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1. SL L 6 3 8 9 W x 3 B OOBHOOOOOOOOD The following components and 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 98 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 signals 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 moto
2. Also determine the status of the lamp connected to the PLC s Y1 output file 102144 70 Question 49 Suppose we have a Koyo CLICK PLC connected to three process switches as shown in this illustration CLICK C0 02DD1 D Koyo Trip 32 PSI PWR D RUN D ERR D RUN Trip 10 inches STOP Trip 99 F PORT 1 Co Rx1 D Tx2 D Rx2 CI PORT 2 PORT 3 RS 485 TX3 2 RX3 CI LG 24 VDC Determine the process conditions i e temperature level and pressure values given the offline display of the ladder logic program shown here knowing that the lamp happens to be energized at the present time mT O H file i02145 71 Question 50 This Koyo CLICK PLC has been programmed to control the starting and stopping of an electric motor including a counter instruction to prevent the motor from being started up more than a specified number of times C0 02DD1 D CLICK Start Program inside PLC Ci x x2 CT1 Y1 pe Sto _ PWR CJ x i RUN CJ ae A e Reset Y PORT 1 Y Oya s i RX O Zi aviv Tx2 ap RX2 AD2V e A a Contactor x Counter CT1 CT1 relay coi i poma reas lee y wp SetPoint loss wolo o ean x3 Current CTD1 Rx3 C Le pnav Daai Reset o 24v 24 VDC Ident
3. 10 2 TI 1 Q0 6 e 10 2 e I0 5 e 11 1 e Q0 1 e Q0 6 file i01873 38 Question 17 Suppose we have a Koyo CLICK PLC connected to three momentary contact pushbutton switches as shown in this illustration CLICK C0 02DD1 D Koyo PWR D RUN D ERR D RUN PORT 1 1 CO RX1 D Tx2 D RX2 D PORT 2 PORT 3 RS 485 1x3 O RX3 Ld LG 24 VDC Determine the switch actuation statuses i e pressed versus released given the live display of the ladder logic program shown here x1 X2 X3 YL Also determine the status of the lamp connected to the PLC s Y1 output file i01874 39 Question 18 Explain the function of this light switching circuit tracing the directions of all currents when the switch closes file i01000 40 Question 19 Some of the following transistor switch circuits are properly configured and some are not Identify which of these circuits will function properly i e turn on the load when the switch closes and which of these circuits are mis wired Circuit 1 Circuit 2 Circuit 3 Circuit 4 file 101002 41 Question 20 Some of the following transistor switch circuits are properly configured and some are not Identify which of these circuits will function properly i e turn on the load when the switch closes and which of these circuits are mis wired Circuit
4. e 11 1 e Q0 1 e Q0 3 Suggestions for Socratic discussion e PLC training expert Ron Beaufort teaches students to think of a normally open PLC program contact instruction as a command to the PLC s processor to Go look for a 1 Conversely he teaches students to think of a normally closed instruction as a command to Go look for a 0 Explain what Mr Beaufort means by these phrases and how this wisdom relates to this particular problem Incidentally Mr Beaufort s excellent instructional videos available freely on YouTube are quite valuable to watch Identify the significance of the labels I and Q for this PLC s bits What do you suppose I signifies What do you suppose Q signifies file 104689 45 Question 24 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 neither switch A nor switch B is pressed by a human operator I I Finally draw color highlighting showing how these contact instructions will appear in an online editor program given the sta
5. e How does your PLC address discrete output bits In other words what is the convention it uses to label these bits and distinguish them from each other e How does the programming software for your PLC provide access to discrete output bit status and the ability to force them e Why would anyone ever wish to force an output bit in a PLC especially if doing so overrides the logic programmed into the PLC PLC comparison e Allen Bradley Logix 5000 forces may be applied to specific tag names by right clicking on the tag in the program listing and selecting the Monitor option Discrete outputs do not have specific output channel tag names as tag names are user defined in the Logix5000 PLC series e Allen Bradley PLC 5 SLC 500 and MicroLogix the Force Files listing typically on the left hand pane of the programming window set lists those data files within the PLC s memory liable to forcing by the user Opening a force file window allows you to view and set the real time status of these bits Discrete outputs are the 0 file addresses e g 0 0 7 0 6 2 etc The letter 0 represents output the first number represents the slot in which the output card is plugged and the last number represents the bit within that data element a 16 bit word corresponding to the output card e Siemens 7 200 the Status Chart window allows the user to custom configure a table showing the real time values of multiple addresses
6. 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 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 recogni
7. 1 60934 kilometer per hour km h 0 44704 meter per second m s 0 868976 knot knot international Conversion equivalencies for mass 1 pound Ibm 0 45359 kilogram kg 0 031081 slugs Conversion equivalencies for force 1 pound force lbf 4 44822 newton N Conversion equivalencies for area 1 acre 43560 square feet ft 4840 square yards yd 4046 86 square meters m Conversion equivalencies for common pressure units either all gauge or all absolute 1 pound per square inch PSI 2 03602 inches of mercury in Hg 27 6799 inches of water in W C 6 894757 kilo pascals kPa 0 06894757 bar 1 bar 100 kilo pascals kPa 14 504 pounds per square inch PSI Conversion equivalencies for absolute pressure units only 1 atmosphere Atm 14 7 pounds per square inch absolute PSIA 101 325 kilo pascals absolute kPaA 1 01325 bar bar 760 millimeters of mercury absolute mmHgA 760 torr torr Conversion equivalencies for energy or work 1 british thermal unit Btu International Table 251 996 calories cal International Table 1055 06 joules J 1055 06 watt seconds W s 0 293071 watt hour W hr 1 05506 x 101 ergs erg 778 169 foot pound force ft lbf Conversion equivalencies for power 1 horsepower hp 550 ft lbf s 745 7 watts W 2544 43 british thermal units per hour Btu hr 0 0760181 boiler horsepower hp boiler Acceleration
8. INST 250 5 cr Final Control Elements INST 251 5 cr PID Control INST 252 4 cr Loop Tuning CHEM amp 161 5 cr Chemistry Mar Jan Winter quarter INST 206 1 cr Job Prep II INST 250 5 cr Final Control Elements INST 251 5 cr PID Control INST 252 4 cr Loop Tuning CHEM amp 161 5 cr Mar Chemistry file sequence 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
9. 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 documented 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 Complete 1 O list mastery Prototype PLC program before programming mastery Final wiring diagram and system inspection mastery Demons
10. 1 Circuit 2 Circuit 3 Circuit 4 l file 101003 42 Question 21 Read and outline the Contacts and Coils subsection of the Ladder Diagram LD Programming section of the Programmable Logic Controllers chapter in your Lessons In Industrial Instrumentation textbook Note the page numbers where important illustrations photographs equations tables and other relevant details are found Prepare to thoughtfully discuss with your instructor and classmates the concepts and examples explored in this reading 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 wri
11. DC output cards Explain the distinction between online and offline programming modes for a 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 Propose a diagnostic test for troubleshooting a failed system and then explain the meanings of two different test results 103 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 All wire colors shown next to each terminal Cab
12. 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 continually placing the student in an active rather than a passive role Independent study daily worksheet questions specify reading assignments problems to solve and experiments to perform in preparation before classroom theory sessions Open note quizzes and work inspections ensure accountability for this essential preparatory work The purpose of this is to convey information and 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
13. Siemens PLC program 77 e Will this system still function properly if the optical sensors are spaced farther apart than the width of a human body Explain why or why not file 100185 78 Question 64 A PLC is used to count the number of cans traveling by on a conveyor belt in a fish canning factory An optical proximity switch detects the passage of each can sending a discrete on off signal to one of the PLC s input channels The PLC then counts the number of pulses to determine the number of cans that have passed by Cable 45 Counter reset One day the canning line operator tells you the PLC has stopped counting even though cans continue to run past the proximity switch as the conveyor belt moves Identify what you would do to begin diagnosing this problem justifying each step you would take Suggestions for Socratic discussion e Identify different areas or components within this system that could possibly be at fault as a prelude to identifying specific diagnostic steps e Are there any ways you could diagnose this problem without the use of test equipment e g multimeter e Explain the significance of the sourcing and sinking labels on the I O cards as well as the proximity switch file 102428 79 Question 65 The manufacturing company you work for installs a PLC control system on its assembly line counting the number of components produced every shift For quite a while t
14. a seal in contact instruction to perform the function of latching the motor on and off Jill s PLC program Bob s PLC program 10 1 Q0 0 10 1 10 4 Q0 0 s Saa 10 4 Q0 0 Q0 0 n Explain how both of these PLC programs function properly to control the starting and stopping of the electric motor Suggestions for Socratic discussion e It is ordinarily a bad thing to assign identical bit addresses to multiple coil instructions in a PLC program With Jill s retentive coil program however this is not only permissible but in fact necessary for its proper operation Explain why this is e A common misconception of students first learning PLC programming is to think that the type of contact instruction used in the PLC program must match the type of switch contact connected to that input e g A N O PLC instruction must go with a N O switch Explain why this is incorrect e Explain how both PLC programs will react if both the start and stop pushbuttons are simultaneously pressed 49 e Alter both PLC programs to be fail safe i e shut the motor off if ever the stop pushbutton switch fails circuit open file i03674 Question 27 Demonstration Program contact and coil instructions An important technique for learning any programming language Ladder Diagram PLC programming included is to write simple demonstration programs showcas
15. and how their operation differs from that of regular coil instructions Answer 22 X1 X2 X3 Yl py X2 X1 e Yi lI 114 Answer 23 e I0 7 e 11 1 1 e Q0 1 0 e Q0 3 1 Answer 24 Neither output will activate to energize either lamp Answer 25 Here are just a couple of possible problems to account for what we are seeing There are definitely more possible faults than what are listed here e Overload contact tripped open e Wire connecting Stop switch to OL contact failed open Answer 26 Answer 27 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 Answer 28 If both switches are pressed switch A will be closed I1 2 1 and switch B will be open 10 7 0 leading to this condition of the program T 7 Q0 1 4 k gt 10 7 11 2 Q0 3 a Neither output will activate resulting in both lamps de energized Answer 29 In order for the lamp to energize virtual coil Y1 must be colored In order to color this coil instruction virtual contact X3 must be colored and either virtual contacts X1 or X2 must be colored Since the X3 contact is NO and both X1 and X2 contacts are NC this requires input X3 to be powered and either input X1 or X2 to be unpowered Thus NO pushbutton C
16. and location of the problem Work backward from a hypothetical solution to a new set of given conditions How to create more time for study Kill your television and video games Seriously these are incredible wastes of time Eliminate distractions e g cell phone internet socializing in your place and time of study Use your in between time productively Don t leave campus for lunch Arrive to school early If you finish your assigned work early begin studying the next day s material Above all cultivate persistence Persistent effort is necessary to master anything non trivial The keys to persistence are 1 having the desire to achieve that mastery and 2 realizing challenges are normal and not an indication of something gone wrong A common error is to equate easy with effective students often believe learning should be easy if everything is done right The truth is that mastery never comes easy file question0O 19 Creative Commons License This worksheet is licensed under the Creative Commons Attribution License version 1 0 To view a copy of this license visit http creativecommons org licenses by 1 0 or send a letter to Creative Commons 559 Nathan Abbott 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 licen
17. announcements and planning a The instructor makes general announcements to all students b The instructor works with team to plan that day s goals making sure each team member has a clear idea of what they should accomplish 2 Teams work on lab unit completion according to recommended schedule First day Select and bench test instrument s One day Connect instrument s into a complete loop One day Each team member drafts their own loop documentation inspection done as a team with instructor One or two days Each team member calibrates configures the instrument s Remaining days up to last Each team member troubleshoots the instrument loop 3 End of practical lab session debriefing where each team reports on their work to the whole class Troubleshooting assessments must meet the following guidelines e Troubleshooting must be performed on a system the student did not build themselves This forces students to rely on another team s documentation rather than their own memory of how the system was built e Each student must individually demonstrate proper troubleshooting technique e Simply finding the fault is not good enough Each student must consistently demonstrate sound reasoning while 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 f
18. 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 programming 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 il Rockwell Allen Bradley MicroLogix 1000 model 1761 L10BWA price 85 with BTC 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 CBL PM02 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 E
19. must be pressed and either NO pushbutton A released or NC pushbutton B pressed e Switch A released or Switch B pressed e Switch C pressed 115 Answer 30 Bit statuses e 1 0 0 0 e 1 0 1 0 e I 0 3 1 Answer 31 Bit statuses e 10 2 0 e 11 1 Answer 32 Bit statuses e 1 1 3 1 e 1 1 5 0 Answer 33 116 Answer 34 Two different program solutions Stop_switch Start_switch Estop_cable_switch Motor_run Motor_run Start_switch Motor_run n Stop_switch Motor_run R Estop_cable_switch 117 Answer 35 Remember that a bipolar transistor requires current through the base emitter junction in order to turn on and thereby let load current pass between collector and emitter Circuit 1 This circuit will work Circuit 2 This circuit is bad Circuit 3 This circuit is bad Circuit 4 This circuit is bad Circuit 6 This circuit is bad Circuit 3 is different from the other bad circuits While the other bad circuits lamps do not energize at all the lamp in circuit 3 energizes weakly when the pushbutton switch is open not actuated This is due to the fact that lamp current will naturally pass through the base collector PN junction as though it were a simple diode regardless of the switch s state Answer 36 Circuits 3 5 and 6 are flawed because the emitter base junctions of their transistors are
20. not completed by their specified deadlines your overall grade for the course will be capped at 70 C grade and you will have one more school day to complete the unfinished objectives Failure to complete those mastery objectives by the end of that extra day except in the case of documented unavoidable emergencies will result in a failing grade F for the course Lab questions are assessed by individual questioning at any date after the respective lab objective mastery has been completed by your team These questions serve to guide your completion of each lab exercise and confirm participation of each individual student Grading is as follows full 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
21. overpowered every time the switch closes Hint draw the respective paths of switch and lamp current for each circuit 118 Answer 37 Contact points 119 Answer 38 V V V NPN ee Switch sinking current Transistor sourcing from transistor current to load mis as PNP Transistor sinking emt from load Switch sourcing current to transistor Follow up question explain why neither of the following transistor circuits will work When the pushbutton switch is actuated the load remains de energized L i 120 Answer 39 V Transistor sinking current from load Switch sourcing current to transistor Follow up question V Switch sinking current from transistor 22 E PNP Transistor sourcing current to load explain why neither of the following transistor circuits will work When the pushbutton switch is actuated the load remains de energized V 3 V T 121 Answer 40 Switch A Switch B Light Bulb Unpressed Unpressed Off Unpressed Pressed Off Pressed Unpressed On Pressed Pressed On Note how Switch B has no effect on the PLC s output status The reason for this is the placement of the two identically addresses coils in the PLC program each rung writes either a 0 or a 1 to the same output bit Qo 1 but only the last rung s state is in effect when the PLC finishes its scan of the program an
22. poor practice in PLC programming Next determine the status of the Pump run output channel given the following bit states Timer 01 1 Level_low 1 Switch_hand 0 OL_contact 0 Sump_wet 0 file i02376 88 Question 84 Sketch the wires necessary to connect two pressure switches and two relay coils to the following Allen Bradley MicroLogix 1000 PLC model 1761 L10BWA with 6 discrete DC inputs either sourcing or sinking and 4 discrete relay contact outputs Be sure to wire the two switches so they source current to the PLC s inputs the low pressure switch to I 2 and the high pressure switch to I 5 normally open contacts on both and wire the relay coils so the PLC sources current to them 0 0 and 0 1 Q Q oav DC IO l v2 3 DC 4 Is L 1 COM com DC OUT L L 000000 PSH T C Power 1 Run Cf Fault C Force wes 0000 TEREA vac vac vac vac Li L2 N t ypg Off ype O vpe 2 ype 28 PSL T Q Q Q file i02379 89 Question 85 Suppose we have an Allen Bradley SLC 500 PLC with a water level switch and a temperature switch we need to connect to it Slot 0 Slot 1 processor discrete input Slot 2 unusea Slot 3 discrete output 120 VAG power Well pump contactor Level control switch Trips 2 feet falling 5 feet rising High temp cutout switch The purpos
23. produce a slower blink using this program T2372 CTU Count Up C520 32767 Counter Preset Accum C5 0 ACC 13 O 1 5 C5 0 DN C5 0 c Explain how this program works to fulfill the function of a frequency divider converting the high speed pulse signal of the proximity switch into a low speed blink for the operator light Suggestions for Socratic discussion e Explain how a frequency divider circuit built out of J K flip flop integrated circuits functions and then describe how this PLC program is similar in principle e Explain how to speed up the blinking rate of the light for any given motor shaft speed 81 file i03838 82 Question 67 Programming Challenge and Comparison Mixer motor auto stop A batch mixing process in a manufacturing facility uses a mixer motor and a large paddlewheel to mix liquid ingredients to make a final product A PLC needs to run this motor for exactly 1500 turns of the paddlewheel and then automatically stop The motor needs to be able to start back up if the Start button is pressed again for the next batch Power cable Sensor cable to PLC Mixing vessel Inputs Start pushbutton momentary NO pushing this button closes the switch to energize the PLC input Stop pushbutton momentary NC pushing this button opens the switch to de energize the PLC input Proximity switch NO one pulse per paddle revolution Outputs Motor cont
24. properly designated sourcing or sinking Suggestions for Socratic discussion e Determine how real input and output devices e g switches solenoid coils would need to be connected to the I O terminals of these modules file 102359 31 Question 10 Have some fun writing simple exploratory or demonstration ladder diagram PLC programs to perform different functions Feel free to explore the following instruction types Contacts and coils Counters up down up down Timers on delay off delay retentive Sequencing instructions Math instructions add subtract multiply divide Identify some realistic applications for PLC programs using counters and timers What sorts of real life processes might benefit from a PLC function where something turns on or off after a definite number of counts applied to the PLC input or after a certain amount of time has passed Note this simple exercise may seem trivial but it holds the key to self instruction on PLC programming Having your very own PLC to work with in the classroom is a tremendously powerful learning tool Whenever you encounter a new programming instruction e g a timer a math instruction etc that you do not yet know how to use you may explore that instruction s properties and behavior by creating a simple program in your PLC with nothing but that instruction Your PLC s User Manual or Instruction Set reference manual will show you the bas
25. sequence of courses you take during the second year depends on when you complete all first year courses and enter the second year Since students enter the second year of Instrumentation at four different times beginnings of Summer Fall Winter and Spring quarters the particular course sequence for any student will likely be different from the course sequence of classmates Some second year courses are only offered in particular quarters with those quarters not having to be in sequence while others are offered three out of the four quarters and must be taken in sequence The following layout shows four typical course sequences for second year Instrumentation students depending on when they first enter the second year of the program Possible course schedules depending on date of entry into 2nd year Beginning in Summer Beginning in Fall Beginning in Winter Beginning in Spring Jan Winter quarter INST 200 1 wk Intro to Instrumentation INST 250 5 cr Final Control Elements INST 251 5 cr PID Control INST 252 4 cr Loop Tuning CHEM amp 161 5 cr Chemistry Jan Winter quarter INST 205 1 cr Job Prep INST 250 5 cr Final Control Elements Mar INST 251 5 cr PID Control INST 252 4 cr Loop Tuning CHEM amp 161 5 cr Jan Winter quarter Mar Chemistry INST 205 1 cr masana Job Prep Graduation Graduation Graduation Graduation
26. shows one of the day s diagnostic question diagrams while students propose diagnostic tests and the instructor tells those students what the test results would be given some imagined virtual fault scenario writing the test results on the board where all can see The students then attempt to identify the nature and location of the fault based on the test results Each student is free to leave the classroom when they have completely worked through all problems and have answered a summary quiz designed to gauge their learning during the theory session If a student finishes ahead of time they are free to leave or may help tutor classmates who need extra help The express goal of this inverted classroom teaching methodology is to help each student cultivate critical thinking and problem solving skills and to sharpen their abilities as independent learners While this approach may be very new to you it is more realistic and beneficial to the type of work done in instrumentation where critical thinking problem solving and independent learning are must have skills 13 Lab In the lab portion of each course students work in teams to install configure document calibrate and troubleshoot 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
27. through 20 answer questions 1 10 in preparation for discussion remainder for practice Day 2 Theory session topic Contact and coil programming Questions 21 through 40 answer questions 21 27 in preparation for discussion remainder for practice Day 3 Theory session topic Counter instructions Questions 41 through 60 answer questions 41 47 in preparation for discussion remainder for practice Day 4 Theory session topic Counter applications Questions 61 through 80 answer questions 61 67 in preparation for discussion remainder for practice Feedback questions 81 through 90 are optional and may be submitted for review at the end of the day 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
28. to the input card e Siemens 7 200 the Status Chart window allows the user to custom configure a table showing the real time values of multiple addresses within the PLC s memory Discrete inputs are the I memory addresses e g 10 1 11 5 etc e Koyo Automation Direct DirectLogic and CLICK the Data View window allows the user to custom configure a table showing the real time values of multiple addresses within the PLC s memory Discrete inputs are the X memory addresses e g X1 X2 etc file 101876 27 Question 6 The most basic type of real world output from a PLC isa discrete on off output Each discrete output channel on a PLC is associated with a single bit in the PLC s memory Use the PLC programming software on your personal computer to connect to your PLC then locate the facility within this software that allows you to monitor the status of your PLC s discrete output bits Use the force utility in the programming software to force different output bits to a 1 status Based on what you see what does a 1 bit status signify and what does a 0 bit status signify Is there any visual indication that bits have been forced from their normal state s in your PLC Note that forcing causes the PLC to output the values you specify whether or not the programming in the PLC wants those bits to have those forced values Suggestions for Socratic discussion
29. turns 1500 is not hard coded into the PLC program but rather resides in some memory location that may be altered without reprogramming the PLC file 103688 83 Question 68 Programming Challenge Hour Minute Second timer Many PLCs provide a range of special contacts to the programmer Among these special contacts is typically one that cycles on and off at a rate of once per second like a 1 Hz clock pulse Research the special contact for this function in your PLC then write a PLC program for an Hour Minute Second timer using three counter instructions one to count seconds 0 to 59 one to count minutes 0 to 59 and one to count hours Suggestions for Socratic discussion e What is the address of the special contact in your PLC for the 1 Hz clock pulse e How do you make three counters count in the correct sequence so that one represents seconds the next minutes and the next hours PLC comparison e Allen Bradley SLC 500 status bit S 4 0 is a free running clock pulse with a period of 20 milliseconds which may be used to clock a counter instruction up to 50 to make a 1 second pulse because 50 times 20 ms 1000 ms 1 second e Siemens 7 200 Special Memory bit SMO 5 is a free running clock pulse with a period of 1 second e Koyo Automation Direct DirectLogic Special relay SP4 is a free running clock pulse with a period of 1 second file 103691 84 Question 69 Que
30. 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 within a limited time 3 hours total for each exam session independently perform the following tasks Multiple re tries are allowed on mastery 100 accuracy 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 fu
31. A MLOGIX CBL price 30 and adapter part EA MG SP1 price 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 Bradley 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 B TCInstrumentation 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 Stan
32. Assume the following input conditions e Pushbutton switch unpressed e Pressure above trip threshold e Selector switch in its right hand position 29 Now analyze the status of this PLC controlled system assuming the same input conditions Note the distinction between the 120 VAC circuitry and the virtual circuit in the blue shaded area representing the program executed by the PLC s microprocessor Li 120VAC I PBNO A Pressure switch PLC input card Selector switch Lett X Right 2 e Pushbutton switch unpressed e Pressure above trip threshold e Selector switch in its right hand position How is the PLC controlled system similar to the hard wired relay control system How is it different file 102605 30 Question 9 Discrete on off I O for PLCs often works on AC alternating current power AC input circuitry usually consists of an optocoupler LED with rectification and a large dropping resistor to allow 120 volt AC operation AC output circuitry usually consists of TRIACs Explain how both of these technologies work DC I O for a PLC generally consists of optocoupled LEDs for inputs and bipolar transistors for outputs Some examples are shown in the following schematics Note carefully the different variations Discrete input module Discrete input module Discrete output module Discrete output module Determine for each of these input and output module types whether they would be
33. C s discrete input bits Actuate the switches connected to your PLC s discrete input channels while watching the status of the respective bits Based on what you see what does a 1 bit status signify and what does a 0 bit status signify Suggestions for Socratic discussion e How does your PLC address discrete input bits In other words what is the convention it uses to label these bits and distinguish them from each other e How does the programming software for your PLC provide access to discrete input bit status PLC comparison e Allen Bradley Logix 5000 the Controller Tags folder typically on the left hand pane of the programming window set lists all the tag names defined for the PLC project allowing you to view the real time status of them all Discrete inputs do not have specific input channel tag names as tag names are user defined in the Logix5000 PLC series e Allen Bradley PLC 5 SLC 500 and MicroLogix the Data Files listing typically on the left hand pane of the programming window set lists all the data files within that PLC s memory Opening a data file window allows you to view the real time status of these data points Discrete inputs are the I file addresses e g 1 0 2 1 3 5 etc The letter I represents input the first number represents the slot in which the input card is plugged and the last number represents the bit within that data element a 16 bit word corresponding
34. Cable 2 80 mA current limited LE LH Voltmeter 1k at room temp HF H First determine the voltage we should read at the voltmeter with the thermistor at or near room temperature Next identify the likelihood of each specified fault for this circuit supposing the voltmeter registers 0 volts with the thermistor at room temperature and a voltage measurement taken between terminals D and F registers 10 volts Consider each fault one at a time i e no coincidental faults determining whether or not each fault could independently account for all measurements and symptoms in this circuit Fault Possible Impossible Thermistor failed open Fixed resistor failed open Wire A D failed open Wire F J failed open Wire E H failed open Thermistor failed shorted Fixed resistor failed shorted Short between terminals G H Short between terminals E F Short between terminals D E file 102924 92 Question 88 Determine all component voltages and currents in this circuit being sure to mark directions of all currents conventional flow notation and polarities of all voltages 2 2 KQ 4 7 KQ file i02525 93 Question 89 Suppose a single phase AC load draws a current of 16 5 amps at 237 volts RMS If the measured power factor of this load is 0 85 calculate the true power P dissipated by the load as well as its apparent power S Be sure to incl
35. I 0 2 when switch A is unpressed released switch B is unpressed released and switch C is pressed file 101865 Question 14 Suppose we have a Siemens S7 200 PLC connected to two process switches as shown in this illustration 24 VDC SIEMENS SIMATIC S7 200 Port 1 C SFIDIAG L J RUN LD stop Port 0 Q Q Q Q Q AM 1L 00 01 0 2 03 04 2M 2 05 06 07 10 A m L oo CPU 224XP QO EJ ET ET ET El El EN EI Qy El El DC DC DC OA PO OH Ge 0 al OMe SAS Gar Ul BS os 6 OOOOO0O000 1000000 IM O08 Of O28 O8 08 06 Of BN iM dal we Us ee sI Ma o 130 F 12 GPM Determine the bit statuses of 10 2 and 11 1 when the temperature switch senses 194 F and the flow switches senses 19 GPM file 101871 36 Question 15 Suppose we have an Allen Bradley SLC 500 PLC connected to two process switches as shown in this illustration Slot 0 Slot 1 Slot 2 Slot 3 processor discrete input discrete input discrete output 120 VAC power 37 PSI 88 F Determine the process conditions necessary to generate the following input bit statuses in the PLC s memory e 1 1 3 1 e 1 1 5 0 file 101872 37 Question 16 Examine this live display of a Siemens S7 300 PLC s program and from this determine all bit statuses represented by the color highlighting in this ladder logic program TA l IO S Q0 1
36. INST 231 PLC Programming section 1 Lab PLC based motor control system Question 91 and 92 completed objectives due by the end of day 2 section 3 Exam Day 3 of next section only a simple calculator may be used Specific objectives for the mastery exam e 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 Introduction to PLCs Questions 1
37. PLC comparison e Allen Bradley Logix 5000 various system values are accessed via GSV Get System Value and SSV Save System Value instructions e Allen Bradley PLC 5 SLC 500 and MicroLogix the Data Files listing typically on the left hand pane of the programming window set shows file number 2 as the Status file in which you will find various system related bits and registers e Siemens 7 200 the Special Memory registers contain various system related bits and registers These are the SM memory addresses e g SMO 1 SMB8 SMW22 etc e Koyo Automation Direct DirectLogic and CