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INST 231 (PLC Programming), section 2 Lab PLC-based

1. 1746 08 _ SOLENOID AIR VALVE 0 51 1746 0W16 0 40 Analyze this control program and then explain what each instruction does including the practical function of each timer instruction Also identify all conditions that will shut down this system stopping the blower motor and the oil pump Suggestions for Socratic discussion e Why is the oil pressure switch contact 1 1 4 in line with the LATCH_RUN seal in contact rather than being in line with the other shut down permissive contacts oil level pump vibration etc e Based on the color highlighting shown red what state is the program in e Identify all the normal electrical switch contact statuses for each shutdown switch e g vibration temperature etc based on an examination of the contact instructions in this program file 104592 48 Question 34 Determine what each of the lamps will do in the following circuit when pushbutton A is pressed for 10 seconds and then released Time delay relays are important circuit elements in many applications L o c lt Show your answer by completing this timing diagram For each of the relay contacts shown in this circuit identify whether it would be properly called an on delay or an off delay contact file 102500 49 Question 35 Programming Challenge Reversing motor restart delay A three phase electric mo
2. Calculate the mechanical horsepower output of this motor assuming 91 efficiency and perfect power factor file 102258 58 Question 47 An Allen Bradley SLC 500 PLC is used to control an air compressor using an across the line motor starter All 480 volt power wiring has been omitted for simplicity Slot 0 Slot 1 Slot 2 Slot 3 processor discrete output unused discrete input 120 VAC power High pressure switch PSH Trip 85 PSI rising Low pressure switch PSL Trip 70 PSI falling The system is broken though the compressor refuses to start even though the air tank is empty no air pressure You have no test equipment with you all you have is what you see in the above illustration Identify the likelihood of each specified fault in this system Consider each fault one at a time i e no coincidental faults determining whether or not each fault could independently account for all observations and symptoms in this circuit Fault Possible Impossible Open wire between PSL and IN2 terminal Open wire between PSH and IN7 terminal Open contactor coil Shorted contactor coil PSL stuck as though P gt 70 PSI PSH stuck as though P gt 85 PSI Failed input card Failed output card PLC program halted Blown fuse file 102254 59 Question 48 Determine all component voltages and currents in this ci
3. Question 6 Calculate all voltages currents and total power in this balanced Y Y system 2100 4160 V phase e Eine Nine 9 E Iphase source 9 Ephase load Iphase load Protal Suggestions for Socratic discussion e Explain how you may double check your quantitative answer s with a high degree of confidence i e something more rigorous than simply re working the problem again in the same way e Identify the effects on these voltage and current values if one of the load resistors fails open file 102435 27 Question 7 Demonstration Program timer instructions An important technique for learning any programming language Ladder Diagram PLC programming included is to write simple demonstration programs showcasing and explaining how particular instructions and programming constructs are supposed to work Since you have access to your own personal PLC you can explore the elements of your PLC s programming language like a scientist would explore new specimens subject them to tests and record how they respond This is how you will be able to teach yourself new models of PLC when you are working in your career when you won t have textbooks to follow or training to show you exactly what to do Write such a demonstration program for your PLC s timer instructions where discrete inputs on your PLC control di
4. 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 troubleshooting e If a 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
5. one 1 input bit state is caused by real electrical power applied to that PLC input channel This means both inputs must be energized by pressure switches that are closed Since pressure switch A is experiencing a pressure of only 14 PSI below the trip threshold of 25 PSI it must be in its resting state Thus we must wire its normally closed NC contact to channel I 0 3 of the PLC Since pressure switch B is experiencing a pressure of 70 PSI above the trip threshold of 55 PSI it must be in its actuated state Thus we must wire its normally open NO contact to channel I 0 1 of the PLC 22 Ca Ca C C C PAVESE Vo V1 V2 DC 1 4 1 5 L j 1 1 DC OUT rie 25 Psi ove E Run Pressure A Fault Force 85 264 VAC 1 VAC G O0 Ol 98 ooooooooooooodo 55 PSI Answer 11 Answer 12 Answer 13 Answer 14 76 Answer 15 Answer 16 Answer 17 Answer 18 Answer 19 Answer 20 Answer 21 Answer 22 Pressure A is greater than 25 PSI Pressure B is greater than 55 PSI Both inputs are sinking current from the switches Answer 23 Answer 24 Answer 25 Although starting all three conveyor motors simultaneously would be very simple it would be
6. Ad 91420 1 plougjos du jeuiqeo 014 file 101880 73 Answers Answer 1 Answer 2 Answer 3 Answer 4 Here is a schematic diagram to help you formulate an answer PLC discrete output Motor drive discrete input Answer 5 Answer 6 Etine 7205 V Itine 19 81 A Ephase source 4160 V Iphase source 19 81A 1 4160 1 19 81 Protal 247 2 kW Answer 7 There are no answers provided here For help consult the instruction set reference manual for your PLC which will describe in detail how each type of instruction is supposed to function in your PLC 74 Answer 8 Output 0 3 4 will activate to energize lamp Y but the other output and lamp will remain off 2 0 1 1 6 1 Answer 9 Both the lamp and the solenoid coil will be energized 1 2 0 1 I 2 4 0 1 2 6 1 75 Answer 10 Color in the online program display reveals path for virtual power in the ladder logic circuit This means every colored contact is in its closed state while every uncolored contact is in its open state Since we see that only the normally open contact instructions are colored while all the normally closed contact instructions are uncolored we know that all bit states must be one 1 A
7. PLC controlling an AC induction motor though a contactor The motor s 480 VAC three phase wiring and the power sources have been eliminated from this diagram for simplicity Start Stop NO NC CLICK Koyo RUN EN ERR PORT 1 TX Rx1 TX2 LI RX2 PORT 2 Contactor 3 RS 485 O 2 e RX3 LG 0 24V Q 24 VDC power 120 VAC power Unfortunately the motor is not starting up when it should You are summoned to investigate so you connect a laptop PC to the PLC to examine the live status of the program elements X1 X2 Yl Based your examination of this program identify some likely faults to explain why the motor is not starting and describe your next diagnostic step s in isolating the exact nature and location of the problem Also determine whether the Y1 output is sourcing or sinking current file 102268 37 Question 24 Suppose an Allen Bradley PLC controls the starting and stopping of a conveyor belt using a timer to sound an audible warning siren for 5 seconds before the conveyor belt starts up to warn people before the belt begins to move START_SWITCH I 1 4 STOP SWITCH 172 PULL CABLE I 1 0 ENABLE B3 0 0 T4 1 DN ENABLE B3 0 0 ENABLE B3 0 0 T4 1 DN gt Timer Time Base Preset Accum TON Timer On Delay T4
8. The purpose of this review session is to see multiple solutions to one problem explore different programming techniques and gain experience interpreting PLC programs others have written When presenting your program either individually or as a team prepare to discuss the following points e Identify the tag names or nicknames used within your program to label I O and other bits in memory e Follow the sequence of operation in your program simulating the system in action e Identify any special or otherwise non standard instructions used in your program and explain why you decided to take that approach e Show the comments placed in your program to help explain how and why it works e How you designed the program i e what steps you took to go from a concept to a working program file 104657 44 Question 29 Suppose you need to connect three pressure switches to channels IN 4 IN 6 and IN 13 of an Allen Bradley model 1756 IA16 discrete input card 1756 1A16 2 IN 4 IN 6 120 Needs to energize input IN 4 when switch detects low pressure Needs to energize input IN 6 when switch detects low pressure IN 8 IN 10 IN 12 IN 14 121 Needs to energize input IN 13 when switch detects high pressure Sketch the necessary wire connections to make these three pressure switches functional on the specified input channels including any necessary power source s in your sketched
9. A PLC is used to control the opening and closing of a solenoid operated valve with a single discrete output A pair of normally open limit switches sense the valve s stem position Compressed air supply 1 Alarm lam Full open limit Valve Write a PLC program energizing an alarm lamp if the valve fails to reach the full open position within 5 seconds of receiving the open command signal and energizing the same alarm lamp if the valve fails to reach the full closed position within 8 seconds of receiving the close command signal Note that the status of both limit switches will be open off when the stem is between its full open and full closed positions The PLC receives the command to open or close the valve from a hand operated toggle switch Inputs e Open Close toggle off when commanding valve to shut on when commanding valve to open wide e Valve closed limit NO closes when valve reaches 0 position e Valve open limit NO closes when valve reaches 100 position Outputs e Valve actuator solenoid energizing this coil opens up the valve de energizing this coil allows the valve to spring return shut e Valve stuck alarm lamp energize if valve does not respond in time When your program is complete and tested capture a screen shot of it as it appears on your computer and prepare to present your program solution to the class in a review session for everyone to see and critique
