flexibilitet f r installation och drift av utrustning processautomation Den WirelessHART protokollet har blivit popul r f r tradl s kommunikation system inom industriell automation v xt system Men detta protokoll fungerar pa TDMA bussen skiljedom teknik Varje n tverksenhet maste planl ggas anv ndaren operat r f r att m jligg ra kommunikation mellan f ltet enheter och en gateway N gra f retag som damm har redan tillverkat enheten h rdvara f r att genomf ra detta tradl st kommunikationssystem f r industriell automation anl ggning Simulator med detta system ar n dv ndigt f r att imitera systemets prestanda pa datorn med hj lp av datorprogrammering att simulera resultatet varje timeslot Syftet med utformningen av denna simulator att anv nda timeslots mer effektivt och erbjuda kollision fri kommunikation mellan n tverksenheter Det kan vara dags att processen att bygga simulatorn 1 b rjan men 1 slutet av kostnaderna och tiden effektiva l sningar Denna rapport beskriver hur simulatorn har utformats f r att systemet 1 olika faser t ex arkitektur design och implementering etc vii Key Words Key Words WirelessHART network SuperFrame Scheduling Time slot Sensor Actuator Gateway Controller Health Report Dust Network Simulator viii Definition Timeslot Network devices SuperFrame Health Report Dependenc
65. te Clear channel assessment channel hopping to avoid interference black listing time synchronized communication and adjustable transmit power 1s supported to maximize the co existence of WirelessHART network devices and other ISM band equipments 1 2 Dedicated bandwidth and time slots are used to high priority and periodic communication tasks while shared bandwidth 1s provided to event driven tasks such as alarm system ad hoc request response maintenance and network health report or diagnostic report Theoretical background e Robust high security by providing authentication to users and new joining device in the network industry approved standard data encryption technique 2 Highly accurate and robust which entails low risk probability Provides cost and time effective implementation for users as there is no more need of complex wired system e Wide variety of device types available by different manufacturers e Specifically designed for process automation industries by considering different industrial aspects So network is fully interoperable with other networks In industry and reliable e User friendly as it supports fully mesh network by providing features like self organizing and self healing 1 Let us discuss the three main features of the WirelessHART one by one 2 1 1 1 Reliability To accommodate with the reliable communication in plant environment against dense infrastructure the movement of large vehi
66. te with it Graph table all the devices maintain complete route information for all devices to forward message successfully from the source device to destination device 2 12 Theoretical background Medium Access Control Medium Access Control MAC is the data communication protocol and it s the sub layer of the data link layer which is defined the WirelessHART network Architecture 8 In WirelessHART sensor actuator networks access of the shared channels between sensors gateway and actuators are controlled by the MAC protocol MAC protocol uses TDMA and CSMA CA bus arbitration technique for the each network device to access the medium for data communication Below we discuss the Bus arbitration technique used by the WirelessHART MAC protocol WirelessHART TDMA Unlike SuperFrame which is suggested by the IEEE standard 802 15 4 WirelessHART has suggested its own style of SuperFrame SuperFrame is nothing but the collection of time slots repeated at constant rate Each slot may have several links associated with it Slot sizes for the all the SuperFrame are fixed and synchronized with each other SuperFrame is repeated continuously after the execution of all the time slots in it Figure 7 shows the structure of data link layer SuperFrame and characteristics of the timeslot T Source now listening Transaction STX ACK D
67. the algorithm to show the scheduling of each device time slot by time slot on the uitable which follows as below 3 4 1 Algorithm to show Statistics of each timeslot for all SuperFrame on User Interface Read number of SuperFrame in the network Read the length of each SuperFrame Find out the maximum length among all SuperFrame Maximum length becomes number of columns and number of SuperFrame becomes number of rows on uitable Read the time slot for each SuperFrame for each Sensor Write the sensor id in uitable cell based on time slot number and SuperFrame to which it belongs to Read the time slot for each SuperFrame for each actuator 44 Design and Implementation of a simulator Write the actuator id In uitable cell based on time slot number and SuperFrame to which it belongs to Show collision message if more than one device tries to use the same time slot disregarding SuperFrame e Read the start time slot and duration for each SuperFrame for each Control loop Write the control loop id in uitable cell based on start time slot number and SuperFrame to which it belongs to Each control loop id should be written with unique color Read the dependency input and dependency output for each control loop Show all the device 14 in same color which are inter related to each other Show Collision message if more than one control loop besides in same time slot disregarding SuperFrame e If any control loop misses it
68. tries WirelessHART is becoming more popular because of its superior capacity and high performance at low over all cost This simulator evaluates the performance of the physical system on each timeslot based on the input arguments on the computer The TrueTime simulator provides the necessary base to develop this simulator The backbone of this system is a schematic diagram of the entire network which includes all the network devices In the network and 15 built using the Matlab simulink and using the TrueTime simulator library Each device the network 15 supported by the Matlab programming which configures the performance of the each node The second important part of the system is a User interface which allows user defining size of the network and necessary input arguments for each device in the network The User interface 15 built in Matlab Guide 1 1 Background Thesis work has been carried out at ABB Thesis work 15 the part of the EU project Service Oriented Cross Layer Infrastructure for Smart Embedded Devices SOCRADES which is a European research and advanced development project Its primary objective is to develop a design execution and management platform for next generation industrial automation systems SOCRADES plans to develop new methodologies technologies and tools for modeling design and implementation and operation of wired or wireless networked system There are 15 companies universities of 6 different countri
69. ueTime Wireless Network Figure 8 TrueTime Library of Simulink Blocks TrueT me Network or TrueTime Wireless Network block simulates message transfer in a confined network When device needs to transfer a message in a network a transfer started signal is send to the appropriate input channel of the network block After the signal being sent actual data can be transferred through the network and transfer finished signal is sent to the output channel of network block when the transfer of message 15 finished Transferred messages are stored in a buffer of a device until acknowledgement or timeout whichever comes first occurs A general message contains information about sender and receiver actual message data length of message and message priority optional Generally long messages are split in to the packets and transferred packet by packet basis through network Message transmission delay is ignored in a confined network as being very small TrueTime wireless network also allows to choose x y and z input to denote the true location of the nodes 6 Figure 8 shows the TrueTime Library of Simulink Blocks The subsequent network parameters are common to all network models Network type determines the MAC protocol to be used There exists three kind of MAC protocol e g 802 11 b g WLAN 802 15 4 Zigbee and WirelessHART Network number the number of the network block Default network number is 1 and networks must be num
70. uitable to show the inter relationships between each network device and control loop Reason behind this is that working with more colors is not appropriate to differentiate different colors easily Another limitation of the simulator is that 1f any device sensor and or actuator belongs to more than one control loop then that particular device will 60 Conclusions and Future Work be written with the same color as the control loop with higher number to which it belongs to 5 2 Future Work Simulator which 15 designed here 15 still in its preliminary stage There 15 lot more that needs to be done Some of them are mentioned here Simulator currently offers single hop communication which should be extended by its functionality to offer multi hop communication Need to find out the way to use all 15 channels in a single time slot to increase the efficiency of the time slot utilization Multi hop communication and many links in a single time slot lead the User Interface to be modified such that it gives error and warning messages in a more efficient and advanced way e There is also need to design an algorithm which calculates the best possible scheduling method automatically based on the current network type After getting the best possible scheduling method simulator should show results on uitable automatically 61 02 6 References 1 2 3 4 2 6 7 5 9 Hart Communication Foundation Wire
71. umber of Super of Super of Sensors Number of Control Loops Number of Actuators Reset sugar rame and Cimon lag To Bach Sansor Select SuperFrame and TimeSlots for each Actuator Sensor Control Loop Duration Time Slot Aur EEEN SuperFrame Start Time Slots f rde ne SuperFrame Time Slots Dependency input Time Slots mesta Set TimeSlot 2 Set Start Time Slot Remove Set TimeSlot 1 Dependency output Remove Set input output Remove Health Report x Remove show TimeSlots in Table Close 1 2 Figure 30 Screen shot of User interface lay out Below Figure 31 descript the health report containing errors and warnings in scheduling the device in network When there 15 no device scheduled in the network message 15 displayed No Device Allocated When there 15 successful scheduling of all devices message Scheduling Successful can be seen Scheduling is considered as successful when there are no errors and warnings Let us see when simulator gives errors and warnings Warnings e When any device not scheduled for any communication in the network Errors e When more than one network device try to communicate in the same time slot e When more than one control loop try to execute in the same time slot Note sensors actuators and gateway are considered as network device
