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designing and programming automation in distributed

1. I APPLICATION Primary 06107 Ra acne Secondary F6111 I i 4 2 S 2 S 5 SETPOINT 12 30 pH Flow meas feedback N A I I GRAPH 16 Q6107 and F6111 cascade control Also in this case calculating the transfer function can be helpful in order to estimate control behavior To ease the calculation the secondary controller transfer function 1s first resolved The secondary transfer function is then placed in the main equation where G2 s is the secondary function and is the control valve dynamics In order to narrow down the equation the controller terms P I and D are abbreviated in a single block PID First the transfer function for the secondary PID controller is resolved in 4 3 and 4 4 Here there is no G term due to the fact that there is no actuator directly controlled by this control loop n SpPID PvPID 4 3 Pv 1 PID SpPID Pv PID 4 4 ti sp 137 26 After the secondary controller transfer function Go s is resolved it can be inserted in to the main equation for the primary controller loop Here also the valve dynamics Gy is taken into account SpPID gt G s G 5 4 5 Pv 1 5 SpPID G s G 30 Finally by expanding the final equation it results as the transfer function for the whole cascade control event G s PID Pv PI
2. H 1482002 LISATTY Q7311 G 17 4 2002 LISATTY P7313 F 1142002 LIS TTY F7313 JA POISTETTU F 7314 E 30 10 2001 LISATTY F7318 D 14 6 2001 POISTETTU F7313 OSASTO 21 LIUOTTO 3172000 LIS TTY POSITIO TUNNUKSIA B 9421999 INV M7319 SAATO MUUTETTU F7317 F7315 KOHDE S02 SAILIO 21 10 1999 PI KAAVIO Nro Pym us CCCs Nini I0N341 TION341 APPENDIX 3 4 sAsiuuAeyewyA unsed SZH m HOEN APPENDIX 4 950 eeayne as uays nsijeeuuou uo nnjnedeA 705 gua eueleea uo ef 2 OL 1 eesnou AIN sof ueejajsuny SD APPENDIX 5 Suid EEMNREENSMMENEEEEEEENEEEEENEEEEEENENZ HY 4 4 Xv MeL FABY OLJIE wv TE oiron DWANPR orl une anf D TLbODE OASIS ed SIE SIWSUO 90 20 958 M FD S1DE SALIAMd EQV 9 4 N E al 7 77 sassnd L g 1 21 a T N NILIIT H EEG 1 1 LI d lt ao HISHH IP t HIIN33 LL NE T T L LII T LB eS e
3. PES2 POS pipeline 1 temperature PES2 H2S pipeline 2 temperature 1 PES2 area temperature j A T E dE A a 1 O m 1 SEES T6111 T6112 pg 50 50 T6113 T6114 F6ll NaOH gt PES2 H6132 H2S pressure release valve H6133 Emergency shower PES2 area L6112 fIPES2vel P6109 21PES2 gas vacuum pressure control P6110 21PES2 pressure differenee 06106 PES2 area H2S alarm 06107 PES2pH 0 00 06108 PES2cycepH 06110 PES2 H2S measurement T6lll PES2tempemtue T6112 PES2H2S pipeline 1 temperature T6113 PES2H2S pipeline 2 temperature 5 614 PES2area temperature 2 4 1 2 Control loops and control theory Control loops are used to automatically regulate or direct a device to a desired setpoint They are applied when a process guantity is sensitive to deviation due to changing environmental conditions or anomalies In practice the operator sets the desired setpoint in the control loop faceplate see Graph 8 on page 15 and selects the desired control method automatic manual or external control As expressed in section 4 1 a PID controller must be used with the pump M6138 The pressure in the pipeline must be kept at 6 0 mbar for efficient gas removal The pressure might deviate due to different factors such as dirt in the pipeline
4. ExtRefautol P7312 Arvo In the code the variables P7306 Arvo and P7312 Arvo are used to store the setpoint values of the respective PID controllers The first statement switches the control mode to external control in order for the values to be set as setpoints The following else statement returns the values to normal and does no longer force external control once the button is turned off The last lines of code explains that the external reference values are the variables P7306 Arvo and P7312 Arvo 5 3 Summary This chapter covered the automation case of the SO distribution tank It discussed operational principle of the system and the programming related to it The paragraph also gave more insight to how Structured Text applications are designed and finally programmed In section 5 2 3 it becomes apparent how Function Blocks can be utilized in ST code in addition to traditional C language like conditional statements 51 6 CONCLUSIONS In this thesis distributed control systems were studied and the automation programming of two process devices performed The IEC 61131 3 programming languages were used for the programming of these devices in the ABB System 800xA DCS The two devices H2S desulphurization system and SO distribution tank were designed and programmed with user friendliness safety and operability as main priorities The first part of the programming work was to create a new application in the Control Buil
5. I P7306 E i PV 7306 6 3 bar x rn X or 3 5 bar N D P7306 MIT e a 4 4 LL FEEDBACK MEASURED VALUE GRAPH 26 SO distribution tank control loops 5 2 Practical programming phases The program for the SO was done under the application App 2 created previously see Section 4 2 A new sub application labeled SO2 S ili was created for the control modules and code specific to the SO tank The first step was to look over all the circuit diagrams for the devices to be programmed see Appendix 5 The control modules were then created and parameterized in the same way as in Graph 19 Some conflicts between the circuit diagrams and the actual old programs were found For example there were devices documented that had not been in use for a long time These were presumably caused by a lack of communication as the process had been changed over the years However these conflicts were quickly resolved Once the control modules had been programmed the hardware definitions were added This was done also in the same way as in Section 4 2 The I O connection setups were received from the documentation designers and then added to the hardware structure in the Control Builder All the instruments from Table 3 on page 42 were now defined to the DCS 5 2 1 Process graphics display The creation of the Human Machi
6. Profibus DP PID controller Distributed Control System automation system commonly used in process automation Input Output describes external signal connections Human Machine Interface a terminal used to interact with devices Communication Interface used to connect external devices to target Protocol Internet Protocol Transmission Control communication protocol used in the internet and other networks Foundation Fieldbus a fieldbus standard Domain Name System naming system for resources connected to the internet or other private network Object Linking and Embedding for Process Control communication standard for automation systems and devices Central Processing Unit hardware within a device that carries out instructions of a computer program Process Field Bus Decentralized Peripherals used to operate sensors and actuators in automation systems Proportional Integral Derivative controller used to automatically direct a quantity to a desired setpoint A D converter RNRP MCC FBD ST SFC IEC 61131 3 ATEX RTDB Analog to Digital converter converts a continuous physical quantity to a digital number Redundant Network Routing Protocol used to switch to a secondary network in a duplicated system Motor Control Center an assembly of several motor control units which can contain a set of auxiliary devices Function Block Diagram a graphical programming language used c
7. STIS s ILMA Sas TL EL000 91 180 us gt 0 BEZO0E lt e e l a x U L EL000E amp mo TEE E 0 x Ln T m lt d a 2 n i E an A u lac a b LAPUS CoNS VALSS 17 SISTA _ 5 4 vo E e APPENDIX 1 6 4 A 0 500 ppm N ytemuhvi R2 p gt Luokka 2 Sis lt putkistot ja kanavat Huone sis puolelta kokonaisuudessaan al TI G 21 ILA 100 7 7 vid L MMITYSILMA KOPIN L MP TILA 4 v656 6106 gt lt 21PES2 DISSE 21 122 ENA 50 10550 T 6110 3 2 Pdl PT 5110 TA 6110 ea KAA 1 FT al pH m 1 1000 617 a 4 ay 4 T F 6111 M messa 6107 ED 2 lt N 21 122 ENA 25 10H4 0 v631 25 V641 25 220 g l 21PUH18 5 BOs 4 Laim NaOH 6111 6111 M6139 z E 1800 A a 21 124 ENA 50 10550 V 21P216 A 7 K gt gt POISTOILMA V amp 78 25 V677 25 21 11 KTY 25 10H40 3 TYPPI 2 JA C POHJOINEN VIEM RI D 3122012 LIS TTY EJEKTORI 06110 H2S MITTAUKSELLE 24 LIUOTTO C 1892012 52 LIPEANSAADON MUUTOS WEM
8. Also alarms are triggered by the measurements programmer set high limit or low limit values The alarms alert operators of abnormal conditions so that appropriate actions can be performed 26 GRAPH 14 Indoor view of the desulphurization system 4 1 1 Instrumentation Instruments are all the devices connected to the DCS excluding electric motors Table 2 is a list of all the instruments used in the desulphurization system The table shows I O connections of each instrument both analog and digital tags descriptions and measurement properties Columns labeled with ex are connections to and from ATEX certified I O modules Also the instruments themselves must be ATEX certified due to the explosive nature of hydrogen sulphide TABLE 2 Instrument list of the H2S desulphurization system Tag Description JAI ex AO ex DOex Range Unit F6109 Waer2PE2 aif f 41406 Jj Foo PES2cycle 1 0 5 jm NaOH gt PES2 0 20 m H6132 H2S pressure release valve 2 jon off H6133 on off L6112 P6109 P6110 6106 6107 6108 6110 C C 1 Emergency shower PES2 area 2 PES2 level S j A 2 PES2 gas vacuum pressure control m m 2 PES2 pressure difference m EN mA A PES2 area H2S alarm PES2 pH PES2 cycle pH PES2 H2S measurement PES2 temperature
9. Hydrogen sulfide is an explosive heavier than air poisonous and corrosive gas At Freeport Cobalt Ltd the gas is used in precipitation of metals in various stages of solution purification The residue gas is collected from different stages and directed by the means of vacuum suction to the desulphurization system from here on referred to as the scrubber In the scrubber the toxic is sprayed with a mixture of water and sodium hydroxide to absorb the sulfur to that purification solution The purified gas is then released via the chimney in which the scrubber is located to the open air The operation of the scrubber is visualized in Graph 13 Paloranta 2013 The treatment of the gas is very important due to its high toxicity Upon inhalation hydrogen sulfide reacts with enzymes in the bloodstream and inhibits cellular respiration resulting in pulmonary paralysis sudden collapse and death Continuous exposure to low 15 50 ppm concentrations will generally cause irritation to mucous membranes and may also cause headaches dizziness and nausea Higher concentrations 200 300 ppm may result in respiratory arrest leading to coma and unconsciousness Exposures for more than 30 minutes at concentrations greater than 700 ppm have been fatal M Syed G Soreanu P Falletta and M B land 2006 Purge GRAPH 13 A bioscrubber system for removal of H2S Syed M Soreanu G Falletta P and B land M 2006 25 4 1 Operation
10. Liquid 502 transfer nitrogen pressure 1 i EET 2 Ai A O Differential pressure liquid SO2 tank 1 1 1 E KU2 gas space pressure E Em O ldo O O O O Liquid SO2 tank nitrogen pressure LL J SO2 transfer nitrogen pressure 2 1 O NO Liquid SO2 tank area gas alarm 1 1 aa C q Liquid SO2 tank area gas alarm 2 r a Liquid SO2tank areagasalam3 1 Liquid SO2tank areagasalam4 1 EE _ i O O O O R ID lt C1 OI Liquid 502 line temperature ii 7303 Liquid 502 tank temperature 1 I i J E 3 _ E p 5 1 2 Control loops There are two control loops P7312 and P7306 utilized in control of the hydrogen pressure Pressure is measured with sensors attached to the pipelines The sensors give a feedback signal to the PID controllers which then control valves that constrict or open the flow accordingly Graph 26 shows the logical structure of the PID controller P7306 The controller tagged P7312 is very similar to this The setpoints of both controllers have two main values this is for the purpose of creating a pressure difference when the tank is being refilled with SO gt More of this in Section 5 2 3 T ee APPLICATION PID CONTROLLER
11. gold and molybdenum FCX is the world s largest publicly traded copper producer and has a dynamic portfolio of operating expansion and growth projects in the copper industry FCX is also the world s largest producer of molybdenum and a significant gold producer The company s global workforce includes approximately 34 000 employees Freeport McMoran Copper amp Gold Inc 2013 Freeport Cobalt Ltd previously OMG Kokkola Chemical Ltd is a chemical plant located in Kokkola Finland and is a new acquisition by FCX With around 400 employees the plant produces inorganic salts oxides and various types of cobalt powders from cobalt and nickel additionally metallic carboxylates and copper cathode plates As raw materials the plant uses enriched cobalt cobalt containing intermediate products and metal granule that is imported from Africa and is refined on site The final products are used in a variety of applications such as in the battery industry petrochemicals industry in tungsten carbide blades and many other OMG Kokkola Chemicals Ltd 2011 The plant process flow is presented in Graph The process starts with dissolution where cobalt is separated from other metals contained in the raw material Copper contained in the raw material is separated from the cobalt by electrolysis which will result in pure copper cathodes Other valuable metals such as germanium and nickel are also separated and sold The cobalt is cleansed in