10. L2 and L3 on the motor drive The LED indicator for output 0 on the PLC card is lit 24 revealing that the PLC program at least is trying to activate the motor drive This data suggests but does not guarantee that the problem lies either with the PLC hardware or the drive and not with the power sources motor wiring motor PLC inputs or PLC program Both the PLC and the motor drive are complex programmable devices The technician knows she could spend quite a bit of time diagnosing either of these devices trying to find a problem Thus it would be very helpful to know which of these devices is at fault so as to not waste troubleshooting time Devise a simple test for the technician to perform that will neatly divide the problem in half telling her whether the PLC or the drive is at fault and be sure to explain your reasoning Suggestions for Socratic discussion e Is the PLC output card sourcing curren to or sinking current from the VFD in this system e If the problem lies within the PLC where exactly do you think it might be found within the PLC Do you think it could be a hardware problem a software problem or either file 102451 25 Question 5 An Allen Bradley SLC 500 PLC is used to control a motor using an across the line starter All 480 volt power wiring in this PLC controlled bucket has been omitted for simplicity Slot 0 Slot 1 Slot 2 Slot 3 processor discrete output unused discrete
11. and a motor contactor for a pump as shown in this illustration Slot 0 Slot 1 Slot 2 Slot 3 processor discrete output unused discrete input 120 VAC power Explain what conditions must be met for the pump to turn on based on an analysis of the program running in the PLC I 3 4 TON Timer On Delay T4 3 0 1 250 Time Base Preset Suggestions for Socratic discussion e What condition s will cause the EN bit in timer T4 3 to activate 4T file 104634 How will this system behave if the contactor coil fails open How will this system behave if the contactor coil fails shorted How will this system behave if the level switch fails open How will this system behave if the wire connecting L1 to the VAC 1 terminal fails open How will this system behave if the wire connecting L2 N to the COM terminals fails open Question 33 An Allen Bradley SLC 500 controls the start up and shut down of a large air blower fan with a pressurized lubrication oil sub system to keep the blower bearings lubricated as they turn 0000 0001 0002 0003 0004 u J 1746 IB16 ET 10 1746 IB16 B3 10 1746 IB16 1746 1816 1746 1816 1746 1816 1746 1816 JE B3 10 1746 IB16 1746 IB16 J 1746 1816 T4 DN B3 10
12. work environment Such offenses are grounds for immediate termination in this career and as such will not be tolerated here file expectations 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 using 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 All
13. 1 0 1 50 ENABLE B3 0 0 CONTACTOR 0 3 0 SIREN 02315 DN Determine the necessary contact connections form A or form B on the real life Start Stop and emergency Pull Cable switches to complement the virtual contact types in the PLC program Start switch form A or form B Stop switch form A or form B Pull Cable switch form A or form B Suggestions for Socratic discussion e How could you modify this program so that the operator has to hold the Start pushbutton switch actuated for the duration of the warning siren before the motor would start i e everything would simply stop if the operator only momentarily pressed the Start button e Suppose a technician decides to use the force utility in the PLC to force bit B3 0 0 to 0 state in order to test the warning siren s operation without actually starting up the conveyor belt Explain what is flawed with this testing strategy and identify a better approach e How will this system behave if the pull cable switch fails open e How will this system behave if the stop switch fails shorted file 102259 38 Question 25 A gravel crushing operation uses three long conveyor belts to move rock from the quarry to the crusher The belts must be started up in a particular sequence to avoid overloading the electric motors driving them Conveyor A Conveyor B Conveyor C Rock from quarr q y T T T Pei R
14. a bad thing to do because of the inrush current of all three motors placing undue load on the power system Answer 26 Input switch electrical normal statuses e Start NO e Stop NC e PSL NC e PSH NC e Reset NO Answer 27 Partial answer Eune 277 Tine 0 133 Iphase load 0 133 A Answer 28 TT Answer 29 Needs to energize input IN 4 when switch detects low pressure 1756 1A16 Needs to energize input li when switch detects low IN 8 IN 10 IN 12 IN 14 Needs to energize input IN 13 when switch detects high pressure L1 120 VAC source Answer 30 The purpose of the parallel connected 14 3 resistor is to provide a path for current to each connected channel of the input card even when the discrete switch is in the open state The card has two optocoupling devices per channel one for detecting this leakage current and another for detecting the full on current when the switch closes Thus the card has the ability to monitor wiring continuity even when the field switch device is in the off state The leakage current range necessary for diagnostic monitoring of input wiring is between 1 2 mA and 1 5 mA inclusive In order for the card to detect a full on condition the current must lie within the range of 2 mA 10 VDC to 13 mA 30 VDC Answer 31 Necessary conditions to start the pump e Pressure must be less than 20 PSI for at
15. 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 answers 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 facilit
16. circuit Note you may find Allen Bradley s document called 1756 ControlLogix I O Modules publication 1756 TD002A EN E May 2009 helpful in answering this question file 102060 Question 30 The Allen Bradley Logix5000 family of PLCs has the option of a model 1756 IB16D DC diagnostic input card where each discrete input device switch is supposed to be wired such that it has a 14 3 resistor connected in parallel with it Examine the internal schematic for a typical channel on this input card as well as the sample wiring diagram showing how switches are supposed to be connected to the inputs of this card and identify how this card provides diagnostic information above and beyond the basic recognition of switch status Note you may find Allen Bradley s document called 1756 ControlLogiz I O Modules publication 1756 TD002A EN E May 2009 helpful in answering this question file 102039 45 Question 31 Suppose we have Allen Bradley model SLC 500 PLC connected to switches and a pump contactor as shown in this illustration Slot 0 Slot 1 Slot 2 Slot 3 processor discrete output unused discrete input 120 VAC power Left Right I 3 TON Timer On Delay EN 1 Timer T4 3 DN Time Base 1 0 Preset 17 Accum file 104635 46 Question 32 Suppose we have an Allen Bradley model SLC 500 PLC connected to a liquid level switch a selector switch
17. connected to the PLC and all relevant variables must be named there as well A reasonable approach to developing a robust program prototype is to create your prototype in your own personal brick PLC de bugging it there with all the switches in place to simulate input signals Even if your personal PLC is a different model or manufacture than the project PLC this is a very helpful exercise Furthermore it allows you to continue program development outside of school when you do not have access to the project PLC Only after a prototype program is developed should you begin programming the project PLC I recommend the following steps Establish communications between PLC and personal computer PC Connect all I O cards modules to the PLC and get them recognized by the processor Assign tagnames to all relevant variables beginning with I O points Enter a simplified version of the program running to check for bugs Diagnose any program problems Add complexity to the program e g additional features and run to check for bugs Repeat last two steps as often as necessary Add comments to each and every line of the program explaining how it functions The final program should be well documented clean and as simple as possible All members of the team should have a hand in designing the program and everyone must thoroughly understand how it works Common mistakes e Waiting too long after writing the program code to in
18. entire system 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 wiring 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 wiring diagram for that system Common mistakes Forgetting to label all signal wires see example wiring diagrams Forgetting to label all field instruments with their own tag names e g PSL 83 Forgetting to note all wire colors Forgetting to put your name on the wiring diagram Basing your diagram off of a team mate s diagram rather than closely inspecting the system for yourself Creating and inspecting accurate wiring diagrams should take no more than one full lab session 3 hours if the team is working efficiently 69 Lab questions e Wiring connections e Determine correct wire connections between field components and a PLC I O card to create a working PLC input or output circuit based on diagrams of components with terminals labeled Correct
