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INST 262 (DCS and Fieldbus), section 1 Lab Automatically

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1. ve paor 108 P104 105 NEUTRALIZER 2 AMMONIUM NITRATE PUMP SCRUBBER RECIRCULATION PUMP SCRUBBER RECIRCULATION PUMP nTric ACID METERING PUMP oo Dia 9 8 Seva 20 GPM 80 1800 GPM 25 F 1500 GPM 225 F 2AGPMO 70 F DP Atmosprere Rated read 30 PSI Rated head 10 PSI Rated head 10 PSI Farsa ead 58 PSI aor ae water Dw 10537 A 7 aya T L en rN aj gt 4 aye ED WIS q re zj Ni ad supp i Dwa 12051 1 i G z pa Ga T EA 5 a ESNE ad X k 1 a 0827 Lt 4 3 avy N R Ke La EI me beeen D i a i AA i fry Gi i oi AR t 2 I g i 30 PSI steam ree T t i TRY N Dwg 18820 GH H aye Hh A aie i pan CY AN a z i O f p a j A EN wel H s f G a i 1 gt lt i f suo wesi Bm 10385 tt tt y wk i 4 9 DpH J 4 1H Paor Poz P08 Paoa Pos 61 A very useful feature of the DeltaV Control Studio application is being able to switch the view to online mode and watching real time numerical data appear on the interconnecting lines between function blocks When you use the Control Studi
2. e Once you have calculated the gain of this loop controller calculate its proportional band value as well e Build a computer spreadsheet program to model the behavior of the proportional controller in this scenario You will know you are successful when it is able to duplicate any Output value shown on the trend graph at any particular point in time corresponding to the PV and SP values at that same point in time e What would this trend look like if the controller were left in manual mode instead of automatic mode file i00715 48 Question 31 Shown here is the faceplate of a digital electronic single loop process controller State your best guesses as to the functions of all buttons on this controller In particular elaborate on the difference between Auto and Manual modes and which parameters the arrow buttons affect Also describe what steps an operator would have to take to switch this controller from automatic to manual modes and manually change the output signal going to the control valve and describe a practical situation where the operator might be inclined to do such a thing file 102373 Question 32 In order to explore different process characteristics it is useful to have access to loop simulation software you can run on your own personal computer A loop simulation program mimics the behavior of a real process allowing you to make tuning changes to a PID controller and see the results in a
3. file 103294 70 Question 87 This level control system is supposed to maintain a constant liquid level inside the knockout drum preventing liquid from entering the compressor as well as gas from entering the scavenging pump Yet for some reason liquid did manage to enter the compressor causing the compressor to suffer major damage and leading to a complete shut down of the unit Vapor discharge Level controller Vapor liquid SP PV inlet Vacuum gauge Air to open valve Air supply Pressure transmitter Liquid discharge to scavenging pump A trend recording of liquid level and control valve position captured before the explosion holds the only clue as to why this happened Examine it to see if you can determine the source of the trouble 100 95 90 85 80 Ti 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 Time file 102117 71 Question 88 One of the pollutants generated by high temperature combustion processes is NO oxides of nitrogen NO forms at high temperatures when nitrogen and oxygen gases in the combustion air combine to form nitrogen oxygen molecules These molecules are considered a pollutant because they form nitric acid upon emission to the atmosphere and they also contribute to the formation of smog A common method of mitigating NO emissions is to recirculate exhaust gas into the intake of the combustion system Doing so reduces combustion temper
4. Answer 12 The syrup s sugar concentration will eventually become excessive as the analytical controller AC attempts to maintain setpoint 99 Answer 13 Evaporator LIC exchanger Concentrated syrup out return to boiler Liquid pump Syrup in Reverse The analytical controller AC is reverse acting in order to close off the steam valve if the sugar concentration of the syrup increases The level indicating controller LIC is direct acting in order to open up the discharge valve if the evaporator level increases The pressure indicating controller PIC is reverse acting in order to open up the compressor recycle valve if the pressure inside the evaporator decreases i e if the vacuum becomes too strong 100 Answer 14 This controller needs to be reverse acting Setpoint Reverse acting 1 SS Sa Ultrasonic Influent iter Filtering media Effluent This re drawing of the control system uses an opamp symbol in place of the ISA standard circle used to represent a loop controller Setpoint a Influent 4 Ultrasonic LIR H Filter Filtering media Effluent e A sudden increase in effluent flow rate clean water demand controller output increases e Level transmitter fails high indicating 100 full water level controller output decreases e Control valve actuator fails driving valve fully open ignoring controller signal controll
5. ES 120 VAC AS 20 PSI Breaker 4 Valve 15 Panel L2 Column 8 Tag Description Manufacturer Model Input range _ Output range Notes e a a eS Sa TT 205 Temperature vansmiter_ Rosemount 444 0 1500 F 420ma Upscale burnout ronal Resi vba ff asa a TIC 205 Controller Siemens PAC 353 Tv 205 Controlvalve Fisher 3 15 PSI 0 100 Failclosed ae7 013Uu09 dooj e 8uls e Suisn ureiseiq dooyT ojdures 6 Loop Diagram Blue team pressure loop Revised by Duncan D V Field process area Field panel JB 25 DCS cabinet 4 TB 52 TB 80 Red Red Red Red 1 11 Cable PT 73 Cable 4 Pr 1 BIk Bik BIk Blk Tube PV 73 TB 52 TB 80 Red Red Red Red 15 29 Cable 4 Pr 8 Blk Blk Blk AS 20 PSI Tag Description Manufacturer Model Input range Output range Notes PT 73 Pressure transmitter Rosemount 3051CD o 50PsI 420mA PY 73 VP transducer Fisher 846 amp 20ma 3i5Psi O ee a9 013009 SOq Sutsn weaBerq dooyT ajdureg v6 Loop Diagram Sludge tank level control Revised by Leaky Tube LT 24a Tube LT 24b f Supply A S 21 PSI Tube LV 24 Tube LV 24 Description Manufacturer _Input range Output range Notes Level transmitter Foxboro 25 150 HO 3i5psi ss Controller Foxboro 130 315Psi_ 3isPsi i O aeT 013U09 s1yeuInNeud SuIsn wreise1q dooyT sjdureg G6 Loop Diagram Unit feed flow control Revised by A Bradley Date April
6. choosing a process to build There are a number of process types to choose from when selecting the one you will build with your team The only non negotiable limitations is that the process must be safe legal and possible to complete in the time allotted for this lab What follows are some examples Air pressure control Tp From compressed air supply 30 PSI Alternatively let the supply air be Pressure manually controlled and the pressure vessel controller modulate the vent valve Vent Vp From compressed air supply 30 PSI Muffin fans like those used for cooling personal computers work surprisingly well as turbines and tachogenerators A smart temperature transmitter configured for millivolt signal input works well as a speed transmitter combined with a voltage divider to reduce the tach s output signal Vent down to a millivolt range 76 Water level control Fountain style water pumps work well for this purpose so long as the total pumping height head is not too great Alternatively let the in flow be manually controlled and the level controller modulate the drain valve Water flow control Fountain style water pumps work well for this purpose so long as the total pumping height head is not too great Simple venturi tubes may be fabricated using bell reducers and straight pipe sections in either plastic or metal Alternatively let the venturi flow be manually cont
7. optimum P I and D settings you find for your process for future reference Compare the optimum PID tuning parameter values you arrived at compared to those of your classmates Suggestions for Socratic discussion e How do the P I and D settings when all used together to achieve optimum control compare to the P setting by itself found to yield optimum proportional only control or the P and I settings found to yield optimum PI control or the P and D settings found to yield optimum PD control file 104309 43 Question 28 This temperature control system has a problem The process temperature is running above setpoint significantly the setpoint is 850 F and the temperature as indicated by TIC 205 is 934 F and showing no signs of cooling off over time Loop Diagram Furnace temperature control Revised by Mason Neilan Date April 1 2002 p Field panel Control room panel rocess area JB 12 CP 4 4 TB 15 TB 11 t eec e ae a ee S 205 E A a Seg a le POS Snr aias erens ee Red 2 L298 J Blk Blk 4 Blu Blu 2 BIKS EY Net tine 7 20 TIC Red TB 15 TB 11 1 tia Roi 18 4 Red Red Wht Ofg Wht Org Red ek Blk TY N Raas se esp see a a E o Sheer osrse Hips HH 205b Cable TY P05b Cable 3 Pr 2 Cable TY 205b Wht Tupe Pie Spiel Bk L8 Tog fo org L4 Tete Nis E
8. Answer 8 One potential cause is digester R 101 running too cold cooling off the contents of the second digester 97 Answer 9 A simple on off control system will apply full power to the heating element if the temperature is less than the setpoint and will completely shut off power to the heating element if the temperature is greater than the setpoint The result is a temperature graph that oscillates around the setpoint value over time Setpoint 945 F Temperature Time gt As you can see the temperature can never settle at any one temperature since the control action is all or nothing and changes based on a simple greater than or less than relationship between the process variable and the setpoint This is an example of a closed loop control system The control loop may be represented in the ladder logic schematic by means of causal arrows Control circuit diagram Element 98 Answer 10 Upper setpoint 350 F gt Lower setpoint 340 F gt Temperature Time gt Answer 11 The human operator plays the part of a reverse acting controller because the valve action must be opposite of any changes in process variable For example if the water temperature increases then the operator should move the control valve further closed e PV water temperature e SP ideal target water temperature in operator s mind e MV Fuel gas control valve position
9. Question 51 Question 52 Question 53 Question 54 Question 55 Question 56 Question 57 Question 58 Question 59 Question 60 Question 61 Read and outline the Distributed Control Systems DCS subsection of the Digital PID Controllers section of the Closed Loop Control chapter in your Lessons In Industrial Instrumentation textbook Note the page numbers where important illustrations photographs equations tables and other relevant details are found Prepare to thoughtfully discuss with your instructor and classmates the concepts and examples explored in this reading file 100813 57 Question 62 Search through Chapter 1 DeltaV System Overview of the Getting Started with your DeltaV Digital Automation System manual document D800002X122 March 2006 to answer the following questions Based on the simple network diagram shown on page 1 1 what type of digital network connects the PC workstation s to the DCS controller What is the System Identifier in a DeltaV system and what purpose does it serve Several software applications find frequent use in the maintenance and operation of a DeltaV control system DeltaV Explorer DeltaV Operate Run DeltaV Operate Configure Control Studio and DeltaV Books Online Identify what each of these software tools does Suggestions for Socratic discussion e A hallmark of Distributed Control Systems
10. Red team your loop number could be 2 Common mistakes e Neglecting to consult the manufacturer s documentation for field instruments e g how to wire them how to calibrate them e Mounting the field instrument s in awkward positions making it difficult to reach connection terminals or to remove covers when installed e Improper pipe tube fitting installation e g trying to thread tube fittings into pipe fittings and vice versa e Failing to tug on each and every wire where it terminates to ensure a mechanically sound connection e Students working on portions of the system in isolation not sharing with their teammates what they did and how It is important that the whole team learns all aspects of their system Building a functioning process complete with instrumentation for control typically takes one or two sessions 3 hours each if all components are readily available and the team is working efficiently 82 Lab Exercise documenting the system Each student must sketch their own loop diagram and their own P amp ID for their team s system following proper ISA conventions The P amp ID documents the flow of fluid and materials in your process plus the general control strategy The loop diagram documents all wiring and tube connections between instruments Although the two diagrams reinforce one another and might possibly be combined into one the industry standard is to use two separate diagrams Sample lo
11. eliminate confusing details add details to eliminate unknowns consider simple limiting cases apply an analogy Often you can add or remove components in a malfunctioning system to simplify it as well and better identify the nature and location of the problem Work backward from a hypothetical solution to a new set of given conditions How to create more time for study Kill your television and video games Seriously these are incredible wastes of time Eliminate distractions e g cell phone internet socializing in your place and time of study Use your in between time productively Don t leave campus for lunch Arrive to school early If you finish your assigned work early begin studying the next day s material Above all cultivate persistence Persistent effort is necessary to master anything non trivial The keys to persistence are 1 having the desire to achieve that mastery and 2 realizing challenges are normal and not an indication of something gone wrong A common error is to equate easy with effective students often believe learning should be easy if everything is done right The truth is that mastery never comes easy file question0O 19 Creative Commons License This worksheet is licensed under the Creative Commons Attribution License version 1 0 To view a copy of this license visit http creativecommons org licenses by 1 0 or send a letter to Creative Commons 559 Nathan Abbott Wa
12. file 103197 74 Question 91 Lab Exercise Your task is to build document and successfully operate a process controlled by a recording PID controller Several alternative process types exist and are documented in subsequent pages The working process you build will be used in future lab exercises this quarter to meet other learning objectives which means you will not disassemble this project at the completion of these lab objectives as you normally would The following table of objectives show what you and your team must complete within the scheduled time for this lab exercise Note how some of these objectives are individual while others are for the team as a whole Objective completion table Performance objective Grading 1 2 3 4 Team Choose process to build mastery Team meeting and prototype sketch mastery Circuit design challenge mastery A n Final loop diagram and system inspection mastery re Process and Instrument Diagram P amp ID mastery StS Trend graph displays PV and Output mastery Process exhibits good control behavior mastery PV alarm s defined and enabled mastery Lab question Instrument connections proportional gt Lab question Commissioning proportional AE Lab question Mental math proportional ea Lab question Diagnostics proportional a The only proportional scoring in this activity are the lab questions which are answer
13. save anything which will alter the configuration of the DCS just explore and observe e Note where the controller s direction of action i e direct or reverse action is selected in the PID function block How does one determine the correct direction of control action for any specific process e Immediately following the instruction on how to set controller s direction of action i e direct or reverse action this exercise specifies how to set a similar parameter in the IO_OPTS collection of parameters called Increase to Close This is used when the control valve happens to be air to close fail open to make the controller faceplate s output bargraph match the valve stem position so that a displayed output of 0 represents a shut valve and a displayed output of 100 represents a wide open valve Explain why this parameter is an important one to set in processes where the control valve is air to close One way of explaining the importance of this parameter is to describe what would happen if it were not set correctly for a particular control loop e Compare the setting of the process variable s engineering units to the MINSCALE and MAXSCALE parameters of the AI function block in a Siemens 353 loop controller How are these tasks similar and how are they different file 100814 Question 65 Read Exercise 9 Downloading the Modules in Chapter 4 Creating and Downloading the Control Str
14. 8 pints pt 128 fluid ounces fl oz 3 7854 liters 1 1 milliliter ml 1 cubic centimeter cm Conversion equivalencies for velocity 1 mile per hour mi h 88 feet per minute ft m 1 46667 feet per second ft s 1 60934 kilometer per hour km h 0 44704 meter per second m s 0 868976 knot knot international Conversion equivalencies for mass 1 pound Ibm 0 45359 kilogram kg 0 031081 slugs Conversion equivalencies for force 1 pound force lbf 4 44822 newton N Conversion equivalencies for area 1 acre 43560 square feet ft 4840 square yards yd 4046 86 square meters m Conversion equivalencies for common pressure units either all gauge or all absolute 1 pound per square inch PSI 2 03602 inches of mercury in Hg 27 6799 inches of water in W C 6 894757 kilo pascals kPa 0 06894757 bar 1 bar 100 kilo pascals kPa 14 504 pounds per square inch PSI Conversion equivalencies for absolute pressure units only 1 atmosphere Atm 14 7 pounds per square inch absolute PSIA 101 325 kilo pascals absolute kPaA 1 01325 bar bar 760 millimeters of mercury absolute mmHgA 760 torr torr Conversion equivalencies for energy or work 1 british thermal unit Btu International Table 251 996 calories cal International Table 1055 06 joules J 1055 06 watt seconds W s 0 293071 watt hour W hr 1 05506 x 101 ergs erg
15. DT 190 F 125 PSI 360 F Each bed 10 of 1 pall rings P201 EDH Slope x a aore 5 Deg sean gt am 1 T H ag 16 eis are s a X G i Haj a 7 D A e AD oa ar E s A A z Fa To ncnerator w we oad f Dp 13300 EB _ 6a x ere YY gt Dog soes a a a M Dwg 13322 uu SV in X se O DE X e Naa vo p4 nu aa goo ws ELA x X AH NBT Y Xe T ms i D a D N 5 aw J To i afl a att A A ee O E T Se wy lt ii amp aa aN N R IE ceang vaer D4 eo a U cy sid J P101 4 see Suppose the last instrument technician to calibrate the steam flow transmitter FT 28 made a mistake and the transmitter consistently reads 1 2 pound per minute more steam flow than there actually is going through the pipe For example if the actual steam flow is 6 9 poun
16. INST 251 5 cr PID Control INST 252 4 cr Loop Tuning CHEM amp 161 5 cr Jan Winter quarter Mar Chemistry INST 205 1 cr Job Prep Graduation Graduation Graduation Graduation INST 250 5 cr Final Control Elements INST 251 5 cr PID Control INST 252 4 cr Loop Tuning CHEM amp 161 5 cr Chemistry Mar Jan Winter quarter INST 206 1 cr Job Prep Il INST 250 5 cr Final Control Elements INST 251 5 cr PID Control INST 252 4 cr Loop Tuning CHEM amp 161 5 cr Mar Chemistry file sequence 11 General tool and supply list Wrenches e Combination box and open end wrench set 1 4 to 3 4 the most important wrench sizes are 7 16 1 2 9 16 and 5 8 get these immediately Adjustable wrench 6 handle sometimes called Crescent wrench Hex wrench Allen wrench set fractional 1 16 to 3 8 Optional Hex wrench Allen wrench set metric 1 5 mm to 10 mm Optional Miniature combination wrench set 3 32 to 1 4 sometimes called an ignition wrench set Note when turning any threaded fastener one should choose a tool engaging the maximum amount of surface area on the fastener s head in order to reduce stress on that fastener e g Using box end wrenches instead of adjustable wrenches usin
17. found on the BTC campus Y network drive A printed copy is posted in the Instrumentation classroom Locate industry documents assigned for reading use the Instrumentation Reference provided by your instructor on CD ROM and on the BTC campus Y network drive There you will find a file named 00_index_OPEN_THIS FILE html1 readable with any internet browser Click on the Quick Start Links to access assigned reading documents organized per course in the order they are assigned Study for the exams Mastery exams assess specific skills critically important to your success listed near the top of the front page of each course worksheet for your review Familiarize yourself with this list and pay close attention when those topics appear in homework and practice problems Proportional exams feature problems you haven t seen before that are solvable using general principles learned throughout the current and previous courses for which the only adequate preparation is independent problem solving practice every day Answer the feedback questions practice exams in each course section to hone your problem solving skills as these are similar in scope and complexity to proportional exams Answer these feedback independently i e no help from classmates in order to most accurately assess your readiness Calculate course grades download the Course Grading Spreadsheet grades_template xlsx from the Socratic Instrumentation website or
18. monitors the sugar concentration of the syrup and adjusts steam flow to the heat exchanger accordingly Steam supply Vapor compressor Water vapor out Evaporator exchanger Concentrated syrup out Condensate return to boiler Liquid pump Syrup in Suppose the syrup analyzer AT suffers a sudden calibration problem causing it to register too low telling the analytical controller that the sugar concentration of the syrup is less than it actually is Describe in detail the effect this calibration error will have on the performance of the analytical control system Suggestions for Socratic discussion e What economic effect will this mis calibration have on the process In other words does the process become more or less profitable as a result of this change e Suppose someone shuts the manual block valve on the steam line just a little bit so that it is about 80 open instead of 100 open How will this process change affect the control systems in this process file 102936 35 Question 13 A helpful strategy for qualitatively analyzing control systems is to mark the inputs of all loop controller bubbles with either or labels to denote the direction of each controller s action This is the same symbology used to mark the inputs of an operational amplifier where represents the noninverting input and represents the inverting input The following illustra
19. DCSs is hardware redundancy Identify specific redundant features of the Emerson DeltaV DCS e Access a DeltaV workstation PC and try opening each of the software applications listed exploring the features of each Do not download or save anything which will alter the configuration of the DCS just explore and observe file 100811 Question 63 Read Exercise 5 Creating a New Module LI 101 from Scratch in Chapter 4 Creating and Downloading the Control Strategy of the Getting Started with your DeltaV Digital Automation System manual document D800002X122 March 2006 and answer the following questions Which function block type is used in the LI 101 module and what does it do The output of the main function block in this module is wired to another object called an Output Connector What does an output connector do in the DeltaV system One of the configuration steps described has you add History Collection to the function block What exactly does this feature do After this module s function block has been wired to the Output Connector there are a few final steps required to finish the module Identify these steps and explain their purpose Suggestions for Socratic discussion e Access a DeltaV workstation PC and try opening a module using Control Studio Find some of the AI block parameters and options discussed in this exercise Do not download or
20. RTU Distributed Control System DCS you choose the appropriate I O module Emerson DeltaV with M series I O Emerson DeltaV with S series I O Honeywell Experion with 2MLF series I O e Programmable Logic Controller PLC you choose the appropriate I O module Siemens 7 300 Rockwell ControlLogix catalog number 1756 Rockwell CompactLogix catalog number 1769 Uae ae er ee R 4 20 mA Final Control Element options e Pneumatic control valve positioners Fisher 3582i positioner Fisher DVC6000 positioner Electrically actuated valves MOV Limitorque actuator with Modutronic 20 II controller Rotork AQ with Folomatic controller e AC motor drives VFD Rockwell PowerFlex 4 Automation Direct GS1 Study reference the Analog Electronic Instrumentation chapter of Lessons In Industrial Instrumentation particularly the section on HART Note a very effective problem solving strategy for determining how to connect different components together to create a working 4 20 mA current loop is to first identify whether each component acts as a source or a load in that loop circuit Then label voltage polarities and directions of current accordingly Knowing which way current must flow through each component and which polarity each voltage must have is key to ensuring the inter component connections are correct 81 Lab Exercise building the system 3 The Instrumen
21. Socratic discussion e Suppose you wished to change the connection path between two function blocks in a program Demonstrate how to do this e Suppose you wished to take the factory configured option program 101 and add a discrete output block then connect that block to the alarm block so that an external alarm light could be controlled by the alarm settings in the controller Demonstrate how to do this e Identify some of the different Factory Configured Options FCOs available to you e In section 10 1 5 a clever way is shown to change the upper range value of the AIN function block from 100 to 500 Instead of simply turning the pulser knob to increment 100 to 500 some decimal point shifting is used Explain how this works e Section 3 2 12 describes the meaning of five different priority levels for alarms in the ALARM function block Explain these priority levels in your own words e In section 10 1 8 describes one of the quick set parameters as POWER UP SETPOINT Explain what this parameter is useful for citing a practical application if possible file 100808 52 Question 42 Examine the Siemens Moore 353 program for pulse width modulation contained on your Instrumentation Reference showing a function block program for equipping the 353 controller with a PWM output signal modulated on off rather than an analog 4 20 mA output signal then answer the following questions Identify those function blocks w
22. a 0 00392 TT 37 Smart temp transmitter Rosemount 3244 100 250 F 4 20 mA Direct action TIC 37 DCS controller Honeywell PM Reverse action TY 37 I P transducer Fisher 546 4 20 mA 3 15 PSI Direct action TV 37 Steam control valve Fisher Easy E 3 15 PSI Air to open Choose one e Broken wire connection at TB12 11 e Short in cable 20 Resistor fails open in analog input field termination FTA AI e Sudden influx of cold fluid into reactor Sudden increase in steam supply pressure and temperature Determine these four system responses e Process temperature response over time e Operator indication of process temperature over time e Controller output over time e Steam flow through control valve over time file 102450 65 Question 82 According to the operator this pressure control system is not regulating filter water pressure correctly The controller faceplate indicates the pressure holding at setpoint 110 PSI but pressure indicated by a pressure gauge on the outlet pipe of the filter shows substantially less pressure 85 PSI Water in from pump Air supply Pressure gauge Controller Water out to points of use Air to open i i 1 i i i 1 i i j I I 1 1 i valve i I i i i i j j i I i i i 4 i I i I 0 to 150 PSI Pressure transmitter Water out back to sump KEER R ee A E O A E a E E E Your first test is to mea
23. basic concepts so valuable class time isn t wasted transmitting bare facts and also to foster the independent research ability necessary for self directed learning in your career Classroom sessions a combination of Socratic discussion short lectures small group problem solving and hands on demonstrations experiments review and illuminate concepts covered in the preparatory questions The purpose of this is to develop problem solving skills strengthen conceptual understanding and practice both quantitative and qualitative analysis techniques Lab activities an emphasis on constructing and documenting working projects real instrumentation and control systems to illuminate theoretical knowledge with practical contexts Special projects off campus or in different areas of campus e g BTC s Fish Hatchery are encouraged Hands on troubleshooting exercises build diagnostic skills Feedback questions sets of practice problems at the end of each course section challenge your knowledge and problem solving ability in current as as well as first year Electronics subjects These are optional assignments counting neither for nor against your grade Their purpose is to provide you and your instructor with direct feedback on what you have learned Tours and guest speakers quarterly tours of local industry and guest speakers on technical topics add breadth and additional context to the learning experience STUDENT ASSIGNMENTS REQUIREMENTS All ass
24. by passing comparable quizzes afterward or by having your preparatory work reading outlines work done answering questions thoroughly reviewed prior to the absence Absence on a scheduled exam day will result in a 0 score for the proportional exam unless you provide documented evidence of an unavoidable emergency If you fail a mastery exam you must re take a different version of that mastery exam on a different day Multiple re tries are allowed on a different version of the exam each re try There is no penalty levied on your course grade for re taking mastery exams but failure to successfully pass a mastery exam by the due date i e by the date of the nezt exam in the course sequence will result in a failing grade F for the course If any other mastery objectives are not completed by their specified deadlines your overall grade for the course will be capped at 70 C grade and you will have one more school day to complete the unfinished objectives Failure to complete those mastery objectives by the end of that extra day except in the case of documented unavoidable emergencies will result in a failing grade F for the course Lab questions are assessed by individual questioning at any date after the respective lab objective mastery has been completed by your team These questions serve to guide your completion of each lab exercise and confirm participation of each individual student Grading is as follows full credi
25. controller Reverse acting controller SP SP Output Output PV PV Output PV SP Output SP PV 26 Example 5 Label the PV amp SP amplifier inputs for the correct controller action Water in from pump Air supply Controller Transducer Water out back to sump SP to points of use i PV I i i Air to open valve i i Pressure transmitter Water out i I I i beer eee otee sees se eee eee Sse eee ce RAAH RARR AAA ARRA RANAN RA Example 6 Label the PV amp SP amplifier inputs for the correct controller action Air supply Controller Transducer transmitter Air to open valve 27 Example 7 Label the PV amp SP amplifier inputs for the correct controller action Steam in Cold fluid in Air to open valve F Transducer Warm fluid out Steam out Thermocouple Controller Temperature SP transmitter Zsa Suggestions for Socratic discussion As always what is more important than arriving at the correct answer s is to develop a clear and logical reason for your correct answers Explain the problem solving technique s you used to determine correct controller action in each of these process control examples A powerful problem solving technique is performing a thought experiment where you mentally simulate the response of a system to some imagined set of conditions Describe a useful thought experiment for any of t
26. due to the heat of the vapors a make up system loop 35 must add water to maintain a constant liquid level at the bottom of the scrubber vessel vs vs SCRUBBER NEUTRALIZER 7 6 Da 20 8 Sidewa 10 4 Dia 9 8 Sidewal Stack height 14 6 DP Atmosphere DP Atmosphere or 270 F Pant P02 P10 P1048 105 MONIUM NITRATE PUMP 83 AMMONIUM NITRATE PUMP SCRUBBER RECIRCULATION PUMP SCRUBBER RECIRCULATION PUMP NITRIC ACID METERING PUMP 20 GPM 80 F 5GPM 80 F 1500 GPM 225 F 1500 GPM 225 F 24GPM 70 F 20 PS ated head 75 PSI sar am Rated head 80 PSI PSI Rated head 10 PSI Rated head 10 PSI Rated head 55 PSI ake up watar Dwg 10537 ai FN FA Ke Sy fe kes A etrgas Big 10927 a H Eas m9 aoa E i z ps an AA lt Pa AIR S Kz ene ALG HA at Mes PO a EEE He Sl ty i EN AN rt fee i i z X l i kz Suppose the last instrument technician
27. from the BTC campus Y network drive Enter your quiz scores test scores lab scores and attendance data into this Excel spreadsheet and it will calculate your course grade You may compare your calculated grades against your instructors records at any time Identify courses to register for read the Sequence page found in each worksheet Identify scholarship opportunities check your BTC email in box daily Identify job openings regularly monitor job search websites Set up informational interviews at workplaces you are interested in Participate in jobshadows and internships Apply to jobs long before graduation as some employers take months to respond Check your BTC email account daily because your instructor broadcast emails job postings to all students as employers submit them to BTC Impress employers sign the FERPA release form granting your instructors permission to share academic records then make sure your performance is worth sharing Document your project and problem solving experiences for reference during interviews Honor all your commitments Begin your career participate in jobshadows and internships while in school to gain experience and references Take the first Instrumentation job that pays the bills and give that employer at least two years of good work to pay them back for the investment they have made in you Employers look at delayed employment as well as short employment spans very negatively Failure to p
28. lifetime guarantees e g Sears Craftsman brand Check for BTC student discounts as well file tools 12 Methods of instruction This course develops self instructional and diagnostic skills by placing students in situations where they are required to research and think independently In all portions of the curriculum the goal is to avoid a passive learning environment favoring instead active engagement of the learner through reading reflection problem solving and experimental activities The curriculum may be roughly divided into two portions theory and practical Theory In the theory portion of each course students independently research subjects prior to entering the classroom for discussion This means working through all the day s assigned questions as completely as possible This usually requires a fair amount of technical reading and may also require setting up and running simple experiments At the start of the classroom session the instructor will check each student s preparation with a quiz Students then spend the rest of the classroom time working in groups and directly with the instructor to thoroughly answer all questions assigned for that day articulate problem solving strategies and to approach the questions from multiple perspectives To put it simply fact gathering happens outside of class and is the individual responsibility of each student so that class time may be devoted to the more complex tasks of cr
29. must give proper credit to myself as the original author and licensor Given that these worksheets will be continually made available on the internet for free download though few people will pay for what you are selling unless you have somehow added value Nothing in the License prohibits the application of a more restrictive license or no license at all to derivative works This means you can add your own content to that which I have made and then exercise full copyright restriction over the new derivative work choosing not to release your additions under the same free and open terms An example of where you might wish to do this is if you are a teacher who desires to add a detailed answer key for your own benefit but not to make this answer key available to anyone else e g students Note the text on this page is not a license It is simply a handy reference for understanding the Legal Code the full license it is a human readable expression of some of its key terms Think of it as the user friendly interface to the Legal Code beneath This simple explanation itself has no legal value and its contents do not appear in the actual license file license 20 Questions Question 1 Read and outline the Basic Feedback Control Principles section of the Closed Loop Control chapter in your Lessons In Industrial Instrumentation textbook Note the page numbers where important illustrations photographs equations table
30. required direction of valve operation to correct for an upset off setpoint condition is it possible to properly and confidently configure an automatic controller to do the same This is something every instrument professional needs to consider when designing and or commissioning a control system which way does the final control element need to go in order to stabilize the process variable if it deviates too high In the first example we would need to move the fuel gas valve further closed toward the shutoff position if ever the temperature got too high In the second example we would need to move the drain valve further open to correct for a too high liquid level in the vessel In the third example we would need to move the flow control valve further closed toward shutoff if ever the flow rate measured too high In the fourth example we would need to open the control valve further in order to reduce a too high oil temperature exiting the heat exchanger The rationale for this direction of valve motion is to increase the flow rate of the oil so that each molecule spends less time in the heat exchanger absorbing heat from steam and increasing in temperature Answer 30 Gain 0 5 and bias 30 Answer 31 e Displ button change display mode e Auto Man button toggle between automatic and manual modes Config button Enter the configuration menu Up T Button increase setpoint Down Butto
31. save anything which will alter the configuration of the DCS just explore and observe e Compare the setting of the process variable s engineering units to the MINSCALE and MAXSCALE parameters of the AI function block in a Siemens 353 loop controller How are these tasks similar and how are they different file 100812 58 Question 64 Read Exercise 6 Creating a PID Control Loop FIC 101 from Scratch in Chapter 4 Creating and Downloading the Control Strategy of the Getting Started with your DeltaV Digital Automation System manual document D800002X122 March 2006 and answer the following questions In this exercise the user is shown how to begin configuring a control module without starting from scratch as in Exercise 5 How is this done Although you will often find PID function blocks wired to analog input AI function blocks and analog output A0 function blocks to make a complete working loop module here in this exercise the PID function block stands alone In lieu of AI and AO function blocks to route the signals to and from real world I O channels how does this PID function block know where to get its PV input and where to send its MV output signals Suggestions for Socratic discussion e Access a DeltaV workstation PC and try opening a module using Control Studio Find some of the PID block parameters and options discussed in this exercise Do not download or