12. the result is added to the minimum range value of the secondary controller to get the actual setpoint value 120 8 128 The formula for the scaling resulted as the following below Outp Setp Pmax Pmin ry Pmin 4 7 where Setp setpoint value to the secondary controller Pmax maximum parametrized range value of the secondary controller Pmin minimum parametrized range value of the secondary controller Outp Output value of the primary controller as percentage 38 4 2 4 System sequence start and stop The system sequence start and stop function starts or stops the system motors and controllers in a set order with a single click from the operator screen The function helps to ensure devices are started or stopped in the correct order so as to prevent safety hazards device breakdowns or environmental issues The sequence was made with the built in group function defined in the standard library of the ABB 800xA DCS The start and stop order is defined in the device specific control modules see Graph 19 on page 32 In the control module there are five parameters used to define the device Operation in a group sequence First there was defined to which group the device belongs to A new data type GrpDrvCon was created under the desulphurization system data types After this by defining the device control module with the parameter 25 Kaasupesuri GrpDrvCon assigned the device to that group Next the s
13. Access Variables H i 5 d AC21 Classified information Updating Search data for controller AC21 1 0 0 Update of Search data finished Opening project finished ABBAdmin GRAPH 10 Liuotto project in Control Builder 3 2 5 Graphics Builder Graphics Builder is a tool that enables configuration of graphic aspects Graphic aspects are graphic displays graphic elements and faceplates The configuration of graphic displays is easy and intuitive hence this does not require lot of programming skill At Freeport Cobalt the displays are usually made to correspond with the P amp I diagrams Tanks and flow lines are made into static objects whereas the devices are presented in dynamic objects which can be interacted with ABB Inc 2012c 19 There are several features included in the Graphics Builder Expression Builder which allows assigning of expressions which is to specify the relationship between the process data and the data that will be displayed to the operator Element Browser contains ready made objects from where the user can select appropriate graphic elements for inclusion Design and test function permits building of graphic aspects in design mode and then to check their behavior in test mode Finally a Solution Library where user defined graphic solutions can be stored for reuse ABB Inc 2012c 3 3 Programming languages In this section three IEC 61131 3 programming languages u
14. Because of this the suction force must be constantly adjusted This is achieved by the PID controller that sets the revolution speed for the pump As shown in Graph 15 a pressure sensor is installed to the main transfer line tagged P6109_MIT that gives feedback to the PID controller tagged P6109 creating a closed control loop If there is deviation between the setpoint and feedback measured value the controller will compensate for it SETPOINT O Q 6 mbar BS FEEDBACK MEASURED VALUE GRAPH 15 P6109 closed control loop Inside the PID controller three tuning parameters exist The proportional gain term sets a constant output value in relation to the deviation between the MV and SP The Integral eain accelerates the output value if the feedback does not change towards the desired SP fast enough The derivative term examines the rate of change from a deviated value towards the SP and tries to compensate for deviation before it occurs 28 Tuning the parameters can be done either manually trying different parameters trial and error or by mathematically calculating the behavior of the system By introducing a term G that stands for the pump s dynamics in front of the P term in Graph 15 the response of the control event can be estimated with the help of the transfer function G s In the formula 4 1 Pv stands for Process Value and Sp for Setpoint Pv Sp I D PG PvPG I D as Pv 1 PG I D Sp I D
15. JE E gt 1 LIT ET N 127 Pos I OIILINJANNONS 31853N 205 HI II MHidSH 205 IIIILIMd SIILSHWHTII NMBHHdSH c05 E HIIN3M z n DHABEZ 4 F IJTIILLM3SATTAMBE SHE 2NH SHSI FEES d D JE 1 Ulla N 2 9 o TE SAL SAAN gt I L SE JE 822 EI RI k OT3 L0 33 oj lt p gt s 1122 J 1 1 Cn r I esu Ig JI I z M cs 1 p gt gt d lt D 2 1220 0 fy i n3 3n1g ose B NAZIOA QT3103 33 lz Fa E J m LHR dl BAL T E i rag EUBE P E L 4 4 x T Hie z mu ss mmm Tb 3 eer AB 5550 x NE D 1 I L lt gt X O 131021 AINE N nan BILLING OWOATHA n nn mS m 1 h v n 71 i e H d LLLA 07131034 3 sija 3018510 z 282 TETA EHH ABE H Lo E pL pP S 1 lt 1 Ta 1 MAL wo z 3079H E 1 205 HLINJN sija 7 PE eee ee ie HHH HHHH APPENDIX 11 TIWH ZTELO 1IIW ETEL IIW ZIELO aesyAQATREUNSeeY ZOS TVH ZIELO L p 00800 a WIG TWilIW ZTELO LE p LS 0081V d WITH TV
16. _H6132 M6138 EnableMode True eo M6139 Enablestatus True amp pip P6109 n omen e EnableTagNa True 00 4 m ee EnableUnit True eo Preview EnableValue1 True eo MOT1MCandUnit Displays the actual motor current EnableValue2 True eo K Run EnableValue3 True EnableValue4 True eo MOT1StaTxt o Height 48 Displays object status information for a 9 one direction motor as text Name PIDCtri PIDCtri1 NumberOfDigits 4 9 Rotation 0 MOT1Symbol T Displays object status information for a SubscriptionR 0 one direction motor Transform Empty UnitSize 8 Valuetindicati 0 RunTimeCnt Displays object run time S ToolBoxes Element Explorer 4 wa teady Aspect approved Online Mode 8 KOK ABB ABBAdmin 08988 GRAPH 22 Configuration of H2S desuplhurization system graphics After placing the objects their representation to the operator was also defined For example the system does not distinguish motor types before their representation is defined in the graphics In this case the motors were pumps so their symbols were changed to pump symbols instead of conventional motors Also definitions for alarm representation were made for the emergency shower activation A bar was also added for the group 35 sequence start of the system explained further in paragraph 4 2 4 Documents were also created to explain the function of interlocks and the group s
17. abs w7302_Naytel w7302 Nayte2 AIC W7302 KULUTUS Signal IOValue w7302 Uusi 360 0 As seen from the final line of the code the variable the final value 1s written to 1s of AIC data type Analog Input Calculated This is a separate Control Module that the system treats as if it were of normal AIS data type The only difference is that the AIC signal comes from the code rather than an actual field instrument The AIC measurement was also then imported into the process graphics The final product can in theory be used for calculating the consumption of any tank or container with a level or weight measurement and constant consumption Only thing needed to incorporate the code in to another application is to change the variables 5 2 4 Automatic control loop setpoint drop As described in section 5 1 the transfer of sulfur dioxide is done by applying constant nitrogen pressure in to the SO tank In tank filling situations the same pressure is applied to the tanker truck SO The pressure will initially be the same in both tanks and thus SO does not move In order to move the SO a pressure difference must be created between the truck and the SO storage tank The elements controlling the pressure in the 49 SO tank are the control loops P7306 and P7312 The setpoint of these controllers must be dropped by 3bar for the refilling operation to be possible In a refilling operation the operators were instructed to pu
18. and run from the aspect servers as explained in section 3 1 2 ABB Inc 2012b 17 N ineerin OMG Kokkola Engineering Workp 2 xi 3 p Enter search name Fiter M Replace v ti i n Sie E Control Structure Aspects of App 2 Modified Mod fed by Descrioton Inhented Category name Version Reserved by Reserve comment Alarm List 7 12 2007 20 27 27 Minerals Library This aspect category is used to True Alarm and Event List 1 KOK ABS ABBA appication 4 18 2013 13 30 12 KOK ABBWBSA Control aspect for an application Fase Application 1 KOK ABB ABBA Aspect Category Definiton 2 25 2013 12 59 46 KOK ABBIABSA The base Aspect Category categ Fase Aspect Category Definition 1 KOK ABB ABBA Control Alarm Event 2 12 59 45 Aspect that shows the used alar F Control Alarm Event 1 KOK ABB ABBA Control Application Type Reference 2 2 KOK ABB ABBA Control Application 1 KOK ABB ABBA wv Control Builder Name 2 KOK ABB ABBA bject type False Control Buiider Name 1 contra Properties KOK ABB ABBA Control Properties 1 KOK ABB AEBA Vy Control Structure KOK ASB ABBA False Control Structure 1 KOK ABB ABBA V Control Structure KOK ABB ABBA Fas Control Structure 1 KOK ABB ABBA Event Ust fi 7 20 35 Minerals Library d to c True Alarm and Event List 1 KOK ABB ABBA 43 GroupUploader 1
19. any given period of time As discussed in the introduction of Section 5 the total consumption varies depending on the raw materials to be dissolved in the plant This would also help to estimate the need for refills The boiling point for sulfur dioxide is 10 C and the melting point 72 C Because the temperature in Finland might vary between 30 C in the winter and 30 C in the summer the matter state of the sulfur dioxide is in liguid form in the winter and gas in the summer From the automation point of view this makes it hard to measure the flow of sulfur dioxide Therefore no flow measurement was installed that could be used to show consumption The total consumption of the sulfur dioxide had to be measured with the decreasing weight of the tank over time It was stated that the weight measurement of the tank was accurate and reliable and could thus be used to estimate the consumption The programming principle was to take samples of the weight at fixed time intervals Once two samples would be taken the absolute differential result of these two values would show the consumption in the set time frame Finally by multiplying the time by a necessary amount would give the consumption in kilograms per hour This principle is illustrated in Graph 21 46 wee Sampler 1 delay 2t 4 x Sampler 2 delay 2t sample 1 x sample 2 C4 1 PAH Aas sample 3 92 1
20. are utilized for American and Asian markets The plant has a central warehouse from where most of the products are delivered to customers in Europe The other main market areas have their respective intermediate warehouses OMG Kokkola Chemicals Ltd 2011 3 DISTRIBUTED CONTROL SYSTEM Distributed Control System or DCS is a broad term used by many decentralized electrical systems In this case DCS is referred to the industrial process automation system The applied automation system at Freeport Cobalt Ltd utilizes distributed control architecture A distributed control system consists of several processor units called controllers geographically spread throughout the plant Each controller has its own sub system that is independent of the other controllers The DCS architecture is characterized by these conventional I O input output subsystems in which racks of I O modules are networked to their respective centralized controller via an I O subsystem network Controllers are connected to system connectivity servers which are read by operator computer terminals for information and interaction of the plant processes Berge J 2002 Controllers are usually divided by plant sections for example one for refining process and another for chemicals production The physical process instruments and motors are connected to I O modules by either current loops of 4 20mA or digital pulses The I O modules are arranged in clusters which are then connec
21. computers which compute I O data and run programs designed to control plant functions PID control functions for example are calculated in the CPU The clock frequency is usually between 24MHz to 500MHz Because the execution is not continuous the downloaded program is run through in fixed intervals for example 500 1000ms Communication modules are fieldbus master CI s which connect remote slave devices to the CPU Support for different fieldbus standards varies by manufacturer In Graph 5 is an example controller rack with from the right a PSU an empty I O connection plate 16 bit digital input module CPU with Ethernet CI s and a Profibus DP CI Paloranta 2013 11 Vue at nmD o u l i 1 1T1 m nM GRAPH 5 Simple controller rack setup 3 1 4 I O signals and module types Input Output modules have the task to send and receive signals from the physical process devices There are four basic types of I O Digital Input Output modules and Analog Input Output modules As shown in Graph 3 there are alternative methods to receive information from the field devices At Freeport Cobalt mostly traditional I O signals are used and their number is around 30 000 Digital signals are SVDC electric pulses of varying duration The signal is interpreted as a logic level signal with two states 1 and 0 There are no intermediate values and therefore tolerance for rising a