72. ustries are replacing their wired communication system with the WirelessHART based wireless communication system Major reason behind this is that there are already more than 26 million HART devices exist in industries with more than 1000 different devices and 220 different manufactures WirelessHART 15 a backward compatible to its HART devices which reduces the installation cost of new devices and time to implement the wireless system Moreover WirelessHART offers simple reliable and secure communication between the network devices WirelessHART uses TDMA and CSMA CA bus arbitration technique for the communication between the network devices WirelessHART 15 build using std IEEE 802 15 4 It is obvious to schedule the all network devices on TDMA time frame such that there shall not have any collision of messages and also very efficient at the same time For the network operator who schedules the network devices the most challenging task 15 to assign time slots to each device in the network for 2 way collision free communication as there can exist max 255 network devices in a confined network Any lost data can be hazardous in the industries specially treating with the critical data At the same time scheduling should be such that it uses available time slots in most efficient manner to have maximum communication between devices and low power consumption So we need to find the way which suggests the user with the best possible scheduling method betw
73. uture Work ecce eee eee eee ee ee DI Sel CONCLUSIONS AND LIMITATIONS eot ae itle 59 59 3 1 2 Key JPeatures of Sun lator i bs su 59 59 Ope Limitations OF TCSII ION s eR E E un A 60 9 2 AUTRE H 61 6 References 7 Attachments Table of Contents Xl List of Figures List of Figures FIGURE 1 ELEMENTS OF THE TYPICAL WIRELESSHART INSTALLATION 8 FIGURE 2 STRUCTURE OF THE 10 FIGURES ADDRESS SPECIPIER ee 10 FIGURE 4 CONSTRUCTION OF THE 8 BYTE EUI 64 ADDRESS RN 11 FIGURE S DEPDUSSPECIEIER u ae ea less 11 FIGURE 6 DATA LINK TABLE RELATIONSHIPS RN 12 FIGURE 7 DATA LINK LAYER SUPERERAME nn as UU A Go pe 13 FIGURE 8 TRUETIME LIBRARY OF SIMULINK BLOCKS 16 FIGURE 9 RESEARCH PROCESS Nt 19 FIGURE 10 BASIC BLOCK DIAGRAM OF WIRELESS NETWORK SYSTEM 21 FIGURE 11 ARCHITECTURE OF USER INTERFACE Nt 23 FIGURE 12 THE EXECUTION OF USER CODE IS MODELED BY A SEQUENCE OF SEGMENTS EXECUTED IN ORDER BY THE KERNEL pp 25 FIGURE 13 FLOW CHART TO INITIALIZE THE SENSOR 26 FIGURE 14 FLOW CHART OF APERIODIC SENSOR TASK RN 27 FIGURE 15 FLOW CHART TO INITIALIZE THE GATEWAY 0 28
74. who wish to join the network are provided with the network ID and the join key Join key works as a password for the particular network device New devices are provided with the network ID and join key by the network operator which is a manual process Devices then begin listening to the network traffic and adjust its local clock to synchronize with other network devices Once the joining device receives advertise packet from its neighbor joining device sends its network ID and join key to the parent device Parent device sends this information to the network manager for further credential Once the device 15 authenticated by the network manager it 1s provided with two more keys network key and session key After the joining device 15 credited network manager proceeds to integrate the device in to the network by providing it SuperFrame and link for further communication 7 2 1 4 Application Layer WirelessHART uses command based standard data types and procedures This layer provides standard device specific status for all process variables Deals with Smart publishing of process data periodically and provides smart alarm system on crossing user defined threshold 1 2 2 Introduction to TrueTime Simulator TrueTime 1s a Matlab Simulink based simulator for real time control systems which facilitates co simulation of controller task execution network transmission and continuous plant dynamics This is accomplished by models of real ti
75. y input Dependency output Link Definition Fixed small portion of time of SuperFrame Sensors actuators and gateway are called here as network devices Set of series of timeslot which keeps the link information for each timeslot Contains the status of current scheduling method containing error warning messages if any Each control loop depends on inputs from certain sensors These sensors area called dependency input for the belonged control loop Calculated control signal by each control loop has to be sent to certain actuators These actuators are called dependency output for the belonged control loop The full communication specification between adjacent nodes in the network 1 the communication parameters necessary to move packet one hop 1X Table of Contents Table of Contents 52 2 V I LU IBACKGROUNDE ee ER Ne aruis 1 1 2 PURPOSE AND uo n xad edd 2 1 3 TDEEIMITS ee A 3 INNER 4 2 Theoretical Background cce ee ee ecce eee eene eene eee D 24 WIREEESSEDSR I NETWORK oido e een 5 DN CN CCL UU See c ee 5 6 Z2 4 2 1 1 3 TU 7
76. zi D O0 74 C Ch 4 CO ND o 2 0 7 OO SON gt Set Start Time Slot Set TimeSlot emove AT P Dependency output 42 Remove A4 AS Set input output Health Report show TimeSlots in Table Close Time Slot_1 Time Slot_2 Time Slot_3 Time Slot 4 Time Slot 5 Time Slot 6 52 CL1 S3 CL2 S4 CL3 S5 CL4 CL5 Time Slot 7 Time Slot 8 Time Slot 9 Time Slot 10 Time Slot 11 Time Slot 12 Time Slot 13 A2 A3 A4 5 52 CL1 S3 CL2 5 SuperFrame 1 SuperFrame 2 SuperFrame 3 Dependency input Error in input Error in input Dependency output Error in output Error in output gni gt Figure 35 Screen Shot of User interface for 4 Health Report Detailed error description can be seen in the Figure 36 for the scheduling of devices suggested as in Table 4 Each error types are displayed with different colors which help to debug errors easily 215154 Y File Edit View Insert Tools Desktop Window Help a Device ID or Time slot Dependency input error for Control Loop 1 TS 12 and SF 1 Dependency Output error for Control Loop 1 T5 2 and SF 1 Dependency input error for Control Loop 1 TS 22 and SF 1 OK Dependency Output error for Control Loop 1 TS 12 and SF 1 Dependency input error for Control Loop 1 TS 32 and SF 1 Dependency Output error for Control Loop 4 TS 22 and SF 1 Dependency input error for Control Loop 1 TS and SF 1 Dependency Output e

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