19. 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 credit 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 e Course worksheets available f
20. given Answer 51 Answer 52 Your loop diagram will be validated when the instructor inspects the loop with you and the rest of your team 81
21. 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 working 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
22. in any way e Suppose a technician uses the PLC s force utility to force bit Q0 1 to a 0 state How will this affect the operation of the system Could the consequences of this force be dangerous in any way file 104428 40 Question 26 An Allen Bradley Logix5000 PLC is used to control the starting and stopping of an air compressor based on momentary contact pushbutton switch inputs as well as high and low pressure switches PSH and PSL respectively Analyze this program and explain how it is supposed to work in_start_switch in_stop_switch run_enable lt run_enable in_psl in_psh run_enable out_comp_motor A E out_comp_motor out_comp_motor RTO Retentive Timer On EN Timer run_time DN Time Base 0 001 Preset 3600000 Accum 0 continued on next page 41 continued from previous page run_time dn CTU Count Up CU Counter DN Preset Accum hours dn out_warning_light in_reset_switch hours run time dn run time RES in reset switch In particular answer these following questions e Determine the normal electrical statuses of all switches e g NO or NC connected to the inputs of this PLC based on an examination of the respective contact instructions within the PLC program e Why is is important that a retentive timer instruction be used for the calculation of total run time e What i
23. 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 system should take no more than one full lab session 3 hours if all components are readily available and the team is working efficiently 67 Lab Exercise programming the system Like wiring a control system programming one is best done with thoughtful planning rather than a design as you build approach Each team will work with the instructor to develop a prototype PLC program usually on a whiteboard or on paper Having multiple teams prototype their programs on whiteboards within the same classroom works well to foster peer review of programming where teams analyze and critique other teams programming solutions Your prototype program should completely address the following points Identify all inputs to the PLC giving each one a sensible tagname Identify all signal outputs from the PLC giving each one a sensible tagname Identify all major program functions i e What must this program do Identify all internal variables necessary for these functions giving each one a sensible tagname Identify all system variables necessary for these functions e g real time clock calendar variables The importance of identifying and naming all relevant variables is paramount to clean programming This is especially true when an HMI Human Machine Interface is to be
24. least 17 seconds e Selector switch must be in the left position e Pushbutton must be released unpressed or level more than 3 feet Answer 32 The liquid level must exceed 5 feet in height for at least 25 seconds and the selector switch must be in the right position in order for the pump to turn on 78 Answer 33 The oil pump will start when the Start pushbutton is pressed It will seal in and latch when the oil pressure has reached its minimum value necessitating the operator hold the Start button pressed for some minimum amount of time during the start up procedure The blower delays turning on for 15 seconds this time delay set by timer T4 0 A solenoid operated air valve actuates simultaneously with the blower motor If the Run Stop switch is set to the Stop position the blower and solenoid valve de energize but the oil pump continues to run for 15 seconds post lube controlled by timer T4 1 If any of the emergency shutdown permissives are lost any of the colored contacts in rung 0 both the blower and the oil pump shut off immediately and the solenoid operated valve also returns to its de energized position Shutdown conditions Emergency stop pushbutton Low oil pressure Low oil level High pump vibration High fan vibration High temperature 79 Answer 34 Time scale 1 second mark Each contact with an arrowhead pointed toward the energ
25. on a single day It is essential that your team plans ahead what to accomplish each day 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 63 Lab Exercise team meeting and prototype sketch 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 sk
26. the instructor to 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 incomp
27. timer instruction s current value Sketch a simple ladder diagram program for an Allen Bradley MicroLogix 1000 PLC whereby a switch connected to input I 0 2 causes a timer to increment count up and then turn on an alarm light output 0 0 1 after 5 seconds Suggestions for Socratic discussion e If you have access to your own PLC for experimentation I urge you to write a simple demonstration program in your PLC allowing you to explore the behavior of these PLC instructions The program doesn t have to do anything useful but merely demonstrate what each instruction does First read the appropriate section in your PLC s manual or instruction reference to identify the proper syntax for that instruction e g which types of data it uses what address ranges are appropriate then write the simplest program you can think of to demonstrate that function in isolation Download this program to your PLC then run it and observe how it functions live by noting the color highlighting in your editing program s display and or the numerical values manipulated by each instruction After playing with your demonstration program and observing its behavior write comments for each rung of your program explaining in your own words what each instruction does e Some of the addressing examples given in the Allen Bradley MicroLogix 1000 manual for timer instructions use forward slash characters while other examples use dot characters
28. to delimit the last portion of the address What do these different characters mean in Allen Bradley addressing For example what is the different between T4 0 EN and T4 0 ACC Why must the EN be preceded by a forward slash while the ACC is preceded by a dot file 100247 23 Question 4 A technician is troubleshooting a problem with a newly installed PLC and variable speed motor drive One of the discrete on off outputs of the PLC is connected to a discrete input on the drive to tell the motor to either turn on or turn off The PLC s discrete output is a dry contact type meaning it is nothing more than an electromechanical relay contact inside the output card The discrete inputs on the drive DIO and DI2 are logic gate inputs internally pulled up with resistors so that the only thing needed to activate each input is to form a connection between the respective input and the common Com terminal on the drive The dry contact for PLC output 0 on the right most output card is supposed to do just that telling the drive when to start the motor 3 phase AC power lines To 3 phase motor The problem is the motor does not start when the PLC tells it to Now the motor itself is brand new and the wiring between the motor and the drive is known to be good A power check at the PLC and drive power terminals shows 117 volts AC between L1 and L2 N on the PLC and 482 volts between each of the three phases L1
29. 22 newton 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 1019 ergs erg 778 169 foot pound force ft Ibf 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 2 9979 x 108 meters per second m s 186 281 miles per second mi s Avog
30. INST 231 PLC Programming section 2 Lab PLC based motor control system Question 51 and 52 completed objectives due by the end of day 3 Exam Day 3 only a simple calculator may be used Specific objectives for the mastery exam Electricity Review Calculate voltages currents powers and or resistances in a DC series parallel circuit Sketch proper wire connections for sourcing or sinking PLC I O points Determine status of PLC discrete output given discrete input states and a simple RLL program listing Calculate either the full load current or the horsepower of an electric motor either single or three phase given the line voltage and one of the other parameters Solve for a specified variable in an algebraic formula e Determine the possibility of suggested faults in a simple PLC circuit given a wiring diagram RLL program listing and reported symptoms INST240 Review Calculate ranges for hydrostatic DP level measuring instruments given physical dimensions and fluid densities INST250 Review Convert between different pressure units PSI W C bar etc showing proper mathematical cancellation of units i e the unity fraction technique INST262 Review Identify specific instrument calibration errors zero span linearity hysteresis from data in an As Found table Recommended daily schedule Day 1 Theory session topic Timer instructions Questions 1 through 20 answer questions 1 7 in prepar
31. T 251 5 cr PID Control INST 252 4 cr Loop Tuning amp 161 5 cr Chemistry file sequence 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
32. Vo V1 1 2 DC 1 4 VS COM i i 000000 Power Run Fault Force 0000 r r r r VAG VAG VAG VAG i tN 90 Of 92 OS oooooooooooooQ L DC OUT Trip 3 feet Solenoid coil We wish for the solenoid valve to energize and open when the liquid level in the tank reaches 4 5 feet then de energize and shut when the liquid level falls to 3 feet Write a RLL program for the PLC complete with correct address labels for each of the virtual contacts to fulfill this function file 102257 53 Question 42 Suppose the wire between terminal number 7 and input channel IN5 breaks open in this PLC controlled motor starter system Slot 0 Slot 1 Slot 2 Slot 3 processor discrete output unused discrete input 120 VAC power Determine the effect this fault will have on the system and identify how that fault could be diagnosed using the color highlighted RLL program display in the editing software of a personal computer connected to this PLC file 102378 54 Question 43 Sketch the wires necessary to connect two limit switches normally closed contacts to input channels Ix 5 and Ix 11 of a Siemens SM 321 discrete input card model 6ES7321 1BH50 0A A0 The internal schematic diagram of the first channel Ix 0 is shown as typical for all the channels typical T To interface circuitry 24 VDC Also identi
33. a 1012 Symbol T Giga 109 Symbol 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 2 107 Symbol m Micro 1079 Symbol Nano 1079 Symbol n Pico 107 Symbol Femto 1071 Symbol f Atto 1071 Symbol a Zepto 10 21 Symbol z Yocto 10 24 Symbol METRIC PREFIX SCALE T G M k m tera giga mega kilo none milli micro nano pico 1022 31709 1098 109 109 qst 2039 1059 20 r0 1 054 hecto deca deci centi h da Conversion formulae for temperature F C 9 5 32 C F 32 5 9 R F 459 67 273 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 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 4 448
34. actions 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 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 questionO 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 Way 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 de
35. adley PLCs is best done using a PC with a 9 pin serial port We have found trying to use a USB to serial adapter very troublesome with Allen Bradley software 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 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 evacuat
36. adro s number 6 022 x 1023 per mole 1 Electronic charge 1 602 10 19 Coulomb Boltzmann s constant k 1 38 x 10 23 Joules per Kelvin J K Stefan Boltzmann constant o 5 67 x 10 8 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 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 level 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 10 5 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 Writ
37. als to the system as well as internal variables if possible before commencing on the development of the program itself In order to reinforce this practice your team will be required to develop a complete list of all input and output points on your proposed system along with any tagnames also known as symbols or nicknames identifying the function of each Once this list is complete and you are ready to begin developing the PLC program you can enter all the tagnames and define the I O points as your very first programming step With this data in place the writing of your program will be made easier because each I O tag you reference will already be defined and labeled reminding you of their functions within the system Here is a sample I O list for a motor control PLC program Hardware I O terminal I O type Tagname Notes Card 1 terminal INO 24 VDC discrete input START_PB Black pushbutton momentary NO contacts Card 1 terminal IN1 24 VDC discrete input STOP_PB Red pushbutton momentary NC contacts Card 1 terminal IN2 24 VDC discrete input E_STOP Red pushbutton latching NC contacts Card 2 terminal INO 4 20 mA analog input MTR_TEMP Current signal scaled 0 to 150 deg F Card 3 terminal OUTO 120 VAC discrete output CONTACTOR To terminal Al 66 Lab Exercise wiring the system The Instrumentation lab is set up to facilitate the construction of working systems with over a dozen junc
38. at of a non retentive on delay timer How does each type of timer get reset When a timer instruction is reset does its current value go to zero or one How does each type of timer get to control something like an output bit Is it possible to preload a timer instruction so that it doesn t have to begin at the starting value when the PLC program runs anew What happens to the timer s current value when it reaches its maximum value Does the timer instruction stop timing or does it do something else file 103692 28 Question 8 Suppose we have an Allen Bradley model SLC 500 PLC connected to a pair of momentary contact pushbutton switches and light bulbs as shown in this illustration Slot 0 Slot 1 Slot 2 processor discrete input unused Slot 3 discrete output 120 VAC power Switch A l Switch B L Examine the following relay ladder logic RLL program for this Allen Bradley PLC determining the statuses of the two lamps provided switch A is pressed by a human operator and switch B is unpressed I 4 Suggestions for Socratic discussion e Identify which LED indicators on the I O cards faces would be lit in this condition e Describe how this system would respond if a technician used the force utility to force bit 0 3 4 to a 1 state in the PLC s memory file 103760 29 Question 9 Suppose we have an Allen Bradley model SLC 500 PLC conne
39. ation for discussion remainder for practice Day 2 Theory session topic Timer applications and Review for exam Questions 21 through 40 answer questions 21 28 in preparation for discussion remainder for practice Feedback questions 41 through 50 are optional and may be submitted for review at the end of the day Course Syllabus INSTRUCTOR CONTACT INFORMATION Tony Kuphaldt 360 752 8477 office phone 360 752 7277 fax tony kuphaldt btc ctc edu DEPT COURSE INST 231 CREDITS 3 Lecture Hours 10 Lab Hours 50 Work based Hours 0 COURSE TITLE PLC Programming COURSE DESCRIPTION In this course you will learn how to wire program and configure programmable logic controllers PLCs to perform discrete control functions including combinational logic counters and timers Pre Corequisite course INST 230 Motor Controls Prerequisite course MATH amp 141 Precalculus 1 with a minimum grade of C COURSE OUTCOMES Construct program and efficiently diagnose control systems incorporating programmable logic controllers PLCs COURSE OUTCOME ASSESSMENT PLC wiring programming and configuration 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 with
40. cted to three switches and two loads a lamp and a solenoid coil as shown in this illustration Slot 0 Slot 1 Slot 2 Slot 3 processor discrete output discrete input unused 120 VAC power Solenoid 112 PSI The following is the PLC s program as it appears printed on paper From this information determine the status of the lamp and of the solenoid coil provided a process pressure of 130 PSI a process temperature of 186 F and an unpressed pushbutton switch 1 2 1 2 Orc 6 0 5 I2 4 30 file 104527 Question 10 Choose the appropriate switch terminals to land wires connecting the two pressure switches to the PLC in order to satisfy the requirements of the online program display showing color highlighting assuming pressure A is 14 PSI and pressure B is 70 PSI DODD 1 4 1 5 25 PSI LE Run Pressure A Fault Force 85 264 2 T r 41 0 2 9 3 D 2 2 ooooooododo 55 PSI Pressure B Online PLC program display file 102882 31 Question 11 Programming Challenge Reaction time measurement Program your PLC to measure a person s reaction time in flipping a switch The PLC should energize a light or simply one of the discrete output indicating LEDs telling the user when to flip an input switch and then t
41. e 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 INST231syllabus 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 of Fall Winter and Spring quarters Prerequisite for all INST24x INST25x and INST26x courses gt Prerequisite for INST206 Offered 19 week of Fall Winter and Spring quarters 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 lik
42. e for homework daily discussions with your instructor and turn this into a journal or even a weblog blog for your own reflection and eventual use as a portfolio to showcase your capabilities to employers e Where exactly are the practice problem worksheets located on the Socratic Instrumentation website file 100999 35 Question 22 Suppose we have an Allen Bradley MicroLogix 1000 PLC with two pressure switches connected to it Qo O O O O O O oO O O O O OO s Vo 1 1 1 2 DC 1 4 1 5 L J COM L L DC OUT Trip 25 PSI E Power Run Pressure A Fault Force r 85 264 1 vac vac Li 12 voc 21 0 2 0 3 220 ooooo0000 55 PSI Determine the applied fluid pressures these switches based on their electrical connections and the status highlighting seen in a live display of the PLC s program 0 1 0 0 0 Also determine whether the PLC inputs in this system are sourcing or sinking current Suggestions for Socratic discussion e Explain how we could use the force utility in the PLC to keep the lamp energized at all times regardless of switch status and why it is very important we disable all of our imposed forces when finished with this task file 102261 36 Question 23 Suppose we have a Koyo CLICK
43. e 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 Suppose we have a PLC connected to two process switches as shown in this illustration 120 VAC line power Com NC Trip 2 25 PSI NO Trip 170 oF ACommon Programming Personal computer display Ladder Diagram program Based on the highlighting you see in the live PLC program display determine as best you can the pressure and temperature stimulating each switch Suggestions for Socratic discussion e Identify which LED indicators on the PLC s face would be lit in this condition file 101879 21 Question 2 Read selected portions of the Siemens SIMATIC 57 200 Programmable Controller System Manual document A5E00307987 04 August 2008 and answer the following
44. e 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 explanation 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
45. ead of blink and the siren will go silent The light turns off as soon as the alarm signal goes back to its safe state A timing diagram shows how this should work Alarm switch Might Warning siren Acknowledge pushbutton Alarm_input Blink Light mM Latch Blink Latch Siren EAM M Acknowledge input Alarm input Latch gt H Latch Take this generic PLC program and enter it into your own PLC assigning appropriate addresses to all instructions and demonstrating its operation Suggestions for Socratic discussion e Does the PLC program as written expect a closed alarm switch contact to trigger the alarm or an open alarm switch contact e If the real world alarm switch contact was a pressure switch wired NC normally closed would this circuit function as a low pressure alarm or as a high pressure alarm e If the real world alarm switch contact was a temperature switch wired NO normally open would this circuit function as a low temperature alarm or as high temperature alarm file 102342 52 Question 38 Question 39 Question 40 Question 41 Suppose we have an Allen Bradley MicroLogix 1000 PLC connected to two liquid level switches installed in the same tank controlling a solenoid valve to empty liquid out of that tank Trip 4 5 feet ooooooooooooodo 24V DC
46. ely 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 INST 251 5 PID Control INST 252 4 Loop Tuning amp 161 5 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 PID Control INST 252 4 cr Loop Tuning amp 161 5 cr Chemistry Mar Jan Winter quarter INST 206 1 cr Job Prep II INST 250 5 cr Final Control Elements INS
47. etch 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 Programmable 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 tho
48. fy whether this is a sinking or a sourcing input card and sketch the directions of all currents through your sketched wires file 102508 55 Question 44 A PLC is used to control the starting and stopping of an air compressor Control circuit schematic Contactor Auto Control switch Trip 87 PSI Neutral Control switch Intake filter Compressor Compressed air Condensate drain valve Relay Ladder Diagram program in PLC Suppose the electrical contact on the control switch trip pressure 87 PSI corrodes such that it cannot form a good connection when it s supposed to close Explain how this will affect the operation of this system and also how you could diagnose the problem by viewing the indicator LEDs on the PLC as well as by monitoring the live contact status in the Ladder Diagram with a laptop computer file 102256 56 Question 45 Analyze this Siemens 87 200 PLC program for controlling a motor and explain what it is supposed to do M0 2 T6 Start Stop Low speed Q0 0 0 2 T6 y High speed 00 1 Include an explanation of the motor contactor wiring based analysis of PLC program M file 102255 57 Question 46 Suppose a technician connects voltmeter and an ammeter to the three phase conductors of an running electric motor as shown in this simplified illustration all control wiring has been omitted for simplicity
49. gnostic 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 STUDENT ASSIGNMENTS REQUIREMENTS All assignments for this course are thoroughly documented in the following course worksheets located at http www ibiblio org kuphaldt socratic sinst index html INST231_sec1 pdf INST231_sec2 pdf EVALUATION AND GRADING STANDARDS out of 100 for the course grade e Completion of all mastery objectives 50 Mastery exam score first attempt 10 Proportional exam score 30 Lab questions 10 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 gt 8396 83 gt B gt 80 80 gt C gt 76 76 gt 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
50. he PLC will measure how long it takes for the person to react to the light and flip the switch Suggestions for Socratic discussion e How can you program the PLC to turn on the signaling light in a way that the person being tested cannot anticipate it e How must you configure the reaction time timer to count in units appropriate for this very quick time delay e What type of timer instruction is best suited for the reaction time timer a retentive or a non retentive timer file 102266 32 Question 12 Programming Challenge Alarm event latch history timers A normally closed NC high pressure sensing switch monitors fluid pressure in a chemical reactor vessel opening its contacts if the pressure exceeds the trip point This triggers an alarm lamp to energize in the control room and this lamp will latch in the on state until an operator resets it even if the high pressure condition clears and goes back to normal This is so the operators will know a high pressure event occurred even if they were not in the control room to see it when it happened A PLC implements this latching function using retentive set and reset coils Pressure_switch_high Alarm_output ts Reset_switch Alarm_output En The system works well but the operators want more If they arrive at the control room to see the alarm light on latched they want to know how long the high pressure condition lasted and als
51. igator 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 bookstore e Earplugs available at bookstore Miscellaneous e Simple scientific calculator non programmable non graphing no conversions 30 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 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 ro
52. in a limited time 3 hours total for each exam session independently perform the following tasks Multiple re tries are allowed on mastery 100 accuracy objectives each with a different set of problems Calculate voltages currents powers and or resistances in a DC series parallel circuit with 100 accuracy mastery Sketch proper wire connections for sourcing or sinking PLC I O points given schematic or pictorial diagrams of the components with 100 accuracy mastery Determine status of a PLC discrete output given input states and a simple RLL program with 100 accuracy mastery Calculate either the full load current or the horsepower of an electric motor either single or three phase given the line voltage and one of the other parameters Solve for specified variables in algebraic formulae with 100 accuracy mastery Determine the possibility of suggested faults in a simple PLC circuit given measured values voltage current a schematic diagram and reported symptoms with 100 accuracy mastery Program a PLC to fulfill a specified control system function e In a team 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 resp
53. input 120 VAC power After many years of trouble free operation the motor refuses to start You have no test equipment with you all you have is what you see in the above illustration with neither pushbutton pressed at the time Identify the likelihood of each specified fault in this system Consider each fault one at a time i e no coincidental faults determining whether or not each fault could independently account for all observations and symptoms in this circuit Fault Possible Impossible Open wire between Start switch and IN6 terminal Open wire between Stop switch and INO terminal Open contactor coil Shorted contactor coil Start switch incorrectly wired Failed input card Failed output card PLC program halted Blown fuse Finally identify the nezt diagnostic test or measurement you would make on this system Explain how the result s of this next test or measurement help further identify the location and or nature of the fault Suggestions for Socratic discussion 26 e Suppose we needed to perform some diagnostic tests on the Start and Stop switch input wiring which required actuating those switches repeatedly but we did not want to actually start up the motor Explain how we could use the force utility in the PLC to accomplish this goal and why it is very important we disable all of our imposed forces when the job is done file 102260
54. ircuit to the PLC so you must get it right This exercise tests your ability to properly interpret the pinout of an electromechanical relay properly wire a PLC output channel to control a relay s coil properly polarize a commutating diode to prevent inductive kickback from damaging the PLC output and use a terminal strip to organize all electrical connections It also tests your ability to program motor start stop logic using either a seal in contact or latching retentive coil instructions PLC oooooooooooooQoQ Terminal strip 000000 e e e fe e fe e Power e e le lel e e le Run Fault Force 0000 Diode 2101010 The following components materials will be available to you assorted ice cube relays with DC rated coils and matching sockets terminal strips 1N400X rectifying diodes lengths of hook up wire You will be expected to supply your own screwdrivers and multimeter for assembling and testing the circuit at your desk Start switch to input Stop switch to input Relay to output PLC program instructor chooses Seal in contact Retentive coils 65 Lab Exercise developing a PLC I O list It is a good idea when programming any computer system to first identify all the input and output sign
55. ized position is an on delay contact whereas each contact with an arrowhead pointed away from the energized position i e toward the normal state is an off delay contact Time delay relays are not the easiest for some students to understand The purpose of this question is to introduce students to the four basic types of time delay relay contacts and their respective behaviors Discuss with your students how the contact symbols make sense arrows on the switch actuators describing direction of delay Note to your students how it is possible to have different types of time delay contacts actuated by the same relay coil Answer 35 Answer 36 Answer 37 Answer 38 Answer 39 Answer 40 Answer 41 This is a graded question no answers or hints given Answer 42 This is a graded question no answers or hints given Answer 43 This is a graded question no answers or hints given 80 Answer 44 This is a graded question no answers or hints given Answer 45 This is a graded question no answers or hints given Answer 46 This is a graded question no answers or hints given Answer 47 This is a graded question no answers or hints given Answer 48 This is a graded question no answers or hints given Answer 49 This is a graded question no answers or hints given Answer 50 This is a graded question no answers or hints
56. lete is unprofessional 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 co
57. ly determine all electrical sources and loads as well as all voltage polarities and current directions in a DC input or output circuit based on diagrams of field components and the PLC s I O card with terminals labeled Commissioning and Documentation Explain what is meant by the term sinking with regard to a PLC input card DC Explain what is meant by the term sourcing with regard to a PLC input card DC Explain what is meant by the term sinking with regard to a PLC output card DC Explain what is meant by the term sourcing with regard to a PLC output card DC Explain what TRIAC PLC output card is and how it differs from DC output cards Explain what a relay PLC output card is and how it differs from sourcing or sinking DC output cards Explain the distinction between online and offline programming modes for PLC Mental math no calculator allowed Convert a binary number into decimal Convert a binary number into hexadecimal Convert a decimal number into binary Convert a hexadecimal number into binary Convert a hexadecimal number into decimal Diagnostics e Examine a PLC program and identify any mistakes in it e 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 Pro
58. ly 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 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 Hands on PLC programming challenges daily worksheet questions specify realistic scenarios requiring students to develop real PLC programs on their PLC trainers to implement the desired control function s 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 dia
59. mentation to identify how to properly wire power and program your team s PLC PLC equipment manuals always provide sample diagrams showing how external components may connect to the I O points Feel free to use these sample diagrams as templates for your prototype sketch This is the most challenging portion of your wiring so be sure to work with your teammates to get this right Planning a functioning system should take no more than a couple of hours if the team is working efficiently and will save you hours of frustration and possible component destruction 64 Lab Exercise circuit design challenge Connect an ice cube relay to one of the outputs on a PLC so that the PLC can control the energization of the relay All electrical connections must be made using a terminal strip no twisted wires crimp splices wire nuts spring clips or alligator clips permitted Program this PLC to implement a motor start stop latching control function In order to ensure your program has not been pre written in your computer prior to this assessment you will be asked to sketch a correct ladder diagram PLC program on paper to implement this function prior to using a computer You must connect commutating diode in parallel with the relay s coil to prevent the phenomenon known as inductive kickback which may otherwise damage the transistor output on a PLC Note that incorrectly connecting this diode will present a short c
60. ndividual exam scores attendance 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
61. ng the PLC Note We have found the Autmoation Direct software works equally well through a 9 pin serial port as through a USB port with converter and is very friendly to use e Small brick PLC and HMI panel Allen Bradley option Ja Rockwell Allen Bradley MicroLogix 1000 model 1761 L10BWA price 85 with student discount at North Coast Electric 6 discrete DC inputs 4 discrete relay outputs or Rockwell Allen Bradley MicroLogix 1100 model 1763 L16BWA price 240 with BTC student discount at North Coast Electric 10 discrete DC inputs 6 discrete DC outputs 2 analog inputs RS 485 communication port 10 Mbit s Ethernet communication port embedded web server for remote monitoring of data points series A or B programmable using free MicroLogix Lite software Rockwell Allen Bradley cable part 1761 2 price 30 with BTC student discount at North Coast Electric Automation Direct C More Micro HMI panel 3 inch EA1 S3ML N price 150 optional Automation Direct C More Micro touch screen HMI panel 3 inch EA1 S3ML price 190 Automation Direct cable part EA MLOGIX CBL price 30 and adapter part EA MG SP1 price z 50 necessary for connecting the C More Micro HMI panel to an Allen Bradley MicroLogix 1000 PLC Automation Direct USB serial adapter and cable part EA MG PGM CBL price 40 necessary for programming the C More Micro HMI panel Note Programming Allen Br
62. nted and edited for cleanliness and good programming form This includes labels aliases or symbolic names for all inputs and outputs and comments for each and every rung of logic explaining the rungs functions Although there will be only one program submitted by each team completion of this objective is individual with each student explaining at least a part of the PLC program to the instructor Objective completion table Performance objective Grading 1 2 3 4 Team Team meeting and prototype sketch do first mastery Circuit design challenge mastery ee Complete I O list mastery Prototype PLC program before programming mastery Final wiring diagram and system inspection mastery Demonstration of working system mastery Final PLC program inspection mastery o Lab question Wiring connections proportional Lab question Commissioning proportional SSS Lab question Mental math proportional S55 Lab question Diagnostics proportional De ce The only proportional scoring in this activity are the lab questions which are answered 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
63. o how long it s been since the reactor pressure returned to normal Add instructions to this PLC program to provide the desired timing functionality Suggestions for Socratic discussion e Explain why the PLC program contact for the high pressure switch is normally closed and how this information alone would be enough for us to determine that the high pressure switch itself had NC contacts e What type of timer instruction is best suited for the event duration timer a retentive or a non retentive timer e How could a counter instruction be added to this PLC program to provide useful functionality file 102265 33 Question 13 This is a pressure alarm circuit designed to energize warning light if the process pressure sensed by the pressure switch ever crosses a certain threshold value To 480 volt AC source Pressure switch To process impulse tube connection First determine if this is a low pressure alarm or a high pressure alarm i e under what type of process pressure condition will the light bulb energize an abnormally low pressure or an abnormally high pressure Next determine the effect of a bad wire connection open fault at terminal 2 of the control relay on the status of the warning light Suggestions for Socratic discussion e Identify how the circuit could be altered to alarm in the opposite condition it does now i e high pressure instead of low pressure or low p
64. o possible faults either one of which could account for the problem and all measured values in this circuit and also identify two circuit elements that could not possibly be to blame i e two things that you know must be functioning properly no matter what else may be faulted other than the 120 volt AC power source on off switch and fuse The circuit elements you identify as either possibly faulted or properly functioning 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 Circuit elements that must be functioning properly 1 2 file 103190 62 Question 51 Lab Exercise introduction Your team s task is to construct a system controlled by a PLC The system you choose to build shall use at minimum discrete input s discrete output s and either counter or timer functions This system will be expanded during the next course to include a three pole contactor so designing the system with this in mind or simply installing the contactor in this exercise will save you time later Project ideas include e Air compressor control with high and low air pressure switches e Water sump pump control with high and low water level switches e Other alternatives Must be pre approved by instructor In addition to functioning properly the PLC program must be fully docume
65. ock to crusher PENNE MA WSO PET ROO SUPERNE 1 1 Start Stop pushbutton pushbutton First determine a start up sequence that makes sense which conveyor belt should start first next and last What might happen if the sequence were reversed Why not simply start all conveyor motors simultaneously 39 This operation uses a Siemens 57 series PLC to control the three conveyor belts Analyze this program and explain how it accomplishes the task of starting up the three conveyors in sequence Start oe Run 10 1 MO 0 I Run MO 0 Run 0 T2 Run Conv_C_motor 0 00 2 gt Conv B motor Q0 1 ELMO Conv A motor Q0 0 EL Lastly determine where you might add a contact instruction for an emergency shutoff safety switch so that all three conveyors stop simultaneously if ever the safety switch is actuated Suggestions for Socratic discussion e How long is the time delay between conveyor start ups How might this time delay be altered if needed e Suppose a warning siren were added to the system sounding for a full 15 seconds before the first conveyor belt starts How would you modify the PLC program to include this additional functionality e Suppose a technician uses the PLC s force utility to force bit T2 to a 0 state How will this affect the operation of the system Could the consequences of this force be dangerous
66. of every intermediate calculation In other words every step of your solution should make logical sense Sketch 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 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 distr
67. onsibilities in completing all labwork Construct and commission a motor start stop system using a PLC as the control element Generate an accurate wiring diagram compliant with industry standards documenting your team s motor control system e Independently perform the following tasks with 100 accuracy mastery Multiple re tries are allowed with different specifications conditions each time Program a start stop function in a PLC and wire it to control an electromechanical relay COURSE OUTLINE A course calendar in electronic 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 INST231 Section 1 PLC contact coil and counter programming 4 days theory and labwork e INST231 Section 2 PLC timer and sequence programming 2 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 continual
68. or download in PDF format e 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 free 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 e Small brick PLC and HMI panel Automation Direct option Automation Direct CLICK PLC model C0 00DD1 D price 70 8 discrete DC inputs 6 discrete DC outputs or Automation Direct CLICK PLC model C0 02DDI D price 130 4 discrete DC inputs 4 discrete DC outputs 2 analog inputs 2 analog outputs RS 485 Modbus communications port real time clock and calendar Automation Direct CLICK 24 VDC power supply model C0 00AC price 30 24 VDC at 0 5 amp maximum output Automation Direct C More Micro HMI panel 3 inch EA1 S3ML N price 150 optional Automation Direct C More Micro touch screen HMI panel 3 inch EA1 S3ML price 190 Automation Direct USB serial adapter and cable part EA MG PGM CBL price 40 necessary for programming the C More Micro HMI panel also works for programmi
69. ou can think of to demonstrate that function in isolation Download this program to your PLC then run it and observe how it functions live by noting the color highlighting in your editing program s display and or the numerical values manipulated by each instruction After playing with your demonstration program and observing its behavior write comments for each rung of your program explaining in your own words what each instruction does e Why do you suppose Siemens designed their timer instructions to update their current values differently depending on the programmed resolution of the timer Why not make all timer instructions update similarly regardless of resolution file 100229 22 Question 3 Read selected portions of the Allen Bradley MicroLogix 1000 Programmable Controllers Bulletin 1761 Controllers user manual document 1761 6 3 July 1998 and answer the following questions Identify the different types of timer instructions available in the MicroLogix 1000 controller explaining how each one functions How do these types compare with those offered in the Siemens 57 200 PLC Identify a practical application for a retentive timer instruction programmed into a PLC How many different options do the Allen Bradley MicroLogix timer instructions provide for resolution How long can one of these timer instructions time up to Based on this maximum value how many bits do you think are used in the register to store a
70. pose a diagnostic test for troubleshooting a failed system and then explain the meanings of two different test results 70 Wiring diagram requirements Wiring diagram Proper symbols and designations used for all components Relay coil and contacts properly named 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 terminal blocks properly labeled All terminals shown in proper order on diagram All I O cards and points fully labeled complete with program addresses All wires are numbered All electrically common points in the circuit shall bear the same wire number wire colors shown next to each terminal Cables and tubes e 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 Energy sources All power source intensities labeled e g 24 VDC 120 VAC 20 PSI e All shutoff points labeled e g Breaker 5 Valve 7 file 103655 Question 52 Wiring diagram requirements Perhaps the most important rule to follow when drafting a wiring diagram is your diagram should be complete and detailed enough that even someone who is not a technician could understand where every wire should connect in the s
71. questions Identify the different types of SIMATIC timer instructions explaining how each one functions Identify practical application for a timer instruction programmed into PLC How long can one of these timer instructions time up to Based on this maximum value how many bits do you think are used in the register to store a timer instruction s current value What is meant by the resolution of a timer instruction How many different options do the SIMATIC instructions provide for resolution Comment on how a SIMATIC timer s value is updated in a PLC program if the resolution is 1 ms if it is 10 ms and if it is 100 ms The Siemens 7 200 PLC handles each one differently Sketch a simple ladder diagram program for a Siemens 7 200 PLC whereby a switch connected to input 10 3 causes a timer to increment count up and then turn on an alarm light output 00 9 after 5 seconds Suggestions for Socratic discussion e If you have access to your own PLC for experimentation I urge you to write a simple demonstration program in your PLC allowing you to explore the behavior of these PLC instructions The program doesn t have to do anything useful but merely demonstrate what each instruction does First read the appropriate section in your PLC s manual or instruction reference to identify the proper syntax for that instruction e g which types of data it uses what address ranges are appropriate then write the simplest program y
72. 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 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 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
73. rcuit being sure to mark directions of all currents conventional flow notation and polarities of all voltages 3k3 Also identify the amount of voltage between points and file 102272 60 Question 49 Suppose a technician needs to test a pair of wires in a newly installed multi pair cable for open and short faults The cable ends are terminated at terminal blocks too far away to permit a multimeter s test leads to stretch from one end to the other I a long distance Shield wire Shield wire O we Devise a series of measurements that a technician could take using a multimeter located at one end of the cable Be sure to specify which setting the multimeter should be configured for and which terminals the test leads should touch Also be sure to specify what range of measurements would indicate good versus bad for each test e Pair A wires shorted together in cable e Either conductor of Pair A being broken open e Either conductor of Pair A shorted to cable shield file 102263 61 Question 50 Something is wrong with this regulated DC power supply circuit The output is supposed 10 0 volts but instead it measures only about 1 volt Power plug 120 12 6 VAC transformer TP4 Using your digital multimeter you measure 10 0 volts between test points TP5 red test lead and TP4 black test lead From this information identify tw
74. ressure instead of high pressure whichever you have determined the circuit to be in its present configuration file 104508 34 Question 14 Question 15 Question 16 Question 17 Question 18 Question 19 Question 20 Question 21 Identify any area s of your study in which you would like to become stronger Examples include technical reading electrical circuit analysis solving particular types of problems time management and or skills applied in the lab Cite specific examples if possible and bring these to your instructor s attention so that together you may target them for improvement As a starting point try consulting the list of topics on the first page of the worksheet for the upcoming mastery exam as well as the General Values and Expectations list near the beginning of the worksheet identifying the habits and qualities necessary for success in this career Next identify practical strategies you will use to strengthen these areas Examples include focusing on specific types of problem solving whenever those types appear in the homework working through practice problems for a particular subject and or coordinating with your lab team to give you more practice on specific skills Suggestions for Socratic discussion e One useful strategy is to maintain a journal of all you ve learned in a course of study Explore ways you could take the work you re already doing to prepar
75. s the significance of the maintenance warning light controlled by this PLC Suggestions for Socratic discussion e Note how all instructions in this Logix5000 PLC program are addressed by tagname rather than by hardware addresses e g I 2 6 0 3 1 How do you suppose the PLC knows which real I O points to associate with which instructions in the program How will this system behave if the reset switch fails shorted How will this system behave if the high pressure switch fails open How will this system behave if the high pressure switch fails shorted How will this system behave if the low pressure switch fails open How will this system behave if the low pressure switch fails shorted file 102346 42 Question 27 Calculate all voltages currents and total power in this balanced Delta Wye system Source 000 1 2 Eine Nine 2 Iphase source 9 1 Iphase load Protal Suggestions for Socratic discussion e Explain how you may double check your quantitative answer s with a high degree of confidence i e something more rigorous than simply re working the problem again in the same way e Identify the effects on these voltage and current values if one of the load resistors fails open file 102430 43 Question 28 Programming Challenge and Comparison solenoid valve control with stuck valve alarm
76. screte outputs on your PLC An acceptable demonstration program must meet these three criteria Simple nothing extra included in the program to detract from the fundamental behavior of the instruction s being explored Complete nothing missing from the program relevant to the fundamental behavior of the instruction s being explored For a timer demonstration program this includes on delay timers off delay timers and retentive timers Clearly documented every rung clearly commented in your own words every variable named Your instructor will challenge you to use this demonstration program to illustrate what you have learned about PLC counter instructions Suggested questions your demonstration program should answer What are the different timer instruction types offered on your PLC What does each one of them do Where in the PLC s memory is each timer storing its data Where in the PLC programming editor can you view the live status of a timer instruction What are the timebase options for timers in your PLC How fast or slow can they time How long of a time period can a timer time What is the maximum count value for a timer When a timer instruction reaches its preset setpoint value does it keep timing or does it stop at that value How does the operation of an off delay timer differ from that of an on delay timer How does the operation of a retentive on delay timer differ from th
77. se 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 way 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 Select a PLC with modular add on I O cards to provide sufficient complexity for the project Monolithic brick PLCs with no add on I O modules are not acceptable for this project An Allen Bradley SLC 500 PLC would be a good choice as well as a Siemens 57 series or AutomationDirect Productivity 3000 You will also need to select appropriate field devices switches pumps etc for your project You are free to use the field devices left over from the relay based motor control lab if you prefer The next step should be finding appropriate documentation for your PLC All PLC manufacturers provide manuals and datasheets for their products online Use this docu
78. sert comments This is best done immediately while everything makes sense and is fresh in your memory e Insufficient commenting only makes sense to the person who did the programming e Students working on portions of the program 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 68 Lab Exercise documenting the system Each student must sketch their own wiring diagram for their team s system following industry standard conventions Sample diagrams for input and output wiring are shown in the next question in this worksheet These wiring diagrams must be comprehensive and detailed showing every connection every cable every terminal block etc The principle to keep in mind here is to make the wiring diagram so complete and unambiguous that anyone can follow it to see what connects to what even someone unfamiliar with industrial instrumentation In industry control systems are often constructed by contract personnel with limited understanding of how the system is supposed to function The associated 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 When your entire team is finished drafting your individual wiring diagrams call the instructor to do an inspection of the system Here the instructor will have students take turns going through the
79. tailed 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 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 th
80. tion 36 Programming Challenge Run time equalizing pump selection control In critical process applications it is common to find two or three pumps where a single pump would be sufficient for normal operation Municipal water distribution and wastewater collection systems often use dual pumps for redundancy one pump can take over for the other in the event of pump failure Dual pumps used for high reliability municipal water pumping Reservoir Pump Pump B A potential problem with dual pumps is that the spare pump may suffer mechanical problems if it sits idle too long and therefore will fail to perform its function as a backup unit should the primary pump fail for any reason One solution to this problem is to choose the next pump to start based on which one has the least amount of accumulated run time hours on it Each time a pump starts the pump to start is the one with the shortest run time value Write a PLC program to take Start and Stop pushbutton switch inputs and control two pumps in this fashion file 100126 51 Question 37 The following PLC program preforms the function of an alarm annunciator where a discrete input signal from an alarm switch e g high temperature alarm first causes a warning light to blink and a siren to audibly pulse until a human operator presses an acknowledge pushbutton If the alarm switch signal is still activated the light will remain on steady inst
81. tion boxes pre pulled signal cables and racks set up with 2 inch vertical pipes for mounting instruments 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 Your team s PLC must be installed in a suitable electrical enclosure with AC power fed to it through a fuse or circuit breaker on the hot conductor only and firmly grounded the ground conductor of the power cord securely fastened to the metal frame of the enclosure and the PLC chassis All I O wiring should be neatly loomed together and or run through wire duct Panduit Power to I O cards must be routed through their own fuses so that I O power may be disconnected independently of power to the PLC processor and rack Common mistakes e Neglecting to consult the manufacturer s documentation for field instruments e g how to wire them how to calibrate them e Proceeding with wiring before creating an initial sketch of the circuitry and checking that sketch for errors e Mounting the field instrument s in awkward positions making it difficult to reach connection terminals or to remove covers when installed 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
82. tor drives an air heat exchanger radiative cooler in either direction forward or reverse depending on which way operations personnel wish to blow the warm air During warm weather the preferred direction is up to direct hot air away from process equipment During cold weather the preferred direction is down to provide warmth in the process equipment area to help guard against liquid filled pipes and tubes freezing Radiator core Forward blows air up Fan blade Fan blade Reverse blows air down 3 phase 480 VAC Motor A reversing start stop PLC program is easy enough to write with two momentary contact Start pushbuttons one for Forward one for Reverse and one momentary Stop pushbutton but what we need here is a reversing program that prevents an immediate re start of the motor in the opposite direction following a stop command This is because the fan blades have a lot of inertia and take about 30 seconds to coast to a stop This restart lockout timer will prevent someone from trying to reverse the motor s direction before the fan has had a chance to fully stop Write a PLC program to provide this forward reverse restart lockout functionality Assume the use of normally open NO pushbutton switches for all pushbutton inputs Suggestions for Socratic discussion e What type of timer instruction is best suited for this application an on delay or an off delay timer file 102347 50 Ques
83. ughly 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 critical 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
84. ur whereabouts in the event 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 i
85. urse calendar and assignment 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 10 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 yo
86. y 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 day 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 1024 Symbol Zeta 10 Symbol 7 Exa 1018 Symbol E Peta 1015 Symbol Ter
87. ystem Field device symbols Proper electrical symbols and designations used for all field devices Optional Trip settings written next to each process switch PLC I O cards All terminals labeled even if unused in your system Model number I O type and PLC slot number should be shown for each and every card Connection points All terminals 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 devices labeled as they appear on the device so that anyone reading the diagram will know which device terminal each wire goes to Energy sources All power source intensities labeled e g 24 VDC 120 VAC 480 VAC 3 phase e All shutoff points labeled e g Breaker 5 Valve 7 71 1 D iring Sample Input W A dd Ova 080 n 1015 indui 2510 891 9711 jeuiqeo 014 p FEN yoojg 95 1 8 uonounl Duisu 18 96 941 0L HSd Pie 72 Sample Output Wiring Diagram Lit OWA Oct 90 q SNJ4 02 HVd eIqeo O0c HVd 1015 OVIHL OVA 02 001 indino 8jeJosiq 8VO 9vZl 7 Ad

INST 231 (PLC Programming), section 2 Lab PLC-based

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