22. connected to the Engineering Workplace control structure Here the previously created control modules can be seen and picked into the graphics as dynamic elements The elements are then placed in the graphics in the spot corresponding to their actual placement In Graph 22 the dynamic objects can be seen as light brown boxes These objects can be later interacted with by the operators Static objects which cannot be interacted with are the pipelines and the scrubber tower Process Graphics Editor Imeytys 21 File Edit View Format Tools Window Help E faa am mn un Id HL EL i 0 QUA G K 19 OL E POS Sai yli E E DG OG EXxSw podgueA lement Explorer SERI Items w D 8 GROUP GroupD11 1 Show all structures amp Group g Api hg MOT1 MOT11 MOT1 a go MOT1 MOT12 MOT1 Control Modules 8 PIDCtri PIDCtri1 8 a AIC DING DING HD l d m AIS Properties IEC Poisto 8 Aoc l 9 E os Customize False eO Strippaus Saostus Element _P6109 PIDCtrl e 2 m REESBEBREHEEENEI EnableDescri True 805 Doc EnableFitToB True eo pos a H2S_Kaasupesur Enablelnput True 90 123 21PES2 EnableLimitL True pa
23. in case no AOX is used 10 ActuatorPos ReallO 10 H2S_Kaasupesuri Q6107 Out OUTP unspecified IN OUT Actuator Position Use O lt GRP gt lt PID gt Out OUTP in case no Actuator position is available 11 ShowActPos bool true false unspecified bool If true the actuator position is presented in the faceplate 12 BalRef real 0 0 unspecified IN BALancing REFerence input Safety value assigned to the OUTPut in case I O or HW error occurs 13 GrpStep1 dint cBMI DINT 0 1 unspecified IN Group Step 1 to to activate GrpMode1 during starting 1 999 during stopping 1001 1999 0 not used 14 GrpMode1 dint 2 5 unspecified IN Mode selection for GrpStep1 1 Man 2 Auto 3 ExtMan1 4 ExtMan2 5 ExtAuto1 6 ExtAuto2 15 GrpStep1Delay time cBMI Time0s unspecified IN Activation Deactivation delay for Group Step 1 16 GrpPreSelection1 string 50 cBMI Empty str unspecified IN PreBins the consumer is assigned to Syntax P1 amp P2 P3 amp N4 P1 AND P2 OR AND NOT P4 AND before OR N 17 GrpStep2 dint cBMI DINT 0 1001 unspecified IN Group Step 2 to to activate GrpMode2 during starting 1 999 during stopping 1001 1999 0 not us 18 GrpMode2 dint 3 unspecified IN Mode selection for GrpStep2 1 Man 2 Auto 3 ExtMan1 4 ExtMan2 5 ExtAuto1 6 ExtAuto2 19 GrpStep2Delay time 05 unspecified IN Activation Deactivation delay for Group Step 2 20 GrpPreSelection2 string 50 cBMI Empty str unspecified PreBins the consumer
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25. lai sample 4 0081 as MENOS ty t2 t3 t4 GRAPH 27 Principle of code used to calculate consumption of SO The process of designing the code was by trial and error of several different methods and Function Blocks After several alternatives were developed the most simple and elegant solution was selected This solution was to introduce two Pulse Timer Function Blocks two Real Shift Register Function Blocks and a Timer On Function Block The idea was that the signal from the weight measurement W7302_MIT would constantly be fed to the inputs of the two shift registers In Graph 28 is a ShiftRegister Function Block If the Load parameter is True or if the Write parameter goes from False to True the In n extensible inputs are copied to the Out n extensible outputs GRAPH 28 ShiftRegisterReal Function Block The boolean signals to the Write parameter of the registers was fed in pulses of fixed time intervals by the two Pulse Timer Blocks Graph 29 Finally the output of the shift 47 registers was differentiated and the absolute value of the result multiplied by 360 to get consumption value in kilograms per hour GRAPH 29 Timing diagram of PulseGenerator Function Block As seen in Graph 27 the pulse signals do not overlap because if they would this would not show any deviation in the weight To prevent the overlapping of the two sample intervals a delay of one time
26. programming was started by adding a new application labeled App_2 in the Control builder see section 3 2 4 Graph 10 The next step was to connect the standard libraries to the application about libraries see sections 3 2 and 3 3 1 The libraries contain inter alia definitions for different data types which were added next In the data type folders instrument and device tags were added so that the program would know what kind of device each tag was For example a temperature sensor has a single current loop connection that sends information to the DCS therefore it is of AI Analog Input data type Once all the devices Table 2 on page 26 and motors were added with their respective data types and tags it was time to parameter them All the parameter definitions for a device contained in a control module Common parameters for each control module were tag names and descriptions connection to the respective data variable and alarm class Rest of the parameters varied by data type for example a PID controller control module contained 126 parameter definitions These 22 parameters define alarm limits tuning parameters enabling of various control modes and more All of the parameters were not used and the system had predefined default values for those left empty In Graph 19 are some of the parameters of the PID Q6107 On row 9 is the output connection of the PID In case of the PID P6109 there was written the connection to the pum
27. statements if then else iteration statements for while repeat and control statements exit return ABB Inc 2012e 22 The following example shows when Function Blocks as the one in Graph 11 are called by a statement consisting of the function block name followed by a list of named input and output parameter value assignments The output is written in to a variable for use in other parts of the application PulseTimerl PulseTime Timels Enable lt true PeriodTime Time20s cc WISUA Value js 3 3 3 Sequential Function Chart The Sequential Function Chart SFC programming language allows the user to describe the sequential behavior of the control program graphically The language was studied mainly to interpret sequences previously made in the plant SFC concept enables all control actions for a process to be described in one compound sequence structure Sequences can be hierarchical that 1s action chains can be grouped to give a clear high level presentation of the process control unit ABB Inc 2012e Graphically SFC is visualized in the editor in a series of steps represented by rectangular boxes and connected by vertical lines Each step represents a physical state of the system being controlled On each connecting line there is a horizontal bar representing a transition The transition is associated with a transition condition which when true deactivates the step before the transition and act
28. the solvent extraction process where impurities are removed before the end product preparation End products cobalt chemicals and powders are manufactured from the pure cobalt solution Cobalt powder is manufactured by reducing the cobalt into metal powder with the use of hydrogen gas Metal carboxylate products are also included in the end products OMG Kokkola Chemicals Ltd 2011 Cleansing of solution Dissolution of raw materials Copper extraction Cobalt Cobalt Iron removal extraction products Preparation Germanium N Metal of Copper oxide i carboxylate cathodes preparation GRAPH 1 Process chart of Freeport Cobalt Ltd OMG Kokkola Chemicals Ltd 2011 The development of products and manufacturing methods and a fully automated continuous process is an essential part of maintaining company competitiveness in the global market Freeport Cobalt invests a great deal in these aspects and aims to develop products to match customer needs Freeport Cobalt Ltd produces analysis and testing services for the needs of production quality control research and development Advanced modern methods are used in the laboratory for the examination and metal analysis for studying the physical properties of the products OMG Kokkola Chemicals Ltd 2011 Freeport Cobalt Ltd Supplies products worldwide to over 50 countries Most of the logistics and transport is done by trucks but also shipping and rail transports
29. 012 21 Up down counter bot QU IL l GRAPH 11 Example of a CTUD counter block ABB Inc 2012e The downside of FBD is its weak support for conditional statements when one or more actions should be reiterated for a specific number of times or only as long as a certain condition is fulfilled This kind of construct is much easier to accomplish in the ST language with statements such as FOR WHILE or IF ABB Inc 2012e 3 3 2 Structured Text Structured Text ST is a high level programming language similar to Pascal and C that has been specifically designed for use in programmable controllers It is compact highly structured and contains a comprehensive range of constructs for assignments function function block calls expressions conditional statement iterations and more This language was used to code the majority of the practical work The code is simple to write and easy to read because of its logical and structured layout ABB Inc 2012e On the whole ST is very effective tool for developing control applications The language is a good general purpose tool for expressing different types of behavior with all kinds of structured variables This should be the choice of language when iterations are needed that is when something is to be repeated a fixed or conditional number of times The ST language contains a list of statements such as assignment statements like variable expression conditional
30. 13 National Instruments Corp 2012 Fundamentals System Design and Setup for the 4 to 20 MA Current Loop Available http www ni com white paper 6940 en Accessed 13 March 2013 NITK Surathkal 2011 Distributed Control System Available http solve nitk ac in dmdocuments electrical DCS write up pdf Accessed 5 March 2013 OMG Kokkola Chemicals Oy 2011 Kest v kemiaa Available http www kip fi omg digipaper index html Accessed 2 January 2013 OPC Foundation 2013 OPC description Available http www opcfoundation org Default aspx 01 about 01 whatis asp MID AboutOPC Accessed 11 March 2013 56 Paloranta M 2012 Automaatioj rjestelm EN short ppt Presentation of automation system Freeport Cobalt Ltd Paloranta M 2013 Interviews with Paloranta Matias process system engineer at Freeport Cobalt Ltd between 1 March to 1 June 2013 PI organization 2013 PROFIBUS Technology and Application System Description Available http www profibus com nc downloads downloads profibus technology and application system description display Accessed 7 March 2013 Siren J 2013 502 auton purkuohje Work instruction manual University of Alberta 2003 Computer Organization and Architecture II Available http webdocs cs ualberta ca amaral courses 329 webslides Topic2 DeMorganLaws sld017 htm Accessed 14 March 2013 VESI Ei ans TALOU L LOOOGE
31. 223 51 45 MineralsLbrary Graphic Ele tawa True Graphic Bement 1 Alarm List 2 20 Minerals Library i d to c True Alarm and Event List 1 KOK ABB ABBA S Name 9 45 ob False Name 1 KOK ABB ABBA name Uploader 9 45 False Name Uploader 1 5 Object Icon 4 12 00 Connect Object Icon True Object Icon 1 KOK ABB ABBA Clas sified ty Object Type Structure 9 46 KOK ABBIABSA b T False Object Type Structure 1 PCCuploader 5 1 1 45 Minerals Ubrary Graphic Elements are object True Graphic Element i KOK ABS AEBA 2 Shelved Alarm List 5 13 2009 11 47 02 Connect This aspect category is used to c True Alarm and Event List 1 KOK ABS ABBA information 9 8 App_2 Alerm L 25 SourceMame Object Description Message Descriptio I AlarmState ActiveTime C KOK ABB ABBAdr ABB GRAPH 9 Engineering Workplace screen 3 2 4 Control Builder M Professional All the program code and I O definitions which were made was with the help of the Control Builder Control Builder is a programming tool that contains programming editors a compiler standard libraries for developing controller applications and standard hardware types in libraries for configuring the controllers The Control Builder also includes system firmware and common functions such as control system templat
32. ABB Inc 2013 System 800xA overview Available http www abb com product seitp334 6d1455f13733373ac1257289002d2631 aspx Accessed 14 March 2013 Berge J 2002 Fieldbuses for Process Control Engineering Operation and Maintenance Durham ISA Davies J 2008 Windows Server 2008 TCP IP Protocols and Services Washington Microsoft Press Festo Didactic GmbH amp Co 1997 Process Control System workbook Available http www pacontrol com download process control systems pdf Accessed 13 March 2013 Fieldbus Foundation 2006 description about Foundation technology Available 55 http www fieldbus org index php option com content amp task view amp id 23 amp Itemid 308 Accessed 7 March 2013 Freeport McMoran Copper amp Gold Inc 2013 Company profile Available http www fcx com company who html Accessed 3 March 2013 Funding Universe 1997 OM Group Inc history Available http www fundinguniverse com company histories om group inc history Accessed 3 March 2013 King M 2011 Process Control A practical approach Chichester Wiley Korpij rvi M 2013 Interviews with Korpij rvi Marko system programmer at Freeport Cobalt Ltd between 1 March to 1 June 2013 Syed M Soreanu G Falletta P and Beland M 2006 Removal of hydrogen sulfide from gas streams using biological processes Available http engrwww usask ca oldsite societies csae protectedpapers c0436 pdf Accessed 21 March 20
33. Andreas Dabnell DESIGNING AND PROGRAMMING AUTOMATION IN DISTRIBUTED CONTROL SYSTEM ENVIRONMENT Thesis CENTRIA UNIVERSITY OF APPLIED SCIENCES Degree programme of Information Technology May 2013 Centria UNIVERSITY OF APPLIED SCIENCES ABSTRACT Unit Date Author Kokkola Pietarsaari May 2013 Andreas Dabnell Degree programme Information Technology Title DESIGNING AND PROGRAMMING AUTOMATION IN DISTRIBUTED CONTROL SYSTEM ENVIRONMENT Instructor Pages M Eng Hannu Ala P nti 56 4 11 Supervisor M Sc Tech Matias Paloranta This thesis studies distributed control systems on a general level followed by experimental parts of designing and programming assigned cases The objective of those cases were to create control applications within the system for a hydrogen sulfide desuplhurization system and a sulfur dioxide distribution tank The thesis was commissioned by Freeport Cobalt Ltd chemical plant as part of plant wide automation system upgrade The goal was to create applications which would be efficient safe and user friendly The experimental part was completed with the ABB Industrial IT 800xA distributed control system and its composition was also used as a reference throughout the theoretical part of this thesis The control applications were successfully created and introduced to everyday use at the plant Key words ABB 800xA distributed control system programming control theory instrument para
34. D2G s G no21 lt s 4 6 Sp 1 26 8 6 1 PID 4 PI G Once the complete transfer function 1s resolved values can be inserted in order to study the stability of the system When calculated the result is in two parts the poles and the zero These values can then be inserted into a pole zero plot which is a graphical representation of the transfer function With this plot one can determine the stability of the system in a control event See Graph 17 for an example of a pole zero plot For example if the poles are a Imaginary result on the negative real axis it can be said that the system is stable but susceptible to oscillation Imaginary Part 1 0 5 0 0 5 1 Real Part GRAPH 17 Example pole zero plot 31 4 2 Practical programming phases The programming is done in the same order as the hierarchical structure of each project It starts with adding a new project folder which in this case was already made and designated as the Liuotto project After this appropriate control libraries are connected to the project As the Liuotto project was already made these were also readily connected The next phase was where programming work was initiated Graph 18 illustrates the steps from creating a new project to download Project s Configure controllers Programs Compile and download to controller GRAPH 18 Steps for building a project in ABB 800xA The practical
35. E id B 6 62012 LISATTY 06110 H2S KAASUPESURI 300263 1 A 16201 K NNETTYPID KAAVIOKSI PI KAA VID L 6 ss Nro Pym Mutos NimIi KAYTOSSA 6 5 FT LA 1 3 s H 21 1 2 ILMASTUS HIET J m YLIT YT N m amp A P 11 5 2012 USATTY 0312403333 0 0 0 D 58201 KAANNETTYPID KAAVIOKSI W 13 2 2009 LISATTY HAARAKEMIKAALILLE AY 14 17 2006 KUI JA KULW SIIRRETTY UUTEEN KAAVIDON 300241 0 AMY 23 10 2006 LIS TTY KOEMITTAUS 07312 2162775 5 IMUKONELINJOJA AMY lkk Wie hu ur veo xx Se I 2 APPENDIX 2 PI 7304 JN gt SA KU1 KU2 21 7 NRD 40 E25H2A gt lt TONS D 300241 0 PA N 7308 E PA N 21 lIN 25 7302 PS v 25 KULV E 7 25 1 25 7308 NRD 25 25 V 21 T NRD 5 1 502 VAROVENT 300241 0 1 7 NRD 25 E25H2A 21 1 KRD 4 0 7 D 300241 0 KAASAUS KULV S ILI N 21 NRD 40 E25H2A M LT 7305 21502VS ar 7307 5 7307 3 502 D D Gd Tu a oe 29 9 2003 JTS KORJAUS KULV KU2 LINJOJEN MUUTOKSIA 9 122002 JTS korjaus Kw
36. P7312 and P7306 found in Appendix 2 Once the storage tank is filled normal operating pressure is set back by an operator Other devices used are mainly for alarm and operation monitoring purposes Several emergency valves are used to cut the flow of hydrogen into the tank and let out hydrogen pressure from the flowlines Alarms for hazardous SO content in air are also used these measurements show the content as parts per million 5 1 1 Instrumentation The entire operation of the SO distribution process is based on using hydrogen pressure as the agent moving the sulfur dioxide Therefore no electric motors are needed The hydrogen pressure in the pipeline 1s at a constant value of 12 6bar when it reaches the SO tank The pressure is then regulated by control and hand operated valves As seen in Table 3 there are mostly pressure measurements for the purpose of alarms and interlocks 42 TABLE 3 Instrument list of the SO distribution tank Tag Description JA KULV emptying O Liquid SO2 station emergency close AO ange jUnit J EE E SO2linepressuret 1 E nunt BENE 1 p on off m olo z 2 S N 1 1 3 m mbar 20 25 ppm 50 100 50 100 50 100 0 80 O O O 1 H EE ___ 0 10 10 25 il SO2 pressure after break film P7303 Liquid SO2 tank pressure 1 NEN Ea
37. PG PG 1 D NETTE 4 2 Sp 1 PG 1 D An additional PID controller is needed for the regulation of the correct mixture of sodium hydroxide This is done by measuring the pH and flow values of the solution circulating in the tower these values work as separate feedbacks for two controllers The controllers steer a control valve letting sodium hydroxide flow to the tank in the right amount The sodium hydroxide pressure is constant and susceptible to deviation due to its usage in other processes as well therefore a more stable control method was needed Two PID controllers were applied one measuring the pH value and one the flow of sodium hydroxide As shown in Graph 16 the controller measuring the pH value is tagged Q6107 primary Its output is connected to the setpoint input of the other controller tagged F6111 secondary that measures the flow rate F6111 output finally guides the control valve in order to achieve the appropriate flow This control method is called cascade control The stability of the control system with this method is increased because disturbances from rapid changes of the secondary controller will not affect the primary controller 29 lt lt lt MUI
38. S T T i T LI d OO 4 E H oa A H q4eq ag 2 P BMSI 1 qe z gt 1 T suma sss _ 1 at sel a LE 1 1 8 a l RU rtt S NN Ent lai tosi is NE SEN RS ki DS ail yl S TE 1 51 18 A Tm ps mg eie pg gs Ret ng fgg pg a ag E S S bel b Pe er er ere J 28 LIII Il ILE ALI qz cy E PS1 FST a d o AB APe B EJ ta 118 113 B 107 9 JHT 8506 LIM 90 2d k kH Ss J tie i k 8l k Hr Hi E APPENDIX 6 Freeport balt Automaanoryhma 21 2 Lukitukset Kaasun purku ulkoilmaan mik li imulinjassa ei tarpeeksi alipainetta Positio Lukitus Kuvaus Positio Lukitus Kuvaus Lukituslista Sivu 1 1 APPENDIX 7 21PES2 ryhm k ynnistys Positio Toiminto Kuvaus F6111 Laimea NaOH gt PES ol NM an 21PES2 imulinjan paineensaato s wem a Pys ytys p invastaisessa j rjestyksess M6139 k ynnistysehtona on ettei pinta 16112 MIT ole liian matala L2 S ili ssa t ytyy
39. achieve this goal Redundancy is the practice of duplicating critical system functions in order to increase the reliability of the system As seen in Graph 7 all the network components cables switches routers and network adapters are duplicated Paloranta 2013 ETT misi m dum Primary Network E Ar AE SS Secondary Network _ L t E nie ayer e ay GRAPH 7 Physical view of a full redundant network ABB Inc 2012a As long as the primary network paths are working all process data is sent on that network The secondary network normally carries no user traffic This guarantees that network performance is not affected after a network fail over Both supervision of network paths and fail over between Primary and Secondary networks are performed by RNRP Redundant Network Routing Protocol RNRP is an IPv4 routing protocol developed by ABB It is specially designed for use in automation networks with limited topology ABB Inc 2012a 14 3 2 Operations software End user configuration and programming of the DCS is done by the help of supplier developed applications This section explains functions of different applications Because the experimental part of this work was done with the ABB System 800xA DCS its applications will also be used as a reference The main configuration tools which also were utilized to complete this work are the Engineering and Operator Workplaces Cont
40. ank for transfer via pipelines to where needed Siren Jarmo 2013 From the automation perspective many safety features were needed because of the extreme toxicity of sulfur dioxide Sulfur dioxide causes irritation of eyes moist skin areas and respiratory tracts at 20ppm coughing at 50 100ppm and in high concentrations more than 400ppm respiratory distress and risk of death Long time exposure can aggravate susceptibility to respiratory diseases Sir n Jarmo 2013 502 distribution to plant processes Nitrogen Pressure release Pressure release GRAPH 25 Simplified operational description of the SO distribution tank 5 1 Operation principle The sulfur dioxide is brought to the site by a tanker truck Two main hoses are then attached to the tanker one for hydrogen pressurization of the truck container and another for transfer into the main sulfur dioxide distribution storage tank The hydrogen pressure in 41 the storage tank must be lowered in order to create a higher hydrogen pressure in the truck tank An operator pushes a button in the operator environment screen of the SO tank that automatically lowers the hydrogen pressure value in the tank This forces the liquid sulfur dioxide from the truck into the storage tank Control of the hydrogen pressure in the main storage tank is controlled by two PID loops one for hydrogen feeding and another for outgoing SO from the tank These PID controllers are tagged
41. arly impossible without long plant downtime periods The purpose of the experimental part of this thesis was to design and reprogram the automation of two entireties which were a hydrogen sulfide desulphurization system and a sulfur dioxide distribution tank The goal was to successfully build control applications for both and to create simple control graphics for the use of the process operators Throughout the practical work process operators were considered as the end users of the applications and their needs and efficiency was considered a priority Even though the applications could be complex the visibility of these applications to the operators should be clearly structured and simple to use Those factors would be facilitated by clear documentation and easily interpreted process graphics This work is divided into three main chapters First general theory of distributed control systems and related devices methods and programming were studied The theory part should give a good introduction to the skill and knowledge that was required to complete the practical work of this thesis The practical work of designing and programming automation in the system is discussed in the two following chapters 4 and 5 2 FREEPORT COBALT LTD Freeport McMoRan Copper amp Gold Inc NYSE FCX is an international mining company with headquarters in Phoenix Arizona FCX operates geographically diverse assets with proven and potential reserves of copper
42. as four different tiers of networking each with different technology device I O subsystem controllers and plant wide integration to to business applications The modern configuration however is to have an Ethernet TCP IP network for the communication between the computer terminals and the servers TCP IP is also used to link the controllers to the connectivity server In decentralized I O a fieldbus normally profibus DP is used for communication between the master profibus Communication Interface in connection with the controller and the remote slave I O unit PI organization 2013 Traditionally a common method of sending information from an instrument to the system Is done by analog 4 20mA current loops 4mA representing the lowest measurement value and 20mA the highest This requires a minimum of two wires per instrument which in large plants result in even kilometers of current loop wiring Information received by the 4 20mA method is limited to measurement value only Foundation fieldbus for example is a technology addressing these issues FF connects the instruments in a single all digital serial bus The increased electronic capabilities of the instruments allow more information to be added to the data package sent in the bus for example electricity consumption data and maintenance notifications A disadvantage in the FF system and other fieldbuses is the more vulnerable structure if the bus is severed in one spot all the instrum