32. the controller s ability to manage variations in process load over time A controller s response to load changes will often differ from its response to setpoint changes You still want controller response that is reasonably fast without overshooting or undershooting too much and without undue cycling However you may have to find some compromise in tuning between good setpoint response and good load response How you decide that compromise depends on whether the controller really needs to respond mostly to setpoint changes e g the slave controller of a cascade loop or to load changes Step 9 Increase or decrease the control action aggressiveness according to the results of Step 8 Step 10 Repeat steps 8 and 9 for P I and D one at a time in that order In other words tune the controller first to act as a P only controller then add integral PI control then derivative PID each as needed Caveats The procedure described here is very crude and should only be applied as a student s first foray into PID tuning on a safe demonstration process It assumes that the process responds predominantly to proportional P only action which may not be true for some processes It also gives no specific advice for tuning based on the results of step 3 which is the mark of an experienced PID tuner With study practice and time you will learn what types of processes respond best to P I and D actions and then you will be abl
33. the valve basane further open or further closed 10 50 mA i Temperature is too high Suggestions for Socratic discussion e Follow up question in which of these examples is the operator functioning as a direct action controller and in which of these examples is the operator functioning as a reverse action controller file 100109 47 Question 30 An indispensible tool for process operators and instrument technicians alike is the trend graph showing such control loop variables as PV SP and controller Output superimposed on the same time domain plot The following example shows the process variable setpoint and output for a proportional only controller as it responds to changes in a control loop s PV while the setpoint remains at a constant value of 40 100 95 90 85 80 T 70 65 60 55 50 Time gt Based on an examination of this trend graph determine the bias value of the controller and gain value of the controller as well as its direction of action direct or reverse A helpful analysis technique when relating trend graphs to controller equations is to sketch a vertical line on the graph to identify some particular point in time then identify the values of PV SP and Output at that point in time A proper equation for the controller will successfully predict the Output value from the PV and SP values at any point in time shown on the trend Suggestions for Socratic discussion
34. value for Output with the actual status of the final control element If there is good correspondence between the controller s Output display and the FCE s status then there probably isn t anything wrong with the output portion of the control loop e g FCE output signal wiring analog output of controller etc If the controller Output value differs from the FCE s state then something is definitely wrong here 4 Reacting Compare the process variable value with the final control element s state Is the process doing what you would expect it to If so the problem is most likely not within the process e g manual valves relief valves pumps compressors motors and other process equipment If however the process is not reacting the way you would expect it to given the final control element s state then something is definitely awry with the process itself 85 A crude closed loop PID tuning procedure Tuning a PID controller is something of an art and can be quite daunting to the novice What follows is a primitive oversimplified for some situations procedure you can apply to many processes Step 1 Understand the process you are trying to control If you do not have a fundamental grasp on the nature of the process you re controlling it is pointless even dangerous to change controller settings Here is a simple checklist to cover before touching the controller e What is the process variable and how is
35. 1 2013 Process area Field panel FP 25 Red rn g Fi Red Blu PS 1 fe eefe e 24 Hosan 120 VAC 3 N3 A 3 1762 IF4 analog input card Loop expansion slot 1 Red Red Blu ay PNY 2 jm caslervas o Pole aS A T IAS 20 PSI Located in main Blk Wht Grn control room ES 120 VAC pate From field analog output card expansion slot 2 panel disconnect Flow transmitter BUG ae ie HMI touch panel AutomationDirect C More Cd FV 18 Flow valve with positioner 20 haley cen eaTeaA UO paTTeysul JouorzIsod s1u01 DaT9 YIM OT SUN ureiserq dooyT ojdures file 100654 96 Answers Answer 1 Answer 2 Answer 3 Answer 4 A load is any variable in a process besides the manipulated variable that has influence over the process variable being controlled Note the following answers are not exhaustive In other words there may be more loads than what is listed here for each process e Example 1 ambient air temperature e Example 2 incoming flow rate e Example 3 upstream and downstream pressures e Example 4 steam flow rate steam temperature Answer 5 Partial answer Controller 1 needs to be reverse acting Controller 3 needs to be direct acting Controller 5 needs to be direct acting i e PV input is and SP input is Controller 7 needs to be reverse acting i e PV input is and SP input is Answer 6 Answer 7
36. 778 169 foot pound force ft lbf Conversion equivalencies for power 1 horsepower hp 550 ft lbf s 745 7 watts W 2544 43 british thermal units per hour Btu hr 0 0760181 boiler horsepower hp boiler Acceleration of gravity free fall Earth standard 9 806650 meters per second per second m s 32 1740 feet per second per second ft s 17 Physical constants Speed of light in a vacuum c 2 9979 x 108 meters per second m s 186 281 miles per second m s Avogadro s number N4 6 022 x 10 per mole mol Electronic charge e 1 602 x 1071 Coulomb C Boltzmann s constant k 1 38 x 107 3 Joules per Kelvin J K Stefan Boltzmann constant o 5 67 x 1078 Watts per square meter Kelvin W m K Molar gas constant R 8 314 Joules per mole Kelvin J mol K Properties of Water Freezing point at sea level 32 F 0 C Boiling point at sea level 212 F 100 C Density of water at 4 C 1000 kg m 1 g cm 1 kg liter 62 428 lb ft 1 94 slugs ft Specific heat of water at 14 C 1 00002 calories g C 1 BTU Ib F 4 1869 Joules g C Specific heat of ice 0 5 calories g C Specific heat of steam 0 48 calories g C Absolute viscosity of water at 20 C 1 0019 centipoise cp 0 0010019 Pascal seconds Pa s Surface tension of water in contact with air at 18 C 73 05 dynes cm pH of pure water at 25 C 7 0 pH scale 0 to 14 Properties of Dry Air at sea l
37. Desktop Process exercise Configure the controller as follows for proportional only control Control action reverse Gain 1 Proportional Band 100 Reset Integral minimum effect 100 minutes repeat 0 repeats minute Rate Derivative minimum effect 0 minutes Check to see that the controller is able to function in automatic mode adjusting motor speed as you adjust the setpoint value Now you are set to experiment with the effect of different gain values in the PID algorithm You may access the gain parameter by entering the controller s tuning function Try setting the gain value to a number significantly less than 1 then changing the setpoint SP value several times to observe the system s response If you have a data acquisition DAQ unit connected to measure controller PV and output signal values note the relationship between the two graphs plotted on the computer display following each setpoint change Now try setting the gain value to a number significantly greater than 1 changing the setpoint value again and again to observe the system s response Answer the following questions e Which gain settings result in the swiftest response from the motor e Which gain settings result in the most sluggish response from the motor e Are there any gain setting values that result in oscillation of motor speed e Do you notice any proportional only offset e Determine the op
38. INST 262 DCS and Fieldbus section 1 Lab Automatically controlled process Questions 91 and 92 completed objectives due by the end of day 5 section 2 Exam Day 5 of next section Specific objectives for the mastery exam e Electricity Review Calculate voltages currents powers and or resistances in a DC series parallel circuit e Identify proper controller action direct or reverse for a given process e Predict the response of a single loop control system to a component fault or process change e Identify specific instrument calibration errors zero span linearity hysteresis from data in an As Found table e Solve for a specified variable in an algebraic formula e Determine the possibility of suggested faults in a 4 20 mA loop circuit given measured values voltage current a schematic diagram and reported symptoms e INST231 Review Sketch proper wire connections for sourcing or sinking PLC I O points e INST240 Review Determine suitability of different level measuring technologies for a given process fluid type e INST251 Review Identify the graphed response of a controller as being either P I or D Recommended daily schedule Day 1 Theory session topic Feedback control Questions 1 through 20 answer questions 1 8 in preparation for discussion remainder for practice Day 2 Theory session topic PID control Questions 21 through 40 answer questions 21 28 in preparation for discussion remaind
39. S 120 VAC Breaker 4 AS 20 PSI Fuel Val 15 Panel L2 to furnace alve Column 8 Tag number Description Manufacturer Model Calibration Notes TE 205 Thermocouple Omega Type K Ungrounded tip TT 205 Temperature transmitter Rosemount 444 0 1500 F 4 20 mA TY 205a Resistor Vishay 250 Q TIC 205 Controller Siemens PAC 353 15V o 4500 F Reverse acting control TY 205b I P transducer Fisher 546 420MA 3 45 PSI TV 205 Control valve Fisher Easy E 3 15 PSI Fail closed The operator tells you the process was working just fine yesterday holding right at the setpoint value of 850 F Your first step is to examine the faceplate of the controller it is in automatic mode and the output is at a value of 5 Explain the rationale behind checking the controller s mode and output value How is this information helpful in troubleshooting the problem What would be your next step in troubleshooting this problem What might you do differently if you had seen the controller in a different mode or with its output at some different greater value Suggestions for Socratic discussion e How significant is the information that this process was working fine just yesterday Would it make any difference to your diagnosis if you had been told this process has never worked right e Suppose this system were functioning perfectly well and then something pinched Cable 3 Pair 2 and caused it to fail shorted Explain what would happen a
40. alve determine whether the level controller needs to be configured for direct action or reverse action and explain your reasoning Annotate the diagram with and symbols next to the PV and SP controller inputs to show more explicitly the relationships between the controller inputs and output Next determine the response of the controller to the following situations In other words determine what the controller s output signal will do when this water level control system is affected in the following ways e A sudden increase in effluent flow rate clean water demand e Level transmitter fails high indicating 100 full water level e Control valve actuator fails driving valve fully open ignoring controller signal Suggestions for Socratic discussion e Re draw the diagram for this water filter level control system replacing the controller circle with an op amp symbol triangle determining the and input assignments on the opamp for PV and SP e Explain why level control is important in a water filter such as this e What do the H and L symbols near the LIR represent file 102370 37 Question 15 There is a problem somewhere in this liquid flow control system The controller is in automatic mode with a setpoint of 65 yet the flow indicator and the flow controller both register 0 3 nearly zero flow A P amp ID of the loop appears here Explain how you w
41. apply these hours to any missed time this is not done automatically Students may donate unused sick time to whomever they specifically choose You must contact your instructor and lab team members immediately if you know you will be late or absent or must leave early Absence on an exam day will result in a zero score for that exam unless due to a documented emergency Time Management You are expected to budget and prioritize your time just as you will be on the job You will need to reserve enough time outside of school to complete homework and strategically apply your time during school hours toward limited resources e g lab equipment Frivolous activities e g games social networking internet surfing are unacceptable when work is unfinished Trips to the cafeteria for food or coffee smoke breaks etc must not interfere with team participation Independent Study This career is marked by continuous technological development and ongoing change which is why self directed learning is ultimately more important to your future success than specific knowledge To acquire and hone this skill all second year Instrumentation courses follow an inverted model where lecture is replaced by independent study and class time is devoted to addressing your questions and demonstrating your learning Most students require a minimum of 3 hours daily study time outside of school Arriving unprepared e g homework incomplete is unprofessio
42. arm fluid Steam out out Thermocouple Temperature transmitter 25 Example 4 Steam in Air to open ae Siena F ou 4 creak F Air Supply A concept familiar to students of electronics is the differential amplifier a device built to compare two input signals and generate an output signal proportional to that comparison The most common form of differential amplifier is the so called operational amplifier or opamp drawn as a triangle with two inputs labeled and to show the relative influence of each input signal on the output A process controller may be thought of as a kind of differential amplifier sensing the difference between two input signals the process variable and the setpoint and generating an output signal proportional to the difference between PV and SP to drive a final control element The following process control examples replace the controller symbol with an amplifier symbol Your task is to figure out appropriate labels for the amplifier s input terminals e g and Remember that a controller is defined as being direct acting if an increase in PV causes an increase in output and reverse acting if an increase in PV causes a decrease in output Following opamp labeling this means the PV input of a direct acting controller should bear a mark while the PV input of a reverse acting controller should bear a mark Direct acting
43. ass a drug test is an immediate disqualifier as is falsifying any information Criminal records may also be a problem file howto General Values and Expectations Success in this career requires professional integrity resourcefulness persistence close attention to detail and intellectual curiosity Poor judgment spells disaster in this career which is why employer background checks including social media and criminal records and drug testing are common The good news is that character and clear thinking are malleable traits unlike intelligence these qualities can be acquired and improved with effort This is what you are in school to do increase your human capital which is the sum of all knowledge skills and traits valuable in the marketplace Mastery You must master the fundamentals of your chosen profession Mastery assessments challenge you to demonstrate 100 competence with multiple opportunities to re try Failure to complete any mastery objective s by the deadline date caps your grade at a C Failure to complete by the end of the next school day results in a failing F grade Punctuality and Attendance You are expected to arrive on time and be on task all day just as you would for a job Each student has 12 hours of sick time per quarter applicable to absences not verifiably employment related school related weather related or required by law Each student must confer with the instructor to
44. at the alarm unit AAH AAL 41 and also where you would expect to measure voltage in the loop circuit and where you would expect to measure no voltage in the loop circuit The AAL would trip but not the AAH and we would expect to measure voltage between the wires of cable 52 but not between the wires of cable 30 e Ifa fire breaks out near the conduit through which cable 52 runs causing the conductors inside cable 52 to short together what will happen in this system Where would you expect to measure voltage in the loop circuit and where would you expect to measure no voltage in the loop circuit Where would you expect to measure current in the loop circuit and where would you expect to measure no current in the loop circuit The AAL would trip but not the AAH and we would expect to measure no voltage anywhere in the loop circuit However we would still have current at the terminals of the AIT 41 transmitter although no current to the right of the short Answer 45 Answer 46 104 Answer 47 Answer 48 Answer 49 Answer 50 Answer 51 Answer 52 Answer 53 Answer 54 Answer 55 Answer 56 Answer 57 Answer 58 Answer 59 Answer 60 Answer 61 Answer 62 Answer 63 Answer 64 Answer 65 Answer 66 Answer 67 Answer 68 Answer 69 Answer 70 Answer 71 Answer 72 Answer 73 105 Answer 74 Answe
45. ategy of the Getting Started with your DeltaV Digital Automation System manual document D800002X122 March 2006 and answer the following questions The final step in implementing control modules in the DeltaV system is to do a download Explain what this procedure accomplishes and what would happen if we forgot to do it An Important warning note is given on page 4 53 of this tutorial Explain in your own words what you need to be cautious about file 100816 59 Question 66 Search through Chapter 5 Creating Operator Pictures of the Getting Started with your DeltaV Digital Automation System manual document D800002X122 March 2006 to answer the following questions Identify a fast way to switch between the Run and Configure modes of DeltaV Operate This tutorial advises against creating a new picture file from scratch Instead what is the recommended method for creating a graphical screen for operators to use Describe the purpose of the DeltaV_Toolbox in Delta V Operate Configure mode and how this toolbox may be used to create graphic objects on the screen for operator displays Explain what a link is in DeltaV Operate Specifically what is a datalink and what might one be used for Explain what a parameter reference is in DeltaV Operate Explain what a dynamo is in DeltaV Operate Page 5 30 begins a discussion on Trend Links which is an
46. ature a critical variable in the production of NO Recirculation blower To induced draft blower Exhaust out From forced draft blower From fuel gas supply AN Fuel in The reduction in combustion temperature approximately relates to exhaust gas recirculation by the following formula _Ty T p a ee T Tw Where X Recirculation fraction between 0 and 1 unitless Tm Maximum theoretical flame temperature T Actual flame temperature Tw Exhaust gas temperature Algebraically manipulate this equation to solve for T then calculate the actual flame temperature given a maximum theoretical temperature of 3100 F an exhaust gas temperature of 480 F and a recirculation factor of 22 Also explain why we must have a recirculation blower installed at the location shown in the diagram rather than a simple recirculation valve file 101830 72 Question 89 Small relays often come packaged in clear rectangular plastic cases These so called ice cube relays have either eight or eleven pins protruding from the bottom allowing them to be plugged into a special socket for connection with wires in a circuit top views Relay socket 2121212 Relay Draw the necessary connecting wires between terminals in this circuit so that actuating the normally open pushbutton switch will energize the relay which will in turn supply electrical power to the motor The pushbutton switch should not ca