43. der structure and connect standard libraries to it The libraries connected were the same used elsewhere in the plant in other words the BMI library components In addition there were some customized libraries created for use in Freeport Cobalt specific cases which were also added These customized libraries contained for example code for solution samplers used around the plant Next the data types for each device were defined Here the first problems were encountered with the documentation of the devices connected to the AC2 controller to which all the instruments of the two device entireties were connected to There were significant conflicts between the information found in the circuit and P amp I diagrams compared to the existing process graphics and code of the two devices These problems were resolved when ABB support personnel was contacted and asked to import the code from the old AC2 controller into a Microsoft Excel base From this Excel file the actual used real time parameters and devices could be found The documentation was updated along the programming work These conflicts were most likely caused by lack of communication between plant personnel small changes to program code had been performed by several employees and subcontractors over the years and those changes were not forwarded to the circuit diagram designers It was stated that up to date drawings would be very important for safety and operability If a hazardous event wo
44. e interlock was to be put in to effect after the timer block gives an output signal if not the interlock was not to be in effect GRAPH 23 TOf Function Block timing diagram 36 Ho152 TOLE In uot KRagsupe suri POLOS OU MV Hz Value PT TimelOs xr 1161321021 Chen 101125 Ka supSsuri H01352 15N 1B1 true else 101125 K supesuti H6132 101B1 lt false end rr Another interlock was needed for the pump tagged M6139 The pump circulates the fluid from the tank located at the bottom of the scrubber to the showers spraying the gas The interlock triggers when the fluid level in the tank indicated by measurement L6112 MIT reaches the limit L2 set at 10 This interlock was programmed because the pump can sustain severe damage if it operates without fluid running through it The code is similar to the one used previously Mod so TORE in nob 10 2315716117 MISS Value PI TimelOs Le Molo TOPDISQ chen 10 25 61 39 kia TD S true else TO H S K supesut1 M6159 1n 151 false end 1f A document explaining these events was created and placed as an aspect in the engineering workplace A link to this aspect was then created in the graphics screen as a button Documentation is important to be always available to give operators an overview of how the system works and in respect prevent confusing situations from occurring The interlock document can be seen
45. ents and actuators connected stop working This raises the need for redundancy of the fieldbus communication Fieldbus Foundation 2006 FOUNDATION fieldbus Cl Profibus Cl Controller E E l Profibus DP GRAPH 3 Comparison of instrument connection setups 3 1 2 Servers The servers in the automation system are central information data and communication hubs As shown in Graph 2 several different types of servers are used Each has it s own purpose and function to streamline and clarify operation This paragraph explains the functions of different servers Please keep in mind that the setup and naming policies vary by system supplier and this text is to give a general perception of server functions in an automation system DNS Domain Name System is a hierarchical name service for domains and IP addresses The DNS service enables client nodes on a network to register and resolve DNS domain names and to find domain controller services DNS can be used for finding the IP address of a node which is only known by name address resolution and for finding the name of a node which is known by IP address name resolution DNS can also be used for finding domain controller services 1 e which node runs a certain service for the domain ABB Inc 2012a Aspects servers run the intelligence of the system Aspects are informational items associated with objects such as I O definitions engineering drawings pr
46. equence start bar The final revision of the graphics screen can be seen in Appendix 3 4 2 2 Interlocks An interlock is introduced in conditions where a device is not allowed to be started shut down or operated before certain conditions are met Interlocks are mainly used for enforcing safe operation and durability of system devices In the scrubber one important interlock was needed for the valve tagged H6132 The valve operates as a release valve in case the vacuum of the pipeline fails This failure might occur for example if the pump M6138 ceases operating If there was no release valve the toxic gases would build up indoors The valve was programmed to open and let the gases straight outdoors without going through the scrubber when the pipeline pressure reaches a high limit of 2 0mbar The valve does not automatically close once opened For the operator to manually close the valve again the pressure must be within the acceptable range between 49 0 and 4 mbar The code was written in ST under the H5S scrubber folder First a timer function block was introduced for the purpose of hysteresis This means that if a sudden spike like a signal interference occurs the valve will not unnecessarily open The timer creates a 10 second delay before the valve is opened and interlock put in to effect Graph 23 shows the behavior of the block when an input signal is introduced The following code is a conditional statement that defines that th
47. erating system 16 3 2 3 Engineering Workplace The Plant Explorer or Engineering Workplace is used to create delete and organize aspect objects and aspect within the 800xA System It organizes the aspect objects in structures according to functionality and location Plant Explorer is the main tool used by engineers for exploring and building hierarchically structured models of a plant or system The structures represent different views of the plant The following are examples of different types of structures Functional Structure displays the plant from the process perspective It is an overview of the functionality of items in the plant It is used for operation of the plant Location Structure displays the physical layout of where equipment is located in the plant It is primarily used for maintenance tasks Control Structure displays the control network in terms of networks nodes fieldbuses and stations ABB Inc 2012b All the entities included in a plant are represented as objects for example valves motors controllers and tanks These objects have relevant information stored in aspects as shown in Graph 9 This information is for example process graphics control dialogs and alarm pages In Graph 9 the aspect objects are in the left column and a list of the aspects connected to it is in the right column Below it the screen shows details of the selected aspect in this case an alarm and event list The aspects are stored in
48. es task supervision security and access management ABB Inc 2012d At Freeport Cobalt the code is divided in several different project folders by the geographical placement of the controllers The one that was worked with was called Liuotto which is the raw material refinery of the plant The project breaks down in a tree formation similar to Windows Explorer The tree also represents the hierarchical structure of the project from top to bottom Details of the programming sequence can be found in section 4 1 The project view screen can be seen in Graph 10 The project contains three main folders Libraries contains a storage of reusable programming elements that can be used In the program code and hardware definitions 18 Applications contain the device tag definitions and program code At Freeport Cobalt there is one application for each controller Controllers folder contains hardware definitions 1 e the setup of the controller rack I O connections and the controller tasks which define the priority and interval time in program execution File Edit View Tools Window Help oOo F S gt Libraries E Applications _ m M App 1 ACI Norman App 2 AC2 Normal In Connected Libraries Data Types Control Modules Co Alloy amp C21 Co Alloy E Controllers 23 Ac e Hj Classified infromation Be AC Connected Applications Connected Libraries Hardware AC 800M Tasks
49. esuplhurization system graphics GRAPH 23 TOf Function Block timing diagram GRAPH 24 Group sequence status display GRAPH 25 Simplified operational description of the SO distribution tank GRAPH 26 SO distribution tank control loops GRAPH 27 Princible of the code used to calculate consumption of SO GRAPH 28 ShiftRegisterReal Function Block GRAPH 29 Timing diagram of PulseGenerator Function Block GRAPH 30 Flowchart describing the events in the automatic setpoint drop TABLES TABLE 1 Examples of basic language functions TABLE 2 Instrument list of the H2S desulphurization system 43 44 44 48 50 51 54 13 15 17 18 21 25 24 26 27 29 30 31 32 33 33 34 35 38 40 42 45 46 46 48 19 26 TABLE 3 Instrument list of the SO distribution tank TABLE 4 Function Blocks used in the consumption measurement code 42 47 1 INTRODUCTION Process automation is the control of blending and treatment of raw materials that result in a continuous stream of product This is achieved by depending on the plant size hundreds to tens of thousands of sensors constantly measuring and monitoring process quantities These sensors are connected to the distributed control system which processes the information in a way defined by program code Once processed the system controls actuators which change the process flow The most essential purpose of process automation is to maximize production efficiency at as
50. in Appendix 6 4 2 3 Cascade control connection This section examines the programming method that was used in order to achieve the cascade control studied in section 4 1 2 Two separate PID control modules were created and parameterized in the Control Builder The PID s were then added to the process 37 graphics where the cascade connection was indicated by a dotted line between the two elements It still had to be defined that the actual setpoint of the controller F6111 is set from the output of controller Q6107 This definition had to be programmed in ST language in the Control Builder as shown below Q6107 gt F6111 IO H25 Kaasupesuri F6111 In ExtRefAutol PID F6111 MIT Parameters Max I0 PID F6111 MIT Parameters Min IO PID Q6107 0HJ Value 100 0 6111 Parameters Min The first row of the code is to connect the output value of the PID Q6107 to the external reference setpoint of controller F6111 However in order to do this the value fed into the external reference must be scaled from the percentage output of Q6107 to match the value in the measurement range of the controller F6111 For example if the measurement minimum and maximum values of the secondary controller are 120 and 200 it means that the range is 80 200 120 80 When the output of the primary controller is at 10 this multiplied with the range value of the secondary controller results in 8 10 80 8 Finally
51. in Graph 6 In the third level is the 15 information related to a specific interactive object in the unit screen For example the operator can open text documents which explain the function of group starts motors and valves ABB Inc 2012b By clicking on a dynamic object on the process screen a faceplate appears The faceplate shows detailed information of the selected object such as the current measured process value and its range and alarm limits Operators can also manually control the selected object from the faceplate by setting the device on manual control if allowed in the programming A faceplate of a control loop can be seen in Graph 8 The bottom buttons are used to select a control method automatic manual or external control The abbreviations are MV Manipulated Variable SP SetPoint Dev Deviation and PI Proportional Integral More detailed information about control loops can be found in section 4 1 2 4 F8904 Faceplate mee Faceplate lt GRAPH 8 PI Control loop faceplate Navigation between different menus is usually done by tabbed navigation Tabs are located at the top of the screen and provide quick access to important graphics The tabs at Freeport Cobalt are quick links to different plant sections such as refining and chemicals production One could think of these as his favorite sites on an internet browser this makes it easy for a new user to relate to the op
52. interval was introduced to the other sampler with the help of a Timer On Function Block The Timer Function Block gives an output Boolean signal after a set time delay has passed The output of the timer is set as a condition for enabling the other shift register This way the shift register only starts operation when the timer delay is finished This delay is only initiated once when the controller starts operation Below in Table 4 and the code following is the final Function Blocks and code used to achieve this measurement TABLE 4 Function Blocks used in the consumption measurement code W7302 Pulssi PulseGenerator Sample interval W7302 Pulssi2 PulseGenerator Sample2 interval W7302 Tall RegisterReal 1 Sample1 shifting to variable W7302 Tall2 RegisterReal 1 gt Sample2 shifting to variable W7302 Viive oample2 enabling delay 48 if w7302 wviive Q then w7302 Pulssi2 Enable 1 end if w7302 viive In true PT 502 sailio Times D 105 w7302 Pulssi PulseTime 502 sailio Times D 15 Enable true MN PeriodTime 502 Sailio Times D 205 w7302 15512 PulseTime 502 sailio Times D 15 Enable w7302 Pulssi Enable PeriodTime 502 Sailio Times D 205 J w7302 Tall In 1 I0 AIS wWw 302_MIT Signal Value Write w7302 Pulssi out Out 1 gt w7302 Naytel w7302 Tall In 1 IO AIS WwW7302 MIT Signal value Write w7302 Pulssi2 0ut Out 1 gt w7302 Nayte2 w7302 Uusi
53. is assigned to Syntax P1 amp P2 P3 amp N4 P1 AND P2 OR AND NOT P4 AND before OR N din BMI DINT N nenarifiad IIN Groun Stan ta artivata i diirinn ctartinn 1 000 dirina etanninn 1901 1909 N nat 4 3rnGtan13 4 gt Parameters Row 2 Col4 KOK ABB ABBAdmin GRAPH 19 Control module parameters of PID controller Q6107 The hardware is modelled at the bottom of the Control Builder screen The controller that was worked with was labeled AC2 In the folder AC2 was the application folder libraries folder hardware folder and tasks folder The application folder tells the controller which application s it will be running In this case App_2 which was previously created was connected Libraries folder contain a set of predefined hardware types stored in standard hardware libraries These libraries contain definitions for devices such as controllers I O modules CI modules and more Hardware folder models the actual hardware that is connected to the controller The folder opens a hierarchical view first of the controller rack Graph 20 and under each CI module are the connected I O clusters Graph 21 to which the actual instruments are connected 33 GRAPH 20 A controller rack with several CI modules connected ke aoe ob bb GRAPH 21 An I O cluster with redundant fieldbus slave units Meanwhile the researcher was designing the automation of the s
54. is done from these terminals The information from the plant is presented in graphical dynamic user interfaces which are made to easy to understand and operate Topologically the computers are connected to the server client Ethernet network as clients in a ring configuration An example of process graphics can be seen in Graph 6 By clicking on an object on the screen the operator can inter alia change automatic control setpoints Operators usually only have access to their Own respective site graphics and experts are assigned to each process section ABB Inc 2012c Paineilma mm 2 37PN11 pysaytys lukitusraja t t 1 auhde 37SPR6 GRAPH 6 Process graphics display Trendi 5 Engineers can configure the system either from special engineering workstations or any client station by using different user account Creating process graphics and writing program code is done by special manufacturer supplied software which are examined further in section 3 2 ABB Inc 2012c 13 3 1 6 Network and device redundancy In a continuous process such as Freeport Cobalt s manufacturing process even short unscheduled plant downtimes can be very costly The different process sections are linked together and shutdown of one interrupts material flow to the other This can effectively stop entire plant operations The goal is to keep the uptime at a minimum of 98 07 1 one week of scheduled downtime per year Redundancy helps to
55. it of 2 6m or the weight of the tank at a high limit of 60t When either of those conditions would be met the interlock was to be put into effect This would cause the valve P7305 1 to close feeding of nitrogen and the valve P7305 2 to open 50 5 1110 7305 1 not IO AIS W7302 MIT H2 Vvalue 50 s ili P7305 IN IB1 not IO AIS L7305 MIT H2 Value IF 15 7 313 MIT Signal value IO PID P7306 MIT Value lt 1 then 0 502 S ili P7305 In IB2 false else TO 502 s ili P7305 IN IB true end if 45 Additionally to the DCS interlock there are also emergency stop buttons in the field which close and open valves by direct electric connections When a stop button is pushed the valve HV7308 1 closes the feed of nitrogen to both the tank and the truck depressurizes the pipelines by opening the valve HV7308 2 and closes the feed of liquid SO to plant by opening HV7308 3 These valves have limit switches indicating they have been closed or opened The limit switches are connected to the DCS by digital inputs and are displayed to the operator in the graphics screen for immediate information about this event The circuit diagram of this can be seen in Appendix 10 5 2 3 Calculated consumption measurement An important fact to know about the SO tank was the total consumption of the sulfur dioxide This would show the amount of sulfur dioxide used by the plant processes at
56. ivates the step after the transition An example of this can be seen in Graph 12 where Trl 2 3 are the transitions ABB Inc 2012 25 Tr2 Start mixing 33 Tr GRAPH 12 A sequence structure ABB Inc 2012e Even though SFC has many advantages as a design and structuring tool it is not a complete programming language Therefore the transition conditions and action descriptions have to be programmed with one or more of the other available programming languages In Graph 12 for example there is code written inside the Init box At Freeport Cobalt the language can be either ST or FBD ABB Inc 2012e 3 4 Summary This chapter covered the aspects which were needed to be studied and internalized in order to understand automation in process industry as a whole Architecture and DCS structure was studied as well as related devices and networking methods Insights to the programming tools were given and their practical purpose discussed Finally some of the IEC 61131 3 programming languages were looked into and their advantages and disadvantages resolved Throughout this paragraph references to Freeport Cobalt Ltd s use cases were given in most of the examined subjects for purpose of relation to real world cases 24 4 AUTOMATION H2S DESULPHURIZATION SYSTEM The first part of the practical work of this thesis was to design develop and reprogram the automation of the hydrogen sulfide desulphurization system
57. l Man H6132 H25 Kaasun purku ilmaan Central Man 06107 PES2 pH Alarm Seguence ElAuto _F6111 Laimea NaOH gt PES IT Alarm Sequence 16139 Sequence Man P5108 PESZ imulinjan paine Sequence 16138 21PUH18 MOT Off Sequence GRAPH 24 Group sequence status display 4 3 Summary This chapter covered in addition to operational insight of the H2S desulphurization system the sequence and methods with which a working automation application is created in the ABB s 800xA DCS Also in some extent in other DCS systems as well The practical programming phases section also discussed the need for interlocks and control loops and related theory Some of the program codes for example interlock codes and cascade control codes are not specific to the H2S scrubber and can be utilized in other applications as well 40 5 AUTOMATION OF SULFUR DIOXIDE DISTRIBUTION TANK The second practical work in this thesis was to design develop and program the automation of a sulfur dioxide distribution tank Sulfur dioxide is a colorless pungent smelling irritating gas that is in pressurized liguid form in the storage tank At Freeport Cobalt sulfur dioxide is used in processes to enhance dissolution of raw materials Usage of the substance is mainly continuous and is guantitatively approximately 0 2 0 7 t h depending on the raw material situation As shown in Graph 25 dry nitrogen gas is used to pressurize the SO t
58. little cost as possible Due to the increasing complexity of manufacturing methods control of rapidly changing conditions for example some tasks would not be possible without high level modern automation Because of these variables the level of automation in process industry is constantly on the rise and engineers involved must specialize in increasingly narrower areas of expertise Also in the case of this thesis the automation system consists of a large amount of technologies from different areas of engineering and sciences For example information technology is applied in communications and servers and electrical engineering is applied in variable frequency drives and motors This thesis does not focus solely on a single area but studies the composition of distributed control systems on a general level and the practical configuration of control applications In order to successfully design and program automation applications an extensive engineering knowledge background of the system has to be achieved This thesis was commissioned by Freeport Cobalt Ltd a chemical plant located in Kokkola Finland The plant has currently two different automation systems in use the older ABB Advant and the newer ABB 800xA The lifecycle of ABB s Advant system is nearing its end and is being replaced by the 800xA The update process has been ongoing for a while and is completed in sections at a time This is because updating the whole system is ne
59. metrization control application Centria UNIVERSITY OF APPLIED SCIENCES TIIVISTELM OPINNAYTETYOSTA Kokkola Pietarsaari Toukokuu 2013 Andreas Dabnell Tietotekniikan koulutusohjelma Ty n nimi AUTOMAATION SUUNNITTELUA JA OHJELMOINTIA HAJAUTETUSSA OHJAUSJ RJESTELM YMP RIST SS Ty n ohjaaja Sivum r Ins YAMK Hannu Ala P nti 56 11 Ty el m ohjaaja D Ins Matias Paloranta T m opinn ytety tutkii hajautettuja ohjausj rjestelmi yleisell tasolla jota seuraa kokeelliset osuudet automaation suunnittelusta ja ohjelmoimisesta m ritellyiss tapauksissa Tapaukset olivat luoda j rjestelm n sis ll ohjaussovellukset rikkivedyn rikinpoistoj rjestelm lle sek rikkidioksidin jakelus ili lle T m n opinn ytety n tilasi Freeport Cobalt Oy kemikaalilaitos osana laitoksen automaatioj rjestelm n uusintaa Tavoitteena oli luoda sovellukset jotka olisivat suorituskykyisi turvallisia ja k ytt j l heisi Kokeellinen osuus suoritettiin ABB Industrial IT 800xA hajautetulla ohjausj rjestelm ll sek sen rakennetta k ytettiin my s viitekehyksen teoriaosuudessa Sovellukset saatiin onnistuneesti luotua ja ne otettiin jokap iv iseen k ytt n tehtaalla Asiasanat ABB 800xA hajautettu ohjausj rjestelm ohjelmointi s t teoria instrumentoinnin parametrointi ohjaussovellus ABBREVIATIONS DCS DNS OPC CPU
60. nd falling edge is used Level 0 might represent a voltage value of 0 2V and 1 a voltage of 3 5V In some cases the signal is inverted in the program code i e SV is interpreted as a logic value of 0 An example of a negated Boolean input can be seen in paragraph 3 3 1 This is usually used for security purposes as there is no way of knowing if the signal wire is cut if the signal is normally at OV In process automation digital signals are mostly used for limit switches which trigger system alarms and events University of Alberta 2003 Analog signals are current loops with a current value between 4 20mA The signal constantly circulates between the I O module and the field device Usually the signal is used to measure process quantities such as fluid level The actual level is scaled to 4 20mA 4mA representing zero value and 20mA max level The 4mA live zero helps to detect failures in the loop When the current drops to OmA it is an indication of either 12 instrument or wiring failure The signal goes through an A D converter in the analog I O module for interpretation by the program code In a 16bit converter for example the signal is converted to a decimal value of 0 65536 or 32768 32768 National Instruments Corp 2012 3 1 5 Workstations and process graphics Operator and engineering workplaces are PC based computers which have the purpose to work as HMI s Supervision and operation of the site
61. ne Interface for the SO tank was started by adding a new aspect in the Engineering Workplace This graphics screen was created to correspond 44 to the PI diagram seen in Appendix 2 The screen shows the tank as the central part of the system and flowlines are represented as different colored lines connected to and from it This should make it easier to get to know the system quickly without prior training of it The dynamic objects instrument measurements valves and control loops were finally added to their corresponding positions for easy interaction and monitoring by the operators System interlock and operation description documents were written and created as button links for quick interpretation of interlock events and operation overview The created graphics screen can be seen in Appendix 4 The interlocks which were needed for this system can be found in the next section The operational document explains the programming principles i e what happens when the T ytt button on the screen is pressed These two documents can be found in Appendices 8 and 9 5 2 2 Interlocks For this system two interlocks were needed for the filling operation of the tank To prevent overfill of the SO tank an interlock cutting the nitrogen feed to the truck was programmed The interlock had to have two conditions If the pressure deviation between the tank and the incoming nitrogen is too low below 1 bar or if the tank level was at high lim
62. nnected a new Remote Desktop connection was formed from the terminal server to a automation system engineering client from whereof the screen s captures are taken ABB Inc 2012a Remote Client Plant Network Firewall VPN Gateway System Network Terminal Server Terminal Server GRAPH 4 Examples of remote client access ABB Inc 2012a 10 Information Management servers log historical process data This data is trends from the process electrical history alarm and event history and production data This information can also be transferred into a plant wide database system Freeport Cobalt does not utlize separate Information Management servers history logs are gathered in a separate RTDB system via the connectivity servers ABB Inc 2012a OPC Open Process Control assures interoperability between devices from different manufacturers OPC server converts data from different sources into a standard based OPC format This can be utilized in connecting and controlling an automation entirety from a different supplier than the main system This standard is managed by the OPC foundation OPC Foundation 2013 3 1 3 Controller functions Process Automation Controllers are essential to any process automation system Controllers consist usually of a CPU PSU and I O and communication modules Controllers are very dynamic and modules can be added and removed easily Controller CPU s are digital
63. ocess graphics reports and trends that are assigned to each object in the system These servers are the most important ones at Freeport Cobalt if they fail to operate so does the entire plant Because of this two redundant pairs are applied and separated geographically in order to ensure constant operation 6 ABB Inc 2003 Connectivity servers provide access to controllers and other data sources Several groups of connectivity servers may exist in a system each serving one set of data sources Examples of services that run on a connectivity server are OPC related services and connections to database services In Graph 2 the secondary connectivity server connects another DCS via a fieldbus This enables control of two separate systems from the same operator terminals At Freeport Cobalt there are several connectivity servers applied each collecting data from different sources For example one is used exclusively for Foundation Fieldbus connectivity and data ABB Inc 2012a Terminal servers handle remote desktop connections and user authentication Users can have different levels of access permissions the terminal server restricts clients according to the level of access they have In Graph 4 remote access is shown from inside the plant network and from the internet For example the screen captures in this thesis were captured by connecting to a terminal server from an office network computer by Windows Remote Desktop Once co
64. ommonly in automation IEC 61131 3 standard Structured Text a programming language part of IEC 61131 3 standard Sequential Function Chart a graphical programming language used to describe sequential behavior IEC 61131 3 International standard for programmable logic controllers includes LD FBD ST IL and SFC ATmospheres EXplosives an EU directive describing allowed work and equipment in an explosive atmosphere Real Time DataBase a relational database designed for process information management and history recording ABSTRACT TIIVISTELM ABBREVIATIONS TABLE OF CONTENTS 1 INTRODUCTION 2 FREEPORT COBALT LTD 3 DISTRIBUTED CONTROL SYSTEM 3 1 System architecture 3 1 1 System communications 3 1 2 Servers 3 1 3 Controller functions 3 1 4 I O signals and module types 3 1 5 Workstations and process graphics 3 1 6 Network and device redundancy 3 2 Operations software 3 2 1 ABB System 800xA 3 2 2 Operator Workplace 3 2 3 Engineering Workplace 3 2 4 Control Builder M Professional 3 2 5 Graphics Builder 3 3 Programming languages 3 3 1 Function Block Diagram 3 3 2 Structured Text 3 3 3 Seguential Function Chart 3 4 Summary 4 AUTOMATION H2S DESULPHURIZATION SYSTEM 4 1 Operation principle 4 1 1 Instrumentation 4 1 2 Control loops and control theory 4 2 Practical programming phases 4 2 1 Process graphics display 4 2 2 Interlocks 4 2 3 Cascade control connections 4 2 4 System seguence start and stop 4 3 Summar
65. on is important for cost 53 effectiveness Classic control theory and its utilization at Freeport Cobalt were studied but the PID parameters gain integration time and derivation time were mostly predefined from the previous application and there was no need to tune the controllers The retuning of the PID controllers might thus require further study at the plant The resulting control applications made the operation of both systems more efficient and safe The operators would now have more tools to ease the operation of the systems and also have quick access to documentation regarding the interlocks and other matters related to operation procedures The added interlocks will contribute to the safe operation of the systems if abnormal conditions occur in the future 54 REFERENCES ABB Inc 2012a System 800xA 5 1 Network Configuration User manual ABB Inc 2012b System 800xA Engineering 5 1 Engineering and Production Environments User manual ABB Inc 2012c System 800xA Engineering 5 1 Process Graphics User manual ABB Inc 2012d System 800xA Control 5 1 AC 800M Planning User manual ABB Inc 2012e System 800xA 5 1 System Guide Functional Description User manual ABB Inc 2003 released system document Available http www05 abb com global scot scot296 nsf veritydisplay efa585f87b76f1a3c1256f670 0017b0d Sfile 3bus092080r0001 en industrial it system 800xa architecture overview pdf Accessed 10 March 2013
66. p M6138 input The last step of defining the devices to the system was the configuring of hardware and physical I O connections Editor Edit View Insert Tools Window Help kk 4 0 A o SS Name Data Type Initial Value Parameter Direction Description 1 Name string 24 Name 06107 unspecified INIT Tag name of the PIDCtrl allowed deliminators and no blanks or allowed 2 Description string 40 Description Pep IN Description text of the PIDCtrl 3 IO PIDCtrlData 10 H2S_Kaasupesuri Q6107 unspecified IN OUT PIDCtrlData Variable 4 Group GrpDrvCon default 10 H2S_Kaasupesuri GrpDrvCon unspecified IN OUT Connection to control module GROUP sequencer 5 PCC PCCComData Default unspecified IN OUT Interlock Bus PriorityCommand Interlock to motors valves or groups 6 PCCAEListFrcEn bool false unspecified IN PCC AE List handling forced to be always on and not controlled by PCC parent T MV ReallO IO PID Q6107 MIT unspecified IN OUT Measured process value e g an AIS or AIC signal Please use IO FilteredSignal when noisy signal 8 FieldDeviceStatus dword 16 80C0 unspecified IN 2nd DWORD for MV Field Device Status Supervision e g Profibus PA Devices etc If value equals 16 80 0 the FPL in 9 OUTP ReallO IO PID Q6107 0HJ unspecified IN OUT Output signal of the PID Loop Use IO GRP PID Out OUTP
67. principle For the efficient operation and monitoring of the system a set of devices are needed and are to be automated Each device is connected to and controlled by the DCS To explain the operation of the system devices they will be referred to with the help of device tags found in Appendix 1 The pump M6138 creates a vacuum in the pipeline and sucks the contaminated gas into the scrubber tower This pump can be seen in Graph 14 labeled as 21PUH18 The pump is controlled by the PID controller tagged P6109 additional examination of this in section 4 1 2 Once in the scrubber the gas is sprayed with the cleansing solution of water and sodium hydroxide that is pumped from a container in the bottom of the scrubber The circulation pump is tagged M6139 Some of the cleansing solution is evaporated with the gas and must be constantly refilled Water is pumped in to the container with a constant rate of approximately 300 I h To get the right solution sodium hydroxide ratio in the water must be suitable The sodium hydroxide flow in to the container is kept at the correct amount with the help of the PID controller tagged F6111 this is also more closely examined in section 4 1 2 The treated gas is then let out in to the open air In addition to the control loops measurements which do not directly control anything are also needed These measurements allow closer monitoring of the system operation that facilitates making the system more efficient
68. rammed to ease this operation The button automatically lowers the pressure instead of manually lowering it thus ensuring correct operation values Operator friendliness is the key for effectiveness no matter how good the automation programming is it will always be the operator who is responsible for the operation of the system The programmers will not constantly be around to supervise the operation it is the task of the operators This emphasizes the need for clear simple process graphical displays or Human Machine Interfaces The created applications were made as easy to use as possible for example the automatic control loop setpoint drop could have been done manually by separately setting the setpoints to the appropriate values However this would have left room for more human error as there are more things to take in to consideration Now that the button is programmed the only thing the operator needs to do is click one button that clearly states what it does easy and efficient Also the documents found in the appendices were solely made to aid the operators If there is a confusing situation they have quick and easy access to information related to the system For example from the interlock lists they can quickly see what will cause interlocks and how to prevent them from happening The PID controller loops were not thoroughly studied in this thesis They have a very essential role in process automation and their effective operati
69. rmation is collected in a 240 byte package in the fieldbus slave unit The information packages are collected to the fieldbus communication interfaces which are in a series with a controller The controller finally reads the CI units in fixed intervals Data from the controllers is read via the connectivity server from which the operator terminals can monitor and control relevant plant data Paloranta 2012 TTA ERI Operator Operator Operator Operator workstation workstation workstation workstation Terminal Client i Desktop Client s oo sos s oo w 58 o a s _ a 22 li li li li Engineering Engineering workstation workstation Firewall Connectivity Server main MasterBus 300 em Control Network Ethernet TCP IP Controller 1 Controller 2 Hi J 9 T Controllers Profibus DP Instrumentation 1 0 modules Variable frequency drive 1 0 modules hie i Controller und id Process Instrumentation Process electrical AC motors Process Instrumentation Process electrical motors GRAPH 2 Example DCS architecture adapted from Paloranta M 2012 3 1 1 System communication Process automation systems utilize several different communication protocols and the topology varies by supplier and plant A DCS can often have in all as many
70. rol Builder M Professional and the Process Graphics Editor 3 2 1 ABB System 800xA The Industrial IT Extended Automation System 800xA was first released in December 2003 It is the main automation system in use at Freeport Cobalt Ltd and very popular in other process industry plants as well Specifically the System 800xA incorporates process control production management safety discrete logic and sequence control advanced control information management smart instrumentation smart drives and MCCs asset management and document management capabilities in a singular virtual database environment ABB Inc 2013 3 2 2 Operator Workplace The production environment represents the current approved state of the system The state consist of the solution running in the controller and the graphics alarm lists and trend displays used by the production system This is the environment the operators use to monitor and interact with the plant processes The processes are displayed and interacted with in graphical displays ABB Inc 2012b Display hierarchy is usually divided into two to five levels to show different amounts of detail In the first level 1s the overview of the respective plant section It is a main menu like screen where the operator can navigate into specific units In the unit screen the operator can see the process flow in a logical order that corresponds with the physical process environment This is the screen used
71. sed in the practical work of this thesis are examined The main language used in the ABB System 800xA at Freeport Cobalt Ltd is the Structured Text As explained in the introduction there is a second older DCS still in use the ABB Advant Advant was programmed entirely in a type of Function Block Diagram The reason for the switch of programming language into ST is the more universal structure of the language This allows individuals from wider educational backgrounds to be able to understand and program the system more efficiently The third language the Sequential Function Chart is used at Freeport Cobalt in digressive basis It is mainly used to group start stop field devices in a chain This language however is being replaced by the System 800xA s integrated Group Sequence function Section 4 2 3 which is very quick to use and easy to learn because it is specifically designed for group starts stops whereas the SFC can be used in many other sequential process operations Korpij rvi 2013 Table 1 Examples of basic language functions ABB Inc 2012e Assignment functions Boolean functions not and amp xor or gt Arithmetic functions expt mul div add sub mod abs Conditional functions if then else Iteration functions for while repeat 20 Further details of the three languages used and studied can be found in the next three subsections The main language used in this work was the Structured Tex
72. sh a button labeled T ytt refill in order to lower the SO tank pressure The button would lower the setpoints of the control loops P7306 and P7312 A program was then created for the automatic control loops setpoint drop In order for the PID controllers to take external setpoint commands external control mode would have to be set in both controllers Once the background to this program was resolved a flowchart seen in Graph 30 was created to clarify the event Button External set Set external mode Set low values Set normal values GRAPH 30 Flowchart describing the events in the automatic setpoint drop The program for this was created in ST language using a conditional statement IF As seen in the code below the statement is initiated by the condition that the DOC Digital Output Calculated sends out a signal This DOC in the same way as in the consumption measurement was created as a separate control module in the Control Builder and then placed as a button in the graphics screen 50 if IO DOC 502 T YTT Signal Value then IO 502 5 ili P7306 Set ExtAutol 1 10 50 s ili P7312 IN SetExtAutol 1 306 Arvo i 3 50 P 312 Arvo i 3 30 else IO 502 S5 ili P7306 In set ExtAutol 0 10 50 5 1110 7312 SetExtAutol 0 P 306 Arvo 6 30 P 312 Arvo i 6 10 end if IO 502 S ili P7306 1In ExtRefAutol P7306 Arvo IO 502 s ili 7 312
73. siis olla nestett tarpeeksi ennen kaynnistysta H25 pesuri toimintakuvaus docx Sivu 1 1 APPENDIX 8 Antomaatioryhm suljetaan typpi 502 s ili lle ja autolle H7308 RE stet n paineet pois typpilinjasta H7308 ja suljetaan r H7308 estem lisen S02 n sy tt mi tt minen pra S SI APPENDIX 9 t ytt painike painetaan T ytt ON tilaan pudottaa t m paineen s d n ja kaasauksen s t piirit P7312 ja P7306 alemmas arvoihin 3 3 bar ja 3 5 bar Painikkeen aktivointi asettaa my s s t piirit E1A tilaan mik li s t piirit on automaatilla Auto tai miss tahansa muussa tilassa Painikkeen asettaminen takaisin OFF tilaan ei kuitenkaan aseta takaisin saatopiirien edellist toimintatilaa vaan se asetetaan k sin T ytt OFF tilassa saatopiirien P7312 ja P7306 asetusarvot a rat arvoihin 6 1 bar ja 6 3 bar Sailidalueen kaasuhalytys Q7312 TORVI aktivoituu kun O7312 MIT saavuttaa H rajan 8 0 ppm Torvin saa my s kasitilaan S02 s5ailioa toimintakuvaus doo Sivu 1 1 APPENDIX 10 a ee IL L l LI I TL minsmeuy Uewase zog LS min eas IRERE FECIT oon Fwam ma Pee aava aen zu p09c aala aeey CS a IMMIIM LY page AH JB E 94 e eaezan A 80E AH lt m ES
74. t Function Block Diagram was also used in some extent This language was mainly used in the older ABB Advant DCS Paloranta M 2013 3 3 1 Function Block Diagram Function Block Diagram FBD is a high level graphical programming language in which the control functions are divided into a number of function blocks or functions connected by flow signals A function block may contain simple logical conditions timers or counters but they can also provide a complex control function to a subprocess in a machine or even an industrial plant ABB Inc 2012e FBD is very suitable for describing Boolean logic with associated timers counters and bistables Most programmable controllers have such function blocks predefined in standard libraries such as discussed in section 3 2 for direct use by the programmer In a Function Block Diagram editor the parameters of functions and function blocks are shown as pins on the boxes The assignment of values to parameters is shown by lines connecting the pins An example of a FBD program can be seen in Appendix 11 ABB Inc 2012e Graph 11 is an example of an up down counter with a negated Boolean signal to CU The block is used for counting up and counting down the value in output CV Integer data type 15 needed to present other values than 1 or 0 Boolean values The diagram on the right of the block is a timing diagram representing its function horizontal axis representing time ABB Inc 2
75. tart and stop order of the devices were defined for example P6109 was defined to be number 3 as seen on row 13 in Graph 19 The final parameters is the start and stop delays used for example to assure the device is properly operating before starting the next device In the case of the scrubber it was stated that the first device to be started was the cascade PID controller tagged Q6107 and F6111 as shown in Graph 24 in order to start adjusting the correct pH value of the cleansing solution Next would be the pump M6139 so that the showers would start spraying the gas about to be fed in to the scrubber The start condition for the pump M6139 was that the fluid level in the scrubber tank should be above 10 as to the interlock discussed in section 4 2 2 If the interlock was active the group start button would display that the device M6139 is not ready for start After the scrubber would be successfully operating the PID controller P6109 was initiated so the correct vacuum pressure in the gas flowline would be achieved Finally the pump M6138 would start to vacuum the gas to the scrubber 39 hx 21PES2 GR GroupStatusDisplay 2 124 21PES2 GR GroupStatusDisplay Sa Group Status Show filter Show only preselected consumers Show Preselection details Object Name Description Type Status Alarm Intik Control Mode Step 21PES2 GR H25 Pesuri ryhm k ynnistys GROUP Starting Centra
76. ted by a fieldbus to a controller Handling of the information received from field instruments is defined by the program code that is downloaded into the controller memory This way connection interrupts between the server and controller will not stop the process flow entirely Berge J 2002 The operator and engineering workstations are in the uppermost level of the system hierarchy The operator workstations are normally situated in the plant control rooms From these terminals the operators can monitor and control the information received from the process instruments The information is incorporated into process graphics which closely correspond to the actual field environment This makes an easy to use efficient HMI Human Machine Interface Engineers configure the system from the engineering workplaces with the help of supplier specific programming tools and software Festo Didactic GmbH amp Co 1997 3 1 System architecture The system architecture specifies the relations of the different parts of the automation system In Graph 2 the composition of the system is portrayed in a tree like structure In the roots and top are the terminal devices which do not share further connections than the one In this case they are the field instruments actuators motors and computer terminals In traditional I O wiring each device has its own physical wiring connection to the system ports I O modules are arranged in a cluster and the info
77. uld occur explicit documentation of process devices would significantly speed up the maintenance work and accuracy Once the devices and their data types were successfully defined programming work was started first from the H2S desulphurization system First the operation of the system was studied and internalized In the study it was concluded that several safety and operability 22 features were lacking in the existing code There was no documentation available in the process graphics display to explain interlocks or other system functions Furthermore an interlock for the pump labeled M6139 was missing it was possible to start the pump even without necessary fluid level in the tank This would effectively cause the pump to break down These problems were resolved by adding a group sequence start to the system that prevents unsafe starting conditions The lacking documents were also created and made available for access directly from the process graphics screen The programming of the SO distribution tank was started in the same way as the H2S desulphurization system Similar deficiencies were discovered no documentation and inadequate interlocking and code The process graphics display was also completely redesigned for better interpretation of the system In the filling operation of the tank the pressure had to be lowered in order to get a higher pressure in the filling truck as in the SO tank For this purpose a button was prog
78. y 5 AUTOMATION OF SULFUR DIOXIDE DISTRIBUTION TANK 5 1 Operation principle 5 1 1 Instrumentation 5 1 2 Control loops 5 2 Practical programming phases N 11 12 13 14 14 14 16 17 18 19 20 21 22 23 24 25 26 27 31 33 35 36 37 39 40 40 41 42 43 5 2 1 Process graphics display 5 2 2 Interlocks 5 2 2 Calculated consumption measurement 5 2 3 Automatic control loop setpoint drop 5 3 Summary 6 CONCLUSIONS REFERENCES GRAPHS GRAPH 1 Process chart of Freeport Cobalt Ltd GRAPH 2 Example DCS system architecture GRAPH 3 Comparison of instrument connection setups GRAPH 4 Example of remote client access GRAPH 5 Simple controller rack setup GRAPH 6 Process graphics display GRAPH 7 Physical view of a full redundant network GRAPH 8 PI Control loop faceplate GRAPH 9 Engineering Workplace screen GRAPH 10 Liuotto project in Control Builder GRAPH 11 Example of a CTUD counter block GRAPH 12 A sequence structure GRAPH 13 A bioscrubber system for removal of H2S GRAPH 14 Indoor view of the desulphurization system GRAPH 15 P6109 closed control loop GRAPH 16 Q6107 and F6111 cascade control GRAPH 17 Example pole zero plot GRAPH 18 Steps for building a project in ABB 800xA GRAPH 19 Control module parameters of PID controller Q6107 GRAPH 20 A controller rack with several CI modules connected GRAPH 21 An I O cluster with redundant fieldbus slave units GRAPH 22 Configuration of H2S d
79. ystem other designers drew and documented the instrument I O connections in circuit diagrams which were used to look up the hardware setup An example of one these circuits can be found in Appendix 5 Once elucidated to which I O port each instrument will be connected each port of the I O modules were configured with the appropriate variables and their properties The variables are written in the following way application reference data type reference data type device tag signal type For example App 2 10 AIS T6113 MIT Signal 4 2 1 Process graphics display The code would be almost useless without the process graphics whereby the operators can interact with the desulphurization system The creation of the process graphics was started by creating a new aspect in the engineering workplace Section 3 2 3 Graph 9 Even though the graphic aspect is situated on the aspect server Section 3 1 2 the same way as other graphics the unfinished graphics did not display to the operators because there was 34 no way to navigate to the created aspect from the operator environment Section 3 2 2 The link was created when it was time to introduce the finished system Configuring of the graphics was done with the Graphics Builder Section 3 2 5 The first step was to create the dynamic graphic elements of the system devices This was done by browsing the elements in the Element Explorer inside the Graphics Builder The Element Explorer is directly

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