47. ay No student should consider the distance mode of learning a way to have more free time to themselves because they will actually spend more time engaged in the coursework than if they attend school on a regular schedule It exists merely for the sake of those who cannot attend during regular school hours as an alternative to course withdrawal file distance 15 Metric prefixes and conversion constants Metric prefixes Yotta 1074 Symbol Y Zeta 107 Symbol Z Exa 10 8 Symbol E Peta 10 Symbol P Tera 10 Symbol T Giga 10 Symbol G Mega 10 Symbol M Kilo 10 Symbol k Hecto 10 Symbol h Deca 10 Symbol da Deci 107 Symbol d Centi 107 Symbol c Milli 107 Symbol m Micro 1078 Symbol p Nano 107 Symbol n Pico 10 Symbol p Femto 1071 Symbol f Atto 107 8 Symbol a Zepto 107 Symbol z Yocto 10774 Symbol y METRIC PREFIX SCALE T G M k m u n p tera giga mega kilo none milli micro nano pico POE CTO OP Ao TOP MO OTe TOT 0S roS IOIO 1 054 hecto deca deci centi h da d c Conversion formulae for temperature F C 9 5 32 C F 32 5 9 R F 459 67 K C 273 15 Conversion equivalencies for distance 1 inch in 2 540000 centimeter cm 1 foot ft 12 inches in 1 yard yd 3 feet ft 1 mile mi 5280 feet ft 16 Conversion equivalencies for volume 1 gallon gal 231 0 cubic inches in 4 quarts qt
48. blems in a system using Ethernet to exchange process data between controllers e If you had the choice of connecting multiple Ethernet capable controllers together would you opt for an Ethernet switch or an Ethernet hub as the connecting node between controllers Explain your reasoning e Modbus is designed to employ master slave arbitration Ethernet is uses CSMA CD arbitration How is it possible for Modbus to work over an Ethernet connection if the two arbitration protocols are different file 100716 54 Question 44 This pH monitoring system triggers an alarm if the pH value of the process water in the neutralization tank drifts past either of two threshold trip values JB 104 Control room TB 56 E S 120 VAC Breaker 31 panel L2 Breaker 25 panel L4 Answer the following questions about this pH alarm system e If a wire breaks loose at TB56 4 creating an open fault in the loop circuit determine what will happen at the alarm unit AAH AAL 41 and also where you would expect to measure voltage in the loop circuit and where you would expect to measure no voltage in the loop circuit e If breaker 25 in panel L4 suddenly trips what will happen in this system Will an operator still be able to read the pH value of the water in the neutralization tank e Ifa fire breaks out near the conduit through which cable 52 runs causing the plastic insulation around the conductors of cable 52 to melt and consequently causin
49. block 10 1 6 Alarms This subsection shows you how to change the alarm values and priorities The instructions imply a connection between output and PV input such that you can simulate any PV signal desired simply by switching to manual mode and adjusting the output If your controller is connected to a working process I recommend running the controller in automatic mode and adjusting the setpoint to make the PV go to the desired value s 5l 10 1 7 Tag This subsection shows you how to change the tag name of the loop 10 1 8 Quick This subsection explores the Quick set feature to change certain parameters in any function block In this particular case the instructions guide you to configuring a ramping setpoint value 10 1 9 Tune This subsection explores the Tune feature to change P I and D tuning parameters and also to activate autotune If your controller is connected to a working process feel free to engage the autotune feature and see how well it does In my general experience a competent technician can always achieve more robust control through careful hand selection of tuning parameter than by relying on an autotune feature but go ahead and try it just for fun 10 1 10 View This subsection explores the View feature to monitor variables inside the controller This can be a very useful diagnostic tool especially when developing and debugging new function block programs Suggestions for
50. book by Ralph Dewey ISBN 10 1 880215 26 8 A pocket sized field reference on basic measurement and control Cad Standard CadStd or similar AutoCAD like drafting software useful for sketching loop and wiring diagrams Cad Standard is a simplified clone of AutoCAD and is freely available at http www cadstd com CAMPUS EMERGENCIES If an emergency arises your instructor may inform you of actions to follow You are responsible for knowing emergency evacuation routes from your classroom If police or university officials order you to evacuate do so calmly and assist those needing help You may receive emergency information alerts via the building enunciation system text message email or BTC s webpage http www btc ctc edu Facebook or Twitter Refer to the emergency flipchart in the lab room located on the main control panel for more information on specific types of emergencies ACCOMMODATIONS If you think you could benefit from classroom accommodations for a disability physical mental emotional or learning please contact our Accessibility Resources office Call 360 752 8345 email ar btc ctc edu or stop by the AR Office in the Admissions and Student Resource Center ASRC Room 106 College Services Building file INST262syllabus Sequence of second year Instrumentation courses Core Electronics 3 qtrs including MATH 141 Precalculus 1 Only if 4th quarter was Summer INST23x Offered 1 week o
51. controller s features and capabilities To do this exercise you will need access to a Siemens model 353 controller Feel free to use one of the panel mounted 353 controllers in the lab or one of the Desktop Process units or even a 353 controller taken from storage It is definitely a hands on activity 10 1 1 Connections and Power This subsection describes how to connect AC power to the controller and also how to connect the output to the PV input for the purposes of the subsequent tests Feel free to skip this second part especially if your controller is already connected to a real process Proceed through each of the subsections following the step by step instructions 10 1 2 Configuration This subsection refers you to another section of the manual instructing you to load Factory Configured Option number 101 FCO 101 10 1 3 Input Output This subsection shows you how to verify the Setpoint Output and Process Variable I O as configured in FCO 101 and points you to the diagram of FCO 101 to verify the connections of P S and V in the ODC function block 10 1 4 Auto Manual This subsection shows you how to test the Automatic and Manual modes 10 1 5 Modifying an FCO This subsection shows you how to make changes to the function blocks within FCO 101 The changes include e Adding a new function block to FCO 101 e Perusing parameters inside a function block e Changing MINSCALE and MAXSCALE parameters of the AIN1 function
52. ds per minute the transmitter outputs a current signal corresponding to 8 1 pounds per minute Describe in detail the effect this mis calibration will have on the performance of the steam flow control system Suggestions for Socratic discussion e Perform a thought experiment where you borrow a friend s car to drive not knowing the this car s speedometer reads faster than you are actually traveling What speed will you actually be driving as you attempt to obey the speed limit e How do you suppose this miscalibration will affect the performance of the sour water stripping unit e Would this miscalibration be evident to an operator looking at the faceplate graphic display of FIC 28 Why or why not e For those who have studied calibration errors would you characterize this error as a zero shift a span shift a non linearity or hysteresis e Explain why nearly every automatic control valve in this process is flanked by two block hand valves one upstream and one downstream and paralleled by a bypass hand valve file 102928 29 Question 7 In this process nitric acid and ammonia vapor are combined to form a chemical called ammonium nitrate a key ingredient in synthetic fertilizer The scrubber vessel V 5 uses a liquid spray to remove volatile chemical compounds from vapors before they exit out of an exhaust stack and into the atmosphere As water evaporates from this liquid solution
53. e from instructor This disk contains many tutorials and datasheets in PDF format to supplement your textbook s e Tool kit see detailed list e Simple scientific calculator non programmable non graphing no unit conversions no numeration system conversions TI 30Xa or TI 30XIIS recommended ADDITIONAL INSTRUCTIONAL RESOURCES The BTC Library hosts a substantial collection of textbooks and references on the subject of Instrumentation as well as links in its online catalog to free Instrumentation e book resources available on the Internet BTCInstrumentation channel on YouTube http www youtube com BTCInstrumentation hosts a variety of short video tutorials and demonstrations on instrumentation ISA Student Section at BTC meets regularly to set up industry tours raise funds for scholarships and serve as a general resource for Instrumentation students Membership in the ISA is 10 per year payable to the national ISA organization Membership includes a complementary subscription to InTech magazine ISA website http www isa org provides all of its standards in electronic format many of which are freely available to ISA members Normal Accidents by Charles Perrow ISBN 10 0691004129 ISBN 13 978 0691004129 Instrument Engineer s Handbook Volume 2 Process Control and Optimization edited by B la Liptak published by CRC Press 4th edition ISBN 10 0849310814 ISBN 13 978 0849310812 Purdy s Instrument Hand
54. e to intelligently choose what parameters to adjust and what closed loop behaviors to look for 87 Lab questions e Instrument connections e Determine correct wire connections between instruments to create a working 4 20 mA loop circuit based on diagrams of instruments with terminals labeled Correctly determine all electrical sources and loads as well as all voltage polarities and current directions in a 4 20 mA loop circuit based on diagrams of instruments with terminals labeled e Commissioning and Documentation e Identify and explain the distinction between direct and reverse control modes in the loop controller e Identify some of the main loads in your process and explain how they may be varied while the process is running Describe how to connect a loop calibrator to measure current output by a loop powered 2 wire transmitter e Describe how to connect a loop calibrator to measure current output by a controller e Describe how to connect a loop calibrator to simulate current coming from a loop powered 2 wire transmitter Describe how to connect a loop calibrator to simulate current coming from a self powered 4 wire transmitter Describe how to connect a loop calibrator to stroke a control valve e Mental math no calculator allowed e Convert a proportional band value into a gain value or vice versa Convert a repeats minute or second integral value into a minutes or seconds repeat integral value or vice versa Calcu
55. eam environment and with full access to references notes and instructor assistance perform the following tasks Demonstrate proper use of safety equipment and application of safe procedures while using power tools and working on live systems Communicate effectively with teammates to plan work arrange for absences and share responsibilities in completing all labwork Construct and commission an automatically controlled process using a PID controller Generate an accurate loop diagram compliant with ISA standards documenting your team s control system Commission and decommission a WirelessHART instrument Configure a digital indicator to poll instrument data via the Modbus protocol e Independently perform the following tasks with 100 accuracy mastery Multiple re tries are allowed with different specifications conditions each time Connect an electromechanical interposing relay to energize a 120 VAC load using a DC control circuit given components and criteria randomly selected by the instructor Build a circuit and configure a HART compatible DP transmitter to measure an applied pressure or vacuum according to criteria randomly selected by the instructor Diagnose a random fault placed in another team s control system by the instructor within a limited time using no test equipment except a multimeter logically justifying your steps in the instructor s direct presence COURSE OUTLINE A course calendar in el
56. ectronic format Excel spreadsheet resides on the Y network drive and also in printed paper format in classroom DMC130 for convenient student access This calendar is updated to reflect schedule changes resulting from employer recruiting visits interviews and other impromptu events Course worksheets provide comprehensive lists of all course assignments and activities with the first page outlining the schedule and sequencing of topics and assignment due dates These worksheets are available in PDF format at http www ibiblio org kuphaldt socratic sinst e INST262 Section 1 Feedback control systems 4 days theory and labwork e INST262 Section 2 DDC and DCS platforms 4 days theory and labwork 1 day for mastery proportional Exams e INST262 Section 3 FOUNDATION Fieldbus 4 days theory and labwork 6 INST262 Section 4 Wireless instrumentation 4 days theory and labwork 1 day for mastery proportional Exams METHODS OF INSTRUCTION Course structure and methods are intentionally designed to develop critical thinking and life long learning abilities continually placing the student in an active rather than a passive role Independent study daily worksheet questions specify reading assignments problems to solve and experiments to perform in preparation before classroom theory sessions Open note quizzes and work inspections ensure accountability for this essential preparatory work The purpose of this is to convey information and
57. ed by each student individually A listing of potential lab questions are shown at the end of this worksheet question The lab questions are intended to guide your labwork as much as they are intended to measure your comprehension and as such the instructor may ask these questions of your team day by day rather than all at once on a single day It is essential that your team plans ahead what to accomplish each day A short 10 minute team meeting at the beginning of each lab session is a good way to do this reviewing what s already been done what s left to do and what assessments you should be ready for There is a lot of work involved with building documenting and troubleshooting these working instrument systems As you and your team work on this system you will invariably encounter problems You should always attempt to solve these problems as a team before requesting instructor assistance If you still require instructor assistance write your team s color on the lab whiteboard with a brief description of what you need help on The instructor will meet with each team in order they appear on the whiteboard to address these problems Cut out tag s with scissors then affix to instrument s using transparent tape to show calibration CALIBRATED CALIBRATED CALIBRATED CALIBRATED Date Date Date Date SS By By By By Range Range Range Range 75 Lab Exercise
58. element that influences the process variable e g a control valve motor drive or some other final control device and finally the process itself which reacts to the final control device s actions Decides Senses Influences You can check each element of your feedback control loop by comparing its input with its output to see if each element is doing what it should 1 Decision making Carefully examine the controller faceplate looking at the values of PV SP and Output Is the controller taking appropriate action to force PV equal to SP In other words is the Output signal at a value you would expect if the controller were functioning properly to regulate the process variable at setpoint If so then the controller s action and tuning are most likely not at fault If not then the problem definitely lies with the controller 2 Sensing Compare the controller s displayed value for PV with the actual process variable value as indicated by local gauges by feel or by any other means of detection If there is good correspondence between the controller s PV display and the real process variable then there probably isn t anything wrong with the measurement portion of the control loop e g transmitter impulse lines PV signal wiring analog input of controller etc If the displayed PV disagrees with the actual process variable value then something is definitely wrong here 3 Influencing Compare the controller s displayed
59. er for practice Day 3 Theory session topic Loop controller function block programming Questions 41 through 60 answer questions 41 45 in preparation for discussion remainder for practice Day 4 Theory session topic DCS configuration Questions 61 through 80 answer questions 61 68 in preparation for discussion remainder for practice Feedback questions 81 through 90 are optional and may be submitted for review at the end of the day How To Access the worksheets and textbook go to the Socratic Instrumentation website located at http www ibiblio org kuphaldt socratic sinst to find worksheets for every 2nd year course section organized by quarter as well as both the latest stable and development versions of the Lessons In Industrial Instrumentation textbook Download and save these documents to your computer Maximize your learning come to school prepared each and every day this means completing all your homework before class starts Use every minute of class and lab time productively Follow all the tips outlined in Question 0 in every course worksheet as well as your instructor s advice Don t ask anyone to help you solve a problem until you have made every reasonable effort to solve it on your own Identify upcoming assignments and deadlines read the first page of each course worksheet Relate course days to calendar dates reference the calendar spreadsheet file calendar x1sx
60. er output decreases 101 Answer 15 One possible fault has to do with the control valve perhaps something has happened to make it fail closed loss of air supply signal etc Other possible problems include the following e Pump not running no source of fluid power to motivate flow e Very poor controller tuning e Wrong controller action e Valve failed closed loss of air supply signal etc e Transmitter failed showing no flow when in fact there is A good first test for troubleshooting the loop is to check the controller output is it trying to open up the valve Answer 16 Answer 17 Answer 18 Answer 19 Answer 20 Answer 21 Answer 22 Answer 23 Answer 24 Answer 25 Answer 26 Answer 27 Answer 28 The automatic mode is proper and the low output signal value tells us the controller is doing all it can to bring the temperature down The problem therefore is not in the controller s automatic response 102 Answer 29 Example 1 increasing temperature operator should close the valve more Example 2 increasing level operator should open the valve more Example 3 increasing flow operator should close the valve more Example 4 increasing temperature operator should open the valve more The goal with these questions is to think like an operator in order to have a clear understanding of the process s needs Only when one recognizes the
61. evel Density of dry air at 20 C and 760 torr 1 204 mg cm 1 204 kg m 0 075 lb ft 0 00235 slugs ft Absolute viscosity of dry air at 20 C and 760 torr 0 018 centipoise cp 1 8 x 1075 Pascal seconds Pa s file conversion_constants 18 Question 0 How to get the most out of academic reading Articulate your thoughts as you read i e have a conversation with the author This will develop metacognition active supervision of your own thoughts Write your thoughts as you read noting points of agreement disagreement confusion epiphanies and connections between different concepts or applications These notes should also document important math formulae explaining in your own words what each formula means and the proper units of measurement used Outline don t highlight Writing your own summary or outline is a far more effective way to comprehend a text than simply underlining and highlighting key words A suggested ratio is one sentence of your own thoughts per paragraph of text read Note points of disagreement or confusion to explore later Work through all mathematical exercises shown within the text to ensure you understand all the steps Imagine explaining concepts you ve just learned to someone else Teaching forces you to distill concepts to their essence thereby clarifying those concepts revealing assumptions and exposing misconceptions Your goal is to create the simplest explana
62. f Fall Winter and Spring quarters Prerequisite for all INST24x INST25x and INST26x courses gt Prerequisite for INST206 Offered 1 week of Fall Winter and Spring quarters 10 The particular sequence of courses you take during the second year depends on when you complete all first year courses and enter the second year Since students enter the second year of Instrumentation at four different times beginnings of Summer Fall Winter and Spring quarters the particular course sequence for any student will likely be different from the course sequence of classmates Some second year courses are only offered in particular quarters with those quarters not having to be in sequence while others are offered three out of the four quarters and must be taken in sequence The following layout shows four typical course sequences for second year Instrumentation students depending on when they first enter the second year of the program Possible course schedules depending on date of entry into 2nd year Beginning in Summer Beginning in Fall Beginning in Winter Beginning in Spring Jan Winter quarter INST 200 1 wk Intro to Instrumentation INST 250 5 cr Final Control Elements INST 251 5 cr PID Control INST 252 4 cr Loop Tuning CHEM amp 161 5 cr Chemistry Jan Winter quarter INST 205 1 cr Job Prep INST 250 5 cr Final Control Elements Mar
63. g 4 to 20 milliamps The installation is brand new and you have not yet received the custom scale for the analog indicator showing 40 to 240 PSI Instead the indicator s face simply reads 4 to 20 milliamps For the time being the operators need a way to translate the milliamp number value read on the indicator into a PSI number value they can relate to the process Write simple instructions for calculating PSI from any milliamp value they happen to read off this pressure indicator s face file 102452 68 Question 85 Use Kirchhoff s Current Law to calculate the magnitudes and directions of currents through all resistors in this circuit Note all current arrows point in the direction of conventional flow file 101162 69 Question 86 Suppose a voltmeter connected between test points D and F registers 5 V in this circuit Current mirror 18 volts 0 5 amps current limited eee 1kQ Q regulates current at 5 mA Identify the likelihood of each specified fault for this circuit Consider each fault one at a time i e no coincidental faults determining whether or not each fault could independently account for all measurements and symptoms in this circuit Fault Possible Impossible Ry failed open R failed open R failed open Q failed open R failed shorted R failed shorted Rs failed shorted Q failed shorted Voltage source dead
64. g the proper size and type of screwdriver never using any tool that mars the fastener such as pliers or vise grips unless absolutely necessary Pliers e Needle nose pliers e Tongue and groove pliers sometimes called Channel lock pliers e Diagonal wire cutters sometimes called dikes Screwdrivers e Slotted 1 8 and 1 4 shaft e Phillips 1 and 2 e Jeweler s screwdriver set e Optional Magnetic multi bit screwdriver e g Klein Tools model 70035 Electrical e Multimeter Fluke model 87 IV or better e Alligator clip jumper wires e Soldering iron 10 to 40 watt and rosin core solder e Resistor potentiometer diode assortments from first year lab kits e Package of insulated compression style fork terminals 14 to 18 AWG wire size 10 stud size e Wire strippers terminal crimpers for 10 AWG to 18 AWG wire and insulated terminals e Optional ratcheting terminal crimp tool e g Paladin 1305 Ferrules Direct FDT10011 or equivalent Safety e Safety glasses or goggles available at BTC bookstore e Earplugs available at BTC bookstore Miscellaneous e Simple scientific calculator non programmable non graphing no conversions TI 30Xa or TI 30XIIS recommended Required for some exams Masking tape for making temporary labels Permanent marker pen Teflon pipe tape Utility knife Tape measure 12 feet minimum Flashlight An inexpensive source of tools is your local pawn shop Look for tools with unlimited
65. g those conductors to short together what will happen in this system Where would you expect to measure voltage in the loop circuit and where would you expect to measure no voltage in the loop circuit Where would you expect to measure current in the loop circuit and where would you expect to measure no current in the loop circuit e Calculate the loop current value when the pH measures 6 8 inside the neutralization tank Suggestions for Socratic discussion e For those who have studied pH measurement explain why pH neutralization is an important control process in industry e How can we tell from this diagram whether the 4 20 mA output of transmitter AIT 41 is active or passive i e sourcing or sinking file 100239 55 Question 45 A DDC Direct Digital Control system used for building automation sends a 4 20 mA control signal to a steam valve with an electronic positioner This particular loop has a problem for the valve remains in the full closed 0 position regardless of what the DDC tries to tell it to do A technician begins diagnosing the problem by taking a DC voltage measurement at terminal block TB 11 in this loop circuit Sa A Ser We cable 41 S Fa lt o 2 Cy 000v ay cable 30 lt le ic TB 11 DDC system a cable aas n cable 16 Analo lt d E To other field devices cable 19 re Processor on input cable 24 di Andog input The technicia
66. hese process control loops and how the results of that thought experiment are helpful to answering the question e Explain how to reliably identify the process variable PV in any controlled process presented to you e Explain how to reliably identify the manipulated variable MV in any controlled process presented to you Identify and explain the deleterious effect s caused by a process controller configured with the wrong action Identify an instrument mis calibration or mis configuration that could cause the process variable to settle at a greater value than it should be assuming all other components in the system are functioning properly Once you have identified the proper controller action for any given process example identify something that could be altered about the process to require the other control action file 100788 28 Question 6 In this process hot steam is used to strip volatile sulfur compounds from process water inside a vessel called a stripping tower A flow control system loop 28 regulates the amount of stripping steam admitted to the tower v0 P 201 Paor P 102 102 c7 E2 SOUR WATER TANK SOUR WATER TANK EJECTOR COOLING WATER PUMP SOUR WATER PUMP STRIPPED WATER PUMP SOUR WATER STRIPPER SOUR WATER HEATER 8 0 Dia 12 0 Sidewal 85 ACFM 1 H20 20GPM 80 F 5GPM 80 F BGPM 150 F 12 xar SS R 100 METUHR DP Atmosphere Rated head 80 PSI Rated head 75 PSI Rated head 60 PSI DP 55 PSIG TOPSI 360F
67. hich are connected identically to the standard Factory Configured Option 101 program then identify those function blocks which are different Explain why anyone would wish to have a loop controller equipped with a PWM output instead of a 4 20 mA analog output Explain how this analog circuit functions to produce a PWM output signal from a sawtooth waveform and a DC reference signal and how this functionality is mimicked by the function block program of the Siemens 353 controller V V AA THL Sawtooth wave NG Pa PWM output Comparator DC reference signal in Suggestions for Socratic discussion e Describe the steps necessary to edit the FCO 101 program so that it resembles this program using the faceplate pushbutton controls and displays e Which way would you have to move the wiper on the potentiometer in the analog circuit in order to increase the duty cycle of the PWM output What would be the effect of the V power source connection to the potentiometer failing open What would be the effect of the ground connection to the potentiometer failing open What would be the effect of the sawtooth wave generator connection failing with a 0 volt output What would be the effect of the V power source connection to the comparator failing open Sketch the diagram of an interposing circuit that can take the opamp s output signal and amplify it to drive PWM power to a large electric heating element e g rated at a m
68. iagram off of a team mate s diagram rather than closely inspecting the system for yourself Not placing loop sheet instruments in the correct orientation field instruments on the left control room instruments on the right Creating and inspecting accurate loop diagrams should take no more than one full lab session 3 hours if the team is working efficiently Creating and inspecting accurate P amp IDs will take more time but not an entire lab session 3 hours 83 Lab Exercise operating the system All networked loop controllers in the lab DCS DDC PLC single loop networked provide graphing functionality so that you may plot your process variable PV and output values over time This graphical data is essential for tuning PID controlled loops If you happen to be using a controller that does not provide graphing capability your team must attach a trend recorder and or a data acquisition unit plus a personal computer to the necessary signal cables so that these values are recorded over time PID tuning is a subject worthy of its own course and so you will not be expected to achieve perfect control on your process You will find however that one of the best ways to learn PID tuning is by playing with your process as it responds to different tuning parameters entered into the loop controller The expectation for good control behavior in the context of this lab exercise is for the loop to exhibit response that is no less
69. ignments for this course are thoroughly documented in the following course worksheets located at http www ibiblio org kuphaldt socratic sinst index html INST262_sec1 pdf INST262_sec2 pdf INST262_sec3 pdf INST262_sec4 pdf EVALUATION AND GRADING STANDARDS out of 100 for the course grade e Completion of all mastery objectives 50 Mastery exam scores first attempt 10 2 exams at 5 each Proportional exam scores 30 2 exams at 15 each Lab questions 10 2 question sets at 5 each Quiz penalty 1 per failed quiz Tardiness penalty 1 per incident 1 free tardy per course Attendance penalty 1 per hour 12 hours sick time per quarter Extra credit 5 per project assigned by instructor based on individual learning needs All grades are criterion referenced i e no grading on a curve 100 gt A gt 95 95 gt A gt 90 90 gt B gt 86 86 gt B gt 83 83 gt B gt 80 80 gt C gt 76 76 gt C gt 73 73 gt C gt 70 minimum passing course grade 70 gt D gt 66 66 gt D gt 63 63 gt D gt 60 60 gt F A graded preparatory quiz at the start of each classroom session gauges your independent learning prior to the session A graded summary quiz at the conclusion of each classroom session gauges your comprehension of important concepts covered during that session If absent during part or all of a classroom session you may receive credit
70. imal temperatures for anaerobic bacteria to digest the manure and produce biogas approximately 105 F Coolant pump Pintan Exhaust BDS ia ae a a i SoS See See eee Ss Hot coolant Sulfide scrubber R 103 Compressor Effluent P 2 Suppose digester R 102 is found to be at only 97 F as indicated by a thermometer placed inside R 102 by an operator even though temperature indicating controller TIC 48 shows the temperature at the outlet of the heat exchanger to be right at setpoint 105 F An instrument technician checks the calibration of TT 48 and finds it to be within 1 of range 50 to 150 F Identify a probable cause for low temperature in R 102 and also how you would proceed to diagnose the process problem Suggestions for Socratic discussion e Is there enough information provided in this P amp ID to determine the proper direction of action for temperature controller TIC 48 Why or why not e Is there enough information provided in this P amp ID to determine the proper direction of action for temperature controller TIC 43 Why or why not 31 e Suppose an engineer suggested the reactor vessels be heated by electric heating elements powered by an electric generator turned by the engine Do you think this is a better or worse idea than using heat from the engine s coolant loop Explain why or why not e For those who have studied control valve sequencing identify the proper form of split rang
71. ing for control valves LV 55a and LV 55b file 101432 Question 9 Suppose an electric oven is equipped with a temperature sensitive control switch which is wired to a control relay to send electric power to its heating element Oven Control circuit diagram Element So e EE Electric heating element terminals How would this simple on off control system respond to changes in oven temperature in its effort to maintain temperature at the setpoint Be detailed in your explanation of the temperature switch and relay circuit s behavior Also sketch a graph of the oven temperature over time Setpoint 245 Fa Temperature Time gt file 101449 32 Question 10 One of the problems with simple on off control is that the final control element cycles frequently In real life this may be a problem because frequent cycling means more wear and a shortened lifespan for the component An answer to this problem of frequent cycling is to design the system to have a gap or a band of control rather than a single setpoint In effect there are two setpoints an upper and a lower setpoint This is commonly referred to as differential gap control or alternatively as on off control with deadband Shown here is a simple switch and relay circuit for a differential gap oven temperature control Oven Control circuit diagram L 340 F 350 F TSL TSH Element See eee es a Electric heating element te
72. it measured e What is the final control element and how does it exert control over the process variable e What safety hazards exist in this process related to control e g danger of explosion solidification production of dangerous byproducts etc e How far am I allowed to bump the process while I tune the controller and monitor the response e How is the controller mode switched to manual just in case I need to take over control e In the event of a dangerous condition caused by the controller how do you shut the process down Step 2 Understand what the settings on the controller do Is your controller configured for gain or proportional band Minutes per repeat or repeats per minute Does it use reset windup limits Does rate respond to error or PV alone You had better understand what the PID values do to the controller s action if you are going to decide which way and how much to adjust them Back in the days of analog electronic and pneumatic controllers I would recommend to technicians that they draw little arrow symbols next to each adjustment knob showing which way to turn for more aggressive action this way they wouldn t get mixed up figuring out gain vs PB rep min vs min rep etc all they had to think of is more or less of each action Step 3 Manually bump the manipulated variable final control element to learn how the process responds In manual mode you are the controller Wha
73. itical thinking and problem solving where the instructor s attention is best applied Classroom theory sessions usually begin with either a brief Q amp A discussion or with a Virtual Troubleshooting session where the instructor shows one of the day s diagnostic question diagrams while students propose diagnostic tests and the instructor tells those students what the test results would be given some imagined virtual fault scenario writing the test results on the board where all can see The students then attempt to identify the nature and location of the fault based on the test results Each student is free to leave the classroom when they have completely worked through all problems and have answered a summary quiz designed to gauge their learning during the theory session If a student finishes ahead of time they are free to leave or may help tutor classmates who need extra help The express goal of this inverted classroom teaching methodology is to help each student cultivate critical thinking and problem solving skills and to sharpen their abilities as independent learners While this approach may be very new to you it is more realistic and beneficial to the type of work done in instrumentation where critical thinking problem solving and independent learning are must have skills 13 Lab In the lab portion of each course students work in teams to install configure document calibrate and troubleshoot w
74. laining how an SFC could be used to help automate some real life process file 100815 Question 70 Question 71 Question 72 Question 73 Question 74 Question 75 Question 76 Question 77 Question 78 Question 79 63 Question 80 64 Question 81 Examine this loop diagram for a chemical reactor heating control system then determine how the system will respond to any one of the scenarios listed below you choose Your answer should describe four parameters of the control system over time 1 What happens to the process temperature 2 What the operator s indication does 3 Which direction the controller s output changes and 4 What happens to steam flow through the control valve Loop Diagram Reactor 15 A temperature control Revised by M Hott Date Feb 30 1999 i Field Field i Field process area panel P5 panel P30 DCS cabinet Steam Feed in Reactor 15 A TV 37 Cbi TV37 TB12 Chil OE FTA AO Node 9 Module 31 9 y rA cbiTTy37 Coils a 2 ii RAB tr h kedhot 2 iI Red riper wt vt D 2 Wwa LE K37 J aval aa 11 yew 726 to z at D 4G La 427 Tag number Description Manufacturer Model Calibration Notes TE 37 4 wire platinum RTD Chromalox 100 Q
75. late the pneumatic pressure in a 3 15 PSI range corresponding to x percent Calculate the electrical current in a 4 20 mA range corresponding to x percent Calculate the electrical voltage in a 1 5 volt range corresponding to x percent Calculate the percentage value of a pneumatic pressure signal x PSI in a 3 15 PSI range Calculate the percentage value of an electrical current signal x mA in a 4 20 mA range Calculate the percentage value of an electrical voltage signal x volts in a 1 5 volt range Diagnostics e Explain how to distinguish an open cable fault from a shorted cable fault using only a voltmeter no current or resistance measurement but assuming you are able to break the circuit to perform the test Explain how to use the manual mode of a process controller as a diagnostic test to check for problems in a control system Determine whether or not a given diagnostic test will provide useful information given a set of symptoms exhibited by a failed system Identify at least two plausible faults given the results of a diagnostic test and a set of symptoms exhibited by a failed system Propose a diagnostic test for troubleshooting a failed system and then explain the meanings of two different test results file 101558 88 Question 92 The Rules of Fault Club 1 Don t try to find the fault by looking for it perform diagnostic tests instead 2 Don t try to find the fault by looking for it perf
76. n decrease setpoint Left Button decrease output Right Button increase output An operator might wish to manually control a process in the event that the transmitter providing the process variable PV signal fails Answer 32 One of the better simulations I ve found is from Dex Automation You can run the free Java application streaming on the website or you can pay a small fee for a stand alone executable to run offline 103 Answer 33 When a controller is in the automatic mode output tracking means the manual output value follows along tracks the automatic output value so that when the controller is switched to manual mode the transition will be bumpless When a controller is in the manual mode setpoint tracking means the setpoint value follows along tracks the process variable value so that when the controller is switched to automatic mode the setpoint will begin at the same value as the process variable and control starts with no error In other words setpoint tracking means the controller assumes the process is where you want it to be at the moment you switch to automatic mode Answer 34 Answer 35 Answer 36 Answer 37 Answer 38 Answer 39 Answer 40 Answer 41 Answer 42 Answer 43 Answer 44 Partial answer e If a wire breaks loose at TB56 4 creating an open fault in the loop circuit determine what will happen
77. n knows a reading of 0 volts could indicate either an open fault or a shorted fault in the wiring Based on the location of the measured voltage 0 00 VDC determine where in the wiring a single open fault would be located if that is the culprit and also where in the wiring a short fault would be located if that is the culprit For the next diagnostic test the technician disconnects the red wire of cable 30 where it attaches to the screw terminal on TB 11 and re measures voltage at TB 11 After disconnecting the wire the new voltage measurement at TB 11 still reads 0 00 volts Determine what this result tells us about the nature and location of the fault Suggestions for Socratic discussion e Explain why it is critically important to determine the identities of the valve and DDC card as being either electrical sources or electrical loads when interpreting the diagnostic voltage measurements e Identify some of the pros and cons of this style of testing measuring voltage at a set of points before and after a purposeful wiring break compared to other forms of multimeter testing when looking for either an open or a shorted wiring fault e Identify a fault other than open or shorted cables which could account for all the symptoms and measurements we see in this troubleshooting scenario file i00792 56 Question 46 Question 47 Question 48 Question 49 Question 50
78. nal and counter productive Question 0 of every worksheet lists practical study tips Independent Problem Solving The best instrument technicians are versatile problem solvers General problem solving is arguably the most valuable skill you can possess for this career and it can only be built through persistent effort This is why you must take every reasonable measure to solve problems on your own before seeking help It is okay to be perplexed by an assignment but you are expected to apply problem solving strategies given to you see Question 0 and to precisely identify where you are confused so your instructor will be able to offer targeted help Asking classmates to solve problems for you is folly this includes having others break the problem down into simple steps The point is to learn how to think on your own When troubleshooting systems in lab you are expected to run diagnostic tests e g using a multimeter instead of visually seeking circuit faults as well as consult the equipment manual s before seeking help Initiative No single habit predicts your success or failure in this career better than personal initiative which is why your instructor will demand you do for yourself rather than rely on others to do for you Examples include setting up and using your BTC email account to communicate with your instructor s consulting manuals for technical information before asking for help regularly checking the course calendar and a
79. nnect and use DAQ hardware and software to monitor electrical parameters in a system is a valuable diagnostic skill in this career You will find your teammates who have already taken the Measurement course series INST24X will be very helpful in showing you how to check configure calibrate and install the measuring instrument s you will need for your process Planning a functioning system should take no more than an hour if the team is working efficiently and will save you hours of frustration and possible component destruction 79 Lab Exercise circuit design challenge Your instructor will choose one 4 20 mA field instrument and one control system from the lists shown below for which you must sketch an accurate circuit diagram showing how the two instruments would connect to each other If this interconnection between controller and field instrument requires additional electrical components to function e g DC or AC power source precision 250 Q resistor diode relay etc those must be incorporated into your diagram as well Instruction manuals for all instrument listed are available on the electronic Instrumentation Reference for your convenience When your sketch is complete you must show the relevant manual pages to your instructor for verification of correct connections This exercise tests your ability to locate appropriate information in technical manuals and design a correct 4 20 mA analog signal circuit for a given pair
80. nswers for all worksheet questions not just passing daily quizzes as is the standard for conventional students The instructor will discuss any incomplete and or incorrect worksheet answers with the student and ask that those questions be re answered by the student to correct any misunderstandings before moving on Labwork is perhaps the most difficult portion of the curriculum for a distance student to complete since the equipment used in Instrumentation is typically too large and expensive to leave the school lab facility Distance students must find a way to complete the required lab activities either by arranging time in the school lab facility and or completing activities on equivalent equipment outside of school e g at their place of employment if applicable Labwork completed outside of school must be validated by a supervisor and or documented via photograph or videorecording Conventional students may opt to switch to distance mode at any time This has proven to be a benefit to students whose lives are disrupted by catastrophic events Likewise distance students may switch back to conventional mode if and when their schedules permit Although the existence of alternative modes of student participation is a great benefit for students with challenging schedules it requires a greater investment of time and a greater level of self discipline than the traditional mode where the student attends school for 6 hours every d
81. nuals in the Instrumentation Reference or online to identify the proper wire terminals to connect then sketch a simple loop diagram showing how the appropriate terminals on each device connect to terminals on the other devices to make a functional instrument loop You are free to choose which channel on the DeltaV I O cards to use for your loop Suggestions for Socratic discussion e A problem solving technique useful for making proper connections in pictorial circuit diagrams is to first identify the directions of all DC currents entering and exiting component terminals as well as the respective voltage polarity marks for those terminals based on your knowledge of each component acting either as an electrical source or an electrical load Discuss and compare how these arrows and polarity marks simplify the task of properly connecting wires between components e Locate a wiring diagram for one of the redundant I O card options available for the DeltaV system either M series or S series and reference that diagram to explain how redundant I O cards connect to the same field instrument file 100818 Question 69 Read Exercise 8 Creating a Sequential Function Chart in Chapter 4 Creating and Downloading the Control Strategy of the Getting Started with your DeltaV Digital Automation System manual document D800002X122 March 2006 and answer the following questions Describe what a SFC program does exp
82. o software to examine this loop s function block program module in online mode this is what you see 00 BKCAL_IN BKCAL_OUT CAS_IN OUT_D FF_VAL OUT oy CAS_IN BKCAL_OUT Al GUT pa inf PID 75 AO jour TRK_IN_D TO_IN CTRL 01 101 C04 CHO5 FIELD_VAL_PCT TRK_VAL Romar Identify the likelihood of each specified fault in this process based on what you see in the online Control Studio view Consider each fault one at a time i e no coincidental faults determining whether or not each fault could independently account for all measurements and symptoms in this process Fault Possible Impossible Poor tuning in the PID function block LT 35 miscalibrated reading too low LT 35 miscalibrated reading too high Make up water source shut off Pump P 103 failed not pumping LG 31 sightglass block valve plugged Pump P 105 failed not pumping Human operator error file 100961 62 Question 68 Sketch a diagram showing all wire connections between any model of Rosemount differential pressure transmitter an Emerson DeltaV DCS controller and a Fisher DVC6020 valve positioner to form a simple PID control system You may arbitrarily choose to use either M series or S series DeltaV I O cards Your task is to locate the appropriate datasheets or ma
83. of instruments The electronic Instrumentation Reference will be available to you in order to answer this question Since all 4 20 mA loops are basically series DC circuits it is highly recommended that you approach their design the same as for any other DC circuit carefully identify all sources and loads in the circuit trace directions of all currents and mark the polarities of all voltages Most of the mistakes made in this type of circuit design challenge may be remedied by careful consideration of these specific circuit analysis details 4 20 mA transmitter options e Pressure Rosemount 1151 Alphaline analog 1151 HART or 3051 HART Yokogawa DPharp EJX110A or EJX910 Honeywell ST3000 e Level Rosemount APEX non contact radar 3300 GWR or 5300 GWR e Temperature Rosemount 444 644 3044 or 3144 Foxboro RTT15 or RTT30 Moore Industries SPT with sourcing 4 wire 4 20 mA output Moore Industries SPT with sinking 2 wire 4 20 mA output Moore Industries TRX or TDY e Flow Foxboro CFT50 coriolis e Analytical Rosemount 5081 P pH Daniel 700 gas chromatograph 4 analog output channels Foxboro 876PH pH ORP ISE 80 Controller options e Monolithic Siemens 352P Siemens 353 Foxboro 716C Foxboro 718TC Foxboro 762CNA Moore Industries 535 Honeywell UDC2300 Honeywell UDC3500 e Modular you choose the appropriate I O module Siemens 353R Emerson ROC800 SCADA
84. offenses are grounds for immediate termination in this career and as such will not be tolerated here file expectations Course Syllabus INSTRUCTOR CONTACT INFORMATION Tony Kuphaldt 360 752 8477 office phone 360 752 7277 fax tony kuphaldt btc ctc edu DEPT COURSE INST 262 CREDITS 5 Lecture Hours 22 Lab Hours 70 Work based Hours 0 COURSE TITLE Digital Control Systems COURSE DESCRIPTION This course teaches the basic principles of distributed instrumentation including distributed control systems DCS FOUNDATION Fieldbus instruments and wireless field instruments Pre Corequisite course INST 260 Data Acquisition Systems Prerequisite course MATH amp 141 Precalculus 1 with a minimum grade of C COURSE OUTCOMES Commission analyze and efficiently diagnose instrumented systems incorporating networked control platforms DCS Fieldbus wireless COURSE OUTCOME ASSESSMENT DCS and Fieldbus system commissioning analysis and diagnosis outcomes are ensured by measuring student performance against mastery standards as documented in the Student Performance Objectives Failure to meet all mastery standards by the next scheduled exam day will result in a failing grade for the course STUDENT PERFORMANCE OBJECTIVES e Without references or notes within a limited time 3 hours total for each exam session independently perform the following tasks Multiple re tries are allowed on mastery 100 accuracy objec
85. ol that eliminates offset quickly while minimizing overshoot and oscillation of the process variable Suggestions for Socratic discussion e Explain in your own words why more repeats per minute yields a more aggressive integral response and why more minutes per repeat yields a tamer integral response file 104290 Question 26 Desktop Process exercise Tune the controller in your Desktop Process first using proportional action only reset and rate settings at minimum effect testing the control quality by observing the graph produced by the data acquisition software Your goal is quick response to setpoint changes with minimal oscillation of the PV After determining a reasonable value for the controller s gain setting incorporate some reset integral action in order to eliminate offset following a setpoint or load change Once again your goal is quick response with minimal oscillation and overshoot of the PV Record these gain and reset settings for future use file 104292 42 Question 27 Desktop Process exercise Configure your Desktop Process for full proportional plus integral plus derivative PID control Experiment with different gain reset and rate tuning parameter values until reasonably good control is obtained from the process i e fast response to setpoint changes with minimal overshoot good recovery from load changes Record the
86. op diagrams are shown in the next question in this worksheet These loop diagrams must be comprehensive and detailed showing every wire connection every cable every terminal block range points etc The principle to keep in mind here is to make the loop diagram so complete and unambiguous that anyone can follow it to see what connects to what even someone unfamiliar with industrial instrumentation In industry loops are often constructed by contract personnel with limited understanding of how the system is supposed to function The loop diagrams they follow must be so complete that they will be able to connect everything properly without necessarily understanding how it is supposed to work Every instrument and every signal cable in your loop needs to be properly labeled with an ISA standard tag number An easy way to do this is to wrap a short piece of masking tape around each cable and placed on each instrument then writing on that masking tape with a permanent marker Although no industry standard exists for labeling signal cables a good recommendation is to label each two wire cable with the tag number of the field instrument it goes to Thus every length of two wire cable in a pressure transmitter circuit should be labeled PT a where x is the loop number every flow control valve should be labeled FV x etc Remember that the entire loop is defined by the process variable it measures if the PV is temperature then the transmit
87. orking instrument loop systems Each lab exercise focuses on a different type of instrument with a eight day period typically allotted for completion An ordinary lab session might look like this 1 Start of practical lab session announcements and planning a The instructor makes general announcements to all students b The instructor works with team to plan that day s goals making sure each team member has a clear idea of what they should accomplish 2 Teams work on lab unit completion according to recommended schedule First day Select and bench test instrument s One day Connect instrument s into a complete loop One day Each team member drafts their own loop documentation inspection done as a team with instructor One or two days Each team member calibrates configures the instrument s Remaining days up to last Each team member troubleshoots the instrument loop 3 End of practical lab session debriefing where each team reports on their work to the whole class Troubleshooting assessments must meet the following guidelines e Troubleshooting must be performed on a system the student did not build themselves This forces students to rely on another team s documentation rather than their own memory of how the system was built e Each student must individually demonstrate proper troubleshooting technique e Simply finding the fault is not good enough Each student must consistently demonstrate sound reasoning while tro
88. orm diagnostic tests instead 3 The troubleshooting is over when you have correctly identified the nature and location of the fault 4 It s just you and the fault don t ask for help until you have exhausted your resources 5 Assume one fault at a time unless the data proves otherwise 6 No new components allowed replacing suspected bad components with new is a waste of time and money 7 We will practice as many times as we have to until you master this 8 Troubleshooting is not a spectator sport you have to troubleshoot These rules are guaranteed to help you become a better troubleshooter and will be consistently emphasized by your instructor 89 06 Loop Diagram Revised by Date si Tea _Peseripven_ Menuracturer _Medel Input range Input range _ Output range ouputrenae Mets eye duie wmeaIsSerp doo Loop diagram requirements Perhaps the most important rule to follow when drafting a loop diagram is your diagram should be complete and detailed enough that even someone who is not an instrument technician could understand where every wire and tube should connect in the system Instrument bubbles Proper symbols and designations used for all instruments All instrument bubbles properly labeled letter codes and loop numbers All instrument bubbles marked with the proper lines solid line dashed line single line double lines no lines Optional Calibration ranges and ac
89. other form of link supported by DeltaV_Run In this discussion the tutorial mentions that trend links are able to display any floating point data i e any parameter reference ending in F_ Explain what floating point data is and how it differs from integer or boolean data Suggestions for Socratic discussion e Access a DeltaV workstation PC and try opening an operator picture using DeltaV Operate Configure Explore the parameters associated with the datalinks and dynamos in this picture Do not download or save anything which will alter the configuration of the DCS just explore and observe e For those students who have studied HMI programming in their PLC coursework identify aspects of DeltaV Operate that are similar to other HMIs you have worked with e Identify practical applications where you might wish to show integer data on an operator display e Identify practical applications where you might wish to show boolean data on an operator display file 100817 60 Question 67 The scrubber vessel V 5 liquid level is being controlled by an Emerson DeltaV DCS but something is wrong The operator reports seeing a liquid level of 90 in the LG 31 sightglass while claiming the setpoint entered into the DeltaV Operate controller faceplate is 75
90. ould begin troubleshooting this system and what possible faults could account for the controller not being able to maintain liquid flow at setpoint Suggestions for Socratic discussion e Explain how you could divide this control system into distinct areas or zones which you may then begin to refer to when dividing and conquering the problem file 102518 Question 16 Question 17 Question 18 Question 19 Question 20 Question 21 Read and outline the Integral Reset Control section of the Closed Loop Control chapter in your Lessons In Industrial Instrumentation textbook Note the page numbers where important illustrations photographs equations tables and other relevant details are found Prepare to thoughtfully discuss with your instructor and classmates the concepts and examples explored in this reading file 104284 38 Question 22 Read and outline the Derivative Rate Control section of the Closed Loop Control chapter in your Lessons In Industrial Instrumentation textbook Note the page numbers where important illustrations photographs equations tables and other relevant details are found Prepare to thoughtfully discuss with your instructor and classmates the concepts and examples explored in this reading file 104301 39 Question 23 Desktop Process exercise PID Proportional Integral Derivative closed loop control is a perplexing
91. r 75 Answer 76 Answer 77 Answer 78 Answer 79 Answer 80 Answer 81 This is a graded question no answers or hints given Answer 82 This is a graded question no answers or hints given Answer 83 This is a graded question no answers or hints given Answer 84 This is a graded question no answers or hints given Answer 85 This is a graded question no answers or hints given Answer 86 This is a graded question no answers or hints given Answer 87 This is a graded question no answers or hints given Answer 88 This is a graded question no answers or hints given Answer 89 This is a graded question no answers or hints given Answer 90 This is a graded question no answers or hints given Answer 91 Answer 92 Your loop diagram will be validated when the instructor inspects the loop with you and the rest of your team 106
92. rammable Logic Controller your prototype sketch must show how those devices will connect to typical input output terminals on the PLC where electrical power will be supplied etc Prototype sketches need not show all intermediary connections between components such as terminal blocks in junction boxes between the field device and the controller You should practice good problem solving techniques when creating your prototype sketch such as consulting equipment manuals for information on component functions and marking directions of electric current voltage polarities and identifying electrical sources loads Use this task as an opportunity to strengthen your analytical skills Remember that you will be challenged in this program to do all of this on your own during capstone assessments so do not make the mistake of relying on your teammates to figure this out for you instead treat this as a problem you must solve and compare your results with those of your teammates Your team s prototype sketch is so important that the instructor will demand you provide this plan before any construction on your team s working system begins Any team found constructing their system without a verified plan will be ordered to cease construction and not resume until a prototype plan has been drafted and approved Similarly you should not deviate from the prototype design without instructor approval to ensure nothing will be done to harm equipment by wa
93. rminals In the case of this electric oven differential gap control means the heating element will not turn on until the temperature falls below the lower setpoint and will not turn off until the temperature rises above the upper setpoint Upper setpoint 350 F Lower setpoint 340 F gt Temperature Tine Graph this oven s temperature over time as the control system operates and contrast its behavior against that of a single point on off control system file 101450 33 Question 11 Suppose a gas fired water heater is controlled manually with a human operator observing a temperature indicator on the hot water outlet pipe and actuating a fuel gas control valve Exhaust stack Water tubes Temperature indicator Control valve Does the operator play the part of a direct acting controller or a reverse acting controller in this process control scenario Also identify the process variable setpoint and manipulated variable in this manual control system file 101452 34 Question 12 In this process maple syrup is heated as it passes through a steam heat exchanger then enters an evaporator where the water boils off The purpose of this is to raise the sugar concentration of the syrup making it suitable for use as a food topping A level control system LT LIC and LV maintains constant syrup level inside the evaporator while an analytical control system AT AIR AC and AV
94. rolled and the flow controller modulate the bypass valve 77 Oven temperature control A cheap electric toaster oven or convection oven works well for this purpose The only hard to find part is the power controller JC which modulates AC power to the heating element in accordance with the temperature controller s 4 20 mA output signal Convection oven Solar air heater control For the purposes of this lab exercise the solar collector may be made out of cardboard with clear plastic food wrap as the cover material Paint the inside of the collector flat black for maximum heat absorption capability Use a variable frequency motor drive VFD if the fan is turned by an AC motor If using a DC fan e g computer cooling fan you may use a simpler PWM power controller Collector Air fan Other process ideas include Soldering iron temperature control blowing air over tip with variable speed fan Draft pressure control controlling very low air pressure inside of a box Pneumatic piston height control using lengths of PVC pipe to build a simple piston cylinder which may be used to lift small weights using modest air pressures A good way to control air pressure to the piston is to route the I P transducer s output to a volume booster relay and let the relay s output directly drive the piston Piston height may be sensed using a flexible water tube attached to the piston rod running to a stationary pressure
95. rry any motor current just enough current to energize the relay coil Motor Battery Relay plugged into socket file 103165 73 Question 90 Something is wrong with this building alarm system circuit The alarm siren refuses to energize even when all windows and doors are opened Vpp TP14 R Window switch closed when shut SW Window switch closed when shut SW TP5 TP9 Tpio Fuse L1 Door switch closed when shut SW TP3 TP11 120 VAC Door switch closed when shut N Solid state ay relay _ L2 TP12 Normal e TP13 Override TP15 Using your logic probe you measure a high signal at TP1 a high signal at TP15 and a low signal at TP8 with all windows and doors propped open and with the key switch in the normal position From this information identify two possible faults either one of which could account for the problem and all measured values in this circuit Then choose one of those possible faults and explain why you think it could be to blame The circuit elements you identify as possibly faulted can be wires traces and connections as well as components Be as specific as you can in your answers identifying both the circuit element and the type of fault e Circuit elements that are possibly faulted 1 2 e Explanation of why you think one of the above possibilities could be to blame
96. s and other relevant details are found Prepare to thoughtfully discuss with your instructor and classmates the concepts and examples explored in this reading file 104254 Question 2 Read and outline the On Off Control section of the Closed Loop Control chapter in your Lessons In Industrial Instrumentation textbook Note the page numbers where important illustrations photographs equations tables and other relevant details are found Prepare to thoughtfully discuss with your instructor and classmates the concepts and examples explored in this reading file 104255 Question 3 Read and outline the Proportional Only Control section of the Closed Loop Control chapter in your Lessons In Industrial Instrumentation textbook Note the page numbers where important illustrations photographs equations tables and other relevant details are found Prepare to thoughtfully discuss with your instructor and classmates the concepts and examples explored in this reading file 104256 Question 4 In any automated controlled system there is a process variable a setpoint and a manipulated variable There is also something called a load which influences how well the control system is able to maintain setpoint Provide a general description for a load and then identify the load s in each of the following manually controlled processes Example 1 Temperature control application Thermometer va To ga
97. s fuel supply 21 Example 2 Level control application Example 3 Flow control application 20 PSI air Orifice plate 22 Example 4 Temperature control application Steam out Steam in gt 10 50 mA Suggestions for Socratic discussion e Explain why ambient air temperature is considered a load to process example 4 but the insulation thickness on the heat exchanger is not file 101453 23 Question 5 In each of these process control examples the transmitter produces an increasing signal for an increase in process measurement level pressure temperature etc and the I P transducer produces an increasing air pressure signal out for an increasing current signal in Your task is to determine the proper action for the process controller either direct acting or reverse acting Remember a direct acting controller produces an increasing output signal with an increasing process variable input A reverse acting controller produces a decreasing output signal for an increasing process variable input It is essential for stability that the controller have the correct direction of action Example 1 Controller Air supply Transducer transmitter Air to close valve 24 Example 2 Controller Air supply Transducer transmitter Air to open valve Example 3 Cold fluid in Air to open valve Steam in Transducer Air supply Ppestqe W
98. s a result of this fault e Suppose this system were functioning perfectly well and then something pinched Cable 3 Pair 1 and caused it to fail shorted Explain what would happen as a result of this fault 44 file 101491 Question 29 Suppose you were giving instructions to a human operator regarding which way to move a hand operated control valve to maintain a process variable at setpoint In each of these examples determine which way the operator should move the valve to counteract an increase in the process variable resulting from some independent change in the process Example 1 Temperature control application Thermometer aw TI Temperature is too high Valve To gas fuel supply Should the operator move the valve further open or further closed 45 Example 2 Level control application Level is too high Should the operator move the valve further open or further closed Example 3 Flow control application FI Flow is too high 3 15 PSI 20 PSI air Should the operator move the valve Valve further open or further closed Orifice plate 46 Example 4 Temperature control application Steam out Steam in gt Note the oil and steam never contact each each other inside the exchanger steam flows inside a set of tubes while the oil flows outside those same tubes Heat transfers through the tube walls from the steam to the oil Should the operator move
99. ssignment deadlines avoiding procrastination fixing small problems before they become larger problems etc If you find your performance compromised by poor understanding of prior course subjects re read those textbook sections and use the practice materials made available to you on the Socratic Instrumentation website don t wait for anyone else to diagnose your need and offer help General Values and Expectations continued Safety You are expected to work safely in the lab just as you will be on the job This includes wearing proper attire safety glasses and closed toed shoes in the lab at all times implementing lock out tag out procedures when working on circuits with exposed conductors over 30 volts using ladders to access elevated locations and correctly using all tools If you need to use an unfamiliar tool see the instructor for directions Orderliness You are expected to keep your work area clean and orderly just as you will be on the job This includes discarding trash and returning tools at the end of every lab session and participating in all scheduled lab clean up sessions If you identify failed equipment in the lab label that equipment with a detailed description of its symptoms Teamwork You will work in instructor assigned teams to complete lab assignments just as you will work in teams to complete complex assignments on the job As part of a team you must keep your teammates informed of your whereabouts in the even
100. stable following large setpoint changes than the classic quarter wave damping described by Ziegler and Nichols in their 1942 paper Most student built processes are quite safe to operate However if your process harbors any unique hazards e g overflowing water may present a slip hazard overheated oven may cause materials to smoke or burn you must be aware of these hazards and limit everyones exposure to them All team members for each process must be familiar with the inherent hazards of their process and how to mitigate them One operational step to help avoid problems is to configure the controller for setpoint limits preventing the setpoint value from being placed at dangerous values in automatic mode Just what these setpoint limit values should be set to varies with the process and the team s experience operating it As your time with the process builds you will no doubt arrive at ideas for improving it Feel free to work with your team to optimize the process in any way you see fit The goal is to have your process as robust and problem free as possible for other teams to use it in later coursework After you have built and tuned your process you should identify and configure alarm values for the controller s PV display Most controllers have PV alarm capability built in signaling a condition of excessive or insufficient PV if those alarm points are ever tripped You need to set at least a high alarm on the PV so tha
101. subject to master without a doubt An essential component of any course of study in PID control is adequate experimental time spent operating and tuning real PID controlled processes In this course one of the ways you will gain hands on experience with PID control is to operate a miniature process that easily fits on a desktop A simple diagram of this Desktop Process is shown here where a single loop controller controls the speed of a DC electric motor Controller To source of power Variable speed drive VSD Motor command signal VN Hwo wie cable W Shaft coupling Two wire cable lt Motor speed signal The motor receives its power from the Variable Speed Drive VSD and reports shaft speed to the controller by means of a tachogenerator tach which generates a DC voltage proportional to shaft speed Determine the necessary action of the loop controller direct or reverse assuming that a greater current signal sent to the motor drive causes the motor to spin faster Suggestions for Socratic discussion e If you do not have access to a Desktop Process you may gain valuable experience tuning PID loops by using computer simulation software Try searching the internet for free PID simulation programs or web based simulations you can run using a web browser A popular and free PID simulator program is made by Dex Automation file 104257 40 Question 24
102. sure loop current in the circuit connecting the pressure transmitter to the pressure controller There your multimeter registers 15 7 milliamps Identify the likelihood of each specified fault for this control system Consider each fault one at a time i e no coincidental faults determining whether or not each fault could independently account for all measurements and symptoms in this circuit Fault Possible Impossible PT out of calibration outputting wrong current PIC input out of calibration not interpreting PV signal properly PIC output out of calibration not sending correct mA signal to I P Pressure gauge out of calibration not displaying pressure properly I P out of calibration not outputting correct pressure Control valve is oversized Control valve is undersized PIC is poorly tuned not making good control decisions Instrument air supply not at full pressure file 103284 66 Question 83 Sketch the wire connections necessary to interface an electronic sourcing proximity switch to sinking discrete input channel 2 on the process controller and also the I P transducer to analog output 1 Process controller rear view Blk Blu 2 I P transducer file 102453 67 Question 84 Suppose you have recently installed a pressure transmitter ranged from 40 to 240 PSI complete with a field mounted analog loop indicator registerin
103. t for thorough correct answers half credit for partially correct answers and zero credit for major conceptual errors All lab questions must be answered by the due date of the lab exercise Extra credit opportunities exist for each course and may be assigned to students upon request The student and the instructor will first review the student s performance on feedback questions homework exams and any other relevant indicators in order to identify areas of conceptual or practical weakness Then both will work together to select an appropriate extra credit activity focusing on those identified weaknesses for the purpose of strengthening the student s competence A due date will be assigned typically two weeks following the request which must be honored in order for any credit to be earned from the activity Extra credit may be denied at the instructor s discretion if the student has not invested the necessary preparatory effort to perform well e g lack of preparation for daily class sessions poor attendance no feedback questions submitted etc REQUIRED STUDENT SUPPLIES AND MATERIALS Course worksheets available for download in PDF format Lessons in Industrial Instrumentation textbook available for download in PDF format Access worksheets and book at http www ibiblio org kuphaldt socratic sinst e Spiral bound notebook for reading annotation homework documentation and note taking e Instrumentation reference CD ROM fre
104. t when other teams come after you to re tune your process they have some guidepost showing them what PV value s they should not exceed If your team has enough time feel free to connect an actual alarm indicator light and or audible buzzer to your control system that turns on and latches if an alarm point is exceeded A tendency of students when they first learn to tune PID control loops is to proceed carelessly because they know the toy processes they are learning to tune aren t going to harm anything if their PVs go out of bounds While this assumption might be true for your team s process it is not good to form or reinforce bad habits Thus the inclusion of alarm point s on your process PV especially if connected to some form of signaling device that is annoying and or embarrassing to trip such as a loud buzzer makes for a better teaching tool for others learning PID tuning 84 Troubleshooting PID controlled processes It is quite likely during the testing and operation of your control loop that problems will develop The following advice is given to assist you in your diagnostic efforts to quickly identify which portion s of your control loop might be at fault Recall that every feedback control loop consists of four basic elements an element that senses the process variable e g primary sensing element transmitter an element that decides what how to regulate this process variable e g a PID controller an
105. t you must step away from the lab or will be absent for any reason Any student regularly compromising team performance through lack of participation absence tardiness disrespect or other disruptive behavior s will be removed from the team and required to complete all labwork individually for the remainder of the quarter The same is true for students found relying on teammates to do their work for them Cooperation The structure of these courses naturally lends itself to cooperation between students Working together students significantly impact each others learning You are expected to take this role seriously offering real help when needed and not absolving classmates of their responsibility to think for themselves or to do their own work Solving problems for classmates and or explaining to them what they can easily read on their own is unacceptable because these actions circumvent learning The best form of help you can give to your struggling classmates is to share with them your tips on independent learning and problem solving for example asking questions leading to solutions rather than simply providing solutions for them Grades Employers prize trustworthy hard working knowledgeable resourceful problem solvers The grade you receive in any course is but a partial measure of these traits What matters most are the traits themselves which is why your instructor maintains detailed student records including individual exam scores at
106. t you need to do is adjust the process to learn how it responds is it an integrating process a self regulating process or a runaway process Is there significant dead time or hysteresis Is the response linear and consistent Many process control problems are caused by factors other than the controller and this manual test step is a key diagnostic technique for assessing these other factors Step 4 Set the PID constants to minimal settings and switch to automatic mode This means gain less than 1 no integral action 0 rep min or maximum min rep no derivative action and no filtering i e damping Step 5 Bump the setpoint and watch the controller s response This tests the controller s ability to manage the process on its own What you want is a response that is reasonably fast without overshooting or undershooting too much and without undue cycling The nature of the process and the constraints of quality standards will dictate what is too much response time over undershoot and cycling Step 6 Increase or decrease the control action aggressiveness according to the results of Step 5 Step 7 Repeat steps 5 and 6 for P I and D one at a time in that order In other words tune the controller first to act as a P only controller then add integral PI control then derivative PID each as needed 86 Step 8 Bump a load in the process and watch the controller s response This tests
107. tation lab is set up to facilitate the construction of working instrument loops with over a dozen junction boxes pre pulled signal cables and racks set up with 2 inch vertical pipes for mounting instruments These racks also provide structure for building physical processes with more than enough weight bearing capacity to hold any process vessels and equipment The only wires you should need to install to build a working system are those connecting the field instrument to the nearest junction box and then small jumper cables connecting different pre installed cables together within intermediate junction boxes After getting your prototype sketch approved by the instructor you are cleared to begin building your system Instruments attach to 2 inch pipes using special brackets and U bolts These brackets and U bolts are located in the instrument storage area Select a specific loop controller for your system Your instructor may choose the controller for your team to ensure you learn more than one type of controller during the course of a quarter Finally your process control system needs to have a loop number so all instruments may be properly labeled This loop number needs to be unique so that another team does not label their instruments and cables the same as yours One way to make your loop number unique is to use the equivalent resistor color code value for your team s color in the loop number For example if you are the
108. tendance tardiness and behavioral comments and will share these records with employers if you have signed the FERPA release form You are welcome to see your records at any time and to compare calculated grades with your own records i e the grade spreadsheet available to all students You should expect employers to scrutinize your records on attendance and character and also challenge you with technical questions when considering you for employment Representation You are an ambassador for this program Your actions whether on tours during a jobshadow or internship or while employed can open or shut doors of opportunity for other students Most of the job opportunities open to you as a BTC graduate were earned by the good work of previous graduates and as such you owe them a debt of gratitude Future graduates depend on you to do the same Responsibility For Actions If you lose or damage college property e g lab equipment you must find repair or help replace it If you represent BTC poorly to employers e g during a tour or an internship you must make amends The general rule here is this If you break it you fix it Non negotiable terms disciplinary action up to and including immediate failure of a course will result from academic dishonesty e g cheating plagiarism willful safety violations theft harassment intoxication destruction of property or willful disruption of the learning work environment Such
109. ter with be a TT the control valve will be a TV the controller with be a TC etc When your entire team is finished drafting your individual loop diagrams call the instructor to do an inspection of the loop Here the instructor will have students take turns going through the entire loop with the other students checking their diagrams for errors and omissions along the way During this time the instructor will also inspect the quality of the installation identifying problems such as frayed wires improperly crimped terminals poor cable routing missing labels lack of wire duct covers etc The team must correct all identified errors in order to receive credit for their system After successfully passing the inspection each team member needs to place their loop diagram in the diagram holder located in the middle of the lab behind the main control panel When it comes time to troubleshoot another team s system this is where you will go to find a loop diagram for that system The P amp ID s will be submitted to the instructor for inspection as well but the process itself need not be inspected again Common mistakes Forgetting to label all signal wires see example loop diagrams Forgetting to label all field instruments with their own tag names e g PT 83 Forgetting to note all wire colors Forgetting to put your name on the loop diagram Using non standard tags for instruments rather than ISA 5 1 standard notation Basing your d
110. timal gain setting for your process resulting in swift response and minimum offset without too much oscillation Suggestions for Socratic discussion e Generalizing to all proportional controllers explain the effect of decreasing the controller gain value further and further e Generalizing to all proportional controllers explain the effect of increasing the controller gain value further and further file 104263 41 Question 25 Desktop Process exercise Configure the controller as follows e Control action reverse e Gain one tenth the value yielding optimal control ten times the proportional band value yielding optimal control e Reset Integral 1 minute repeat 1 repeat minute e Rate Derivative minimum effect 0 minutes Use the controller s manual mode to establish the process variable at approximately 50 then switch to automatic mode Make a sudden setpoint adjustment at least 10 in either direction and observe the controller s slow integral action response to this change Try increasing the aggressiveness of the integral action i e more repeats per minute or fewer minutes per repeat until a more satisfactory control response is seen from the controller Without adjusting the controller s gain proportional action experiment with different integral settings until good control response is seen with large setpoint changes Your goal is to achieve a quality of contr
111. tion arrows written next to each bubble e Text descriptions e Each instrument documented below tag number description etc Calibration input and output ranges given for each instrument as applicable Connection points All terminals and tube junctions properly labeled All terminal blocks properly labeled All junction field boxes shown as distinct sections of the loop diagram and properly labeled All control panels shown as distinct sections of the loop diagram and properly labeled All wire colors shown next to each terminal All terminals on instruments labeled as they appear on the instrument so that anyone reading the diagram will know which instrument terminal each wire goes to e Cables and tubes e Single pair cables or pneumatic tubes going to individual instruments should be labeled with the field instrument tag number e g TT 8 or TY 12 Multi pair cables or pneumatic tube bundles going between junction boxes and or panels need to have unique numbers e g Cable 10 as well as numbers for each pair e g Pair 1 Pair 2 etc e Energy sources e All power source intensities labeled e g 24 VDC 120 VAC 20 PSI e All shutoff points labeled e g Breaker 5 Valve 7 91 G6 Loop Diagram Furnace temperature control Revised by Mason Neilan Field panel Control room panel Process area JB 12 CP 4 TB 15 TB 11 j Wht Blu ble 3 Pr 1 Blu
112. tion shows how the and inputs of an opamp relate to the characteristic equations for direct and reverse acting proportional controllers PV 5 sp 1 Direct acting If process variable increases If process variable increases geeees controller output increases pamant controller output decreases Pv 77 Reverse acting SP 7777 One way to get yourself into this mind set of marking loop controller inputs with and symbols is to completely replace the ISA standard bubble symbols with triangular opamp symbols Try doing this in the following PFD showing the proper direction of action for each controller for the maple syrup evaporator process by the proper orientation of the opamp symbols inverting and noninverting inputs PV versus SP Water vapor out Evaporator ae SP exchanger Concentrated syrup out Liquid pump Syrup in file 104555 Question 14 This water filter level control system uses an ultrasonic level transmitter to sense the level of water in the filter and a controller to drive a motor actuated valve introducing raw water to be filtered Setpoint Influent Vason ZORN Filter Filtering media Effluent Assuming a direct acting level transmitter increasing filter level increasing signal and a signal to open control valve increasing controller output signal wider open v
113. tion that is still technically accurate Write your own questions based on what you read as though you are a teacher preparing to test students comprehension of the subject matter How to effectively problem solve and troubleshoot Study principles not procedures Don t be satisfied with merely knowing how to compute solutions learn why those solutions work In mathematical problem solving this means being able to identify the practical meaning and units of measurement of every intermediate calculation In other words every step of your solution should make logical sense Sketch a diagram to help visualize the problem When building a real system always prototype it on paper and analyze its function before constructing it Identify what it is you need to solve identify all relevant data identify all units of measurement identify any general principles or formulae linking the given information to the solution and then identify any missing pieces to a solution Annotate all diagrams with this data Perform thought experiments to explore the effects of different conditions for theoretical problems When troubleshooting real systems perform diagnostic tests rather than visually inspecting for faults Simplify the problem and solve that simplified problem to identify strategies applicable to the original problem e g change quantitative to qualitative or visa versa substitute easier numerical values
114. tives each with a different set of problems Calculate voltages currents powers and or resistances in a DC series parallel circuit with 100 accuracy mastery Calculate voltages and currents in an ideal AC transformer circuit with 100 accuracy mastery Identify proper controller action for a given process with 100 accuracy mastery Predict the response of a single loop control system to a component fault or process change given pictorial and or schematic illustrations with 100 accuracy mastery Determine proper AI block parameters to range a Fieldbus transmitter for a given application with 100 accuracy mastery Use decibels to calculate power gains and losses with 100 accuracy mastery Calculate instrument input and output values given calibrated ranges with 100 accuracy mastery Identify specific instrument calibration errors zero span linearity hysteresis from data in an As Found table with 100 accuracy mastery Solve for specified variables in algebraic formulae with 100 accuracy mastery Determine the possibility of suggested faults in a simple circuit given measured values voltage current a schematic diagram and reported symptoms with 100 accuracy mastery Sketch proper power and signal connections between individual instruments to fulfill specified control system functions given pictorial and or schematic illustrations of those instruments e Ina t
115. to calibrate the positioner on the level control valve LV 35 made a mistake and the valve position is consistently open 10 more than it should be For example if controller LIC 35 sends a 50 12 mA control signal to the valve the valve stem will settle at a position of 60 open instead Describe in detail the effect this mis calibration will have on the performance of the level control system for the scrubber vessel Suggestions for Socratic discussion e Perform a thought experiment where you put on a pair of shoes with much thicker soles than you are accustomed to before driving a car The extra thickness of your shoes soles results in the accelerator pedal being pressed down further than it would normally be for any given foot position How will this affect your actual driving speed as you attempt to obey the speed limit e Is the scrubber vessel in danger of over or under filling from the valve s mis calibration e Which would be more dangerous or destructive in this process an over filled scrubber or an under filled scrubber e What purpose does a positioner serve on a control valve file 102929 30 Question 8 In this biogas generation system cow manure is used as a feedstock to produce methane gas CH4 which is then used to fuel an engine to turn a generator and make electricity The waste heat from the engine is used to maintain the cascaded digesters reactors R 101 and R 102 at opt
116. transmitter Sterno fired air heat exchanger Miniature steam boiler Note this is an advanced project Air Fuel ratio burner control Note this is an advanced project Servomechanism position control Note this is an advanced project Inverted pendulum balance Note this is a very advanced project 78 Lab Exercise team meeting prototype sketch and instrument selection An important first step in completing this lab exercise is to meet with your instructor as a team to discuss safety concerns team performance and specific roles for team members If you would like to emphasize exposure to certain equipment e g use a particular type of control system certain power tools techniques e g fabrication or tasks to improve your skill set this is the time to make requests of your team so that your learning during this project will be maximized An absolutely essential step in completing this lab exercise is to work together as a team to sketch a prototype diagram showing what you intend to build This usually takes the form of a simple electrical schematic and or loop diagram showing all electrical connections between components as well as any tubing or piping for fluids This prototype sketch need not be exhaustive in detail but it does need to show enough detail for the instructor to determine if all components will be correctly connected for their safe function For example if you intend to connect field devices to a PLC Prog
117. trend graph Some programs exist for free download or streaming simulation on the Internet allowing you to do this from your own personal computer Research some of the available software options and try downloading at least one of them Be sure to bring your portable computer to class with you ideally with the software already installed for today s classroom activities file 104320 Question 33 Desktop Process exercise An important feature in any process controller is something called output tracking This feature eases the transition from Auto mode to Manual mode Using a Desktop Process demonstrate this feature in action Another important feature in any process controller is something called setpoint tracking This feature eases the transition from Manual mode to Auto mode Using a Desktop Process demonstrate this feature in action file 101490 49 Question 34 Question 35 Question 36 Question 37 Question 38 Question 39 Question 40 50 Question 41 Read Section 10 0 of the Siemens model 353 Process Automation Controller user s manual document UM353 1 Revision 11 March 2003 This section entitled Controller and System Test describes how to test a model 353 controller by stepping through a set of exercises designed to explore its major features It also doubles as an excellent exercise for students to use in understanding this
118. ubleshooting e Ifa student fails to properly diagnose the system fault they must attempt as many times as necessary with different scenarios until they do reviewing any mistakes with the instructor after each failed attempt file instructional 14 Distance delivery methods Sometimes the demands of life prevent students from attending college 6 hours per day In such cases there exist alternatives to the normal 8 00 AM to 3 00 PM class lab schedule allowing students to complete coursework in non traditional ways at a distance from the college campus proper For such distance students the same worksheets lab activities exams and academic standards still apply Instead of working in small groups and in teams to complete theory and lab sections though students participating in an alternative fashion must do all the work themselves Participation via teleconferencing video or audio recorded small group sessions and such is encouraged and supported There is no recording of hours attended or tardiness for students participating in this manner The pace of the course is likewise determined by the distance student Experience has shown that it is a benefit for distance students to maintain the same pace as their on campus classmates whenever possible In lieu of small group activities and class discussions comprehension of the theory portion of each course will be ensured by completing and submitting detailed a
119. uch greater voltage such as 240 VAC file 100356 53 Question 43 Read the Siemens model 353 controller application note on Ethernet Peer to Peer Communication With Model 353 and Procidia i pac Controllers document AD353 113 Revision 1 July 2002 then answer the following questions The communication protocol used by model 353 controllers is Modbus TCP IP Explain how this differs from implementations of Modbus you have seen in RS 485 networks Explain how the AIE and AOE function blocks are used in a pair of model 353 controllers to exchange analog signal data between the two Does one controller read data from another controller or does it write data to another controller or can both events take place The Ethernet Function Block section does presents a good example of how the subnet mask is used to identify a range of IP addresses that controllers may communicate between Read the example given and explain in your own words how the subnet mask works Suggestions for Socratic discussion e Explain why communicating variables via Ethernet would be considered an advantage to a single loop controller such as the Siemens model 353 Why not just communicate all process related variables via 4 20 mA analog signals over twisted pair instrument cables e Identify any disadvantages to communicating process data between controllers using Ethernet Can you think of any faults that could really cause control pro
120. y Stanford California 94305 USA The terms and conditions of this license allow for free copying distribution and or modification of all licensed works by the general public Simple explanation of Attribution License The licensor Tony Kuphaldt permits others to copy distribute display and otherwise use this work In return licensees must give the original author s credit For the full license text please visit http creativecommons org licenses by 1 0 on the internet More detailed explanation of Attribution License Under the terms and conditions of the Creative Commons Attribution License you may make freely use make copies and even modify these worksheets and the individual source files comprising them without having to ask me the author and licensor for permission The one thing you must do is properly credit my original authorship Basically this protects my efforts against plagiarism without hindering the end user as would normally be the case under full copyright protection This gives educators a great deal of freedom in how they might adapt my learning materials to their unique needs removing all financial and legal barriers which would normally hinder if not prevent creative use Nothing in the License prohibits the sale of original or adapted materials by others You are free to copy what I have created modify them if you please or not and then sell them at any price Once again the only catch is that you
121. y of incorrect connections Each member on the team should have ready access to this plan ideally possessing their own copy of the plan throughout the construction process Prototype design sketching is a skill and a habit you should cultivate in school and take with you in your new career When selecting field instruments for this lab exercise choose a transmitter suitable for measuring your process variable and likely an I P converter used to convert the controller s 4 20 mA output signal into an air pressure that a control valve may operate on Electronic process controllers are in several locations throughout the lab ready to be used for controlling processes Your instructor will help you select appropriate instruments for the process you have chosen You may also need a data acquisition unit or DAQ to function as a trend recorder When used with a personal computer and connected properly to the loop circuit a DAQ unit will provide graphical displays of loop variables over time Students usually find the connection of a DAQ unit to their loop controller to be the trickiest part of their loop wiring You will need to consult the manufacturer documentation on the DAQ unit as well as the field instruments and controller in order to figure out how to wire them together Even if your process controller already provides trending capability you may find connection of a DAQ unit to your loop circuits a useful exercise because the ability to quickly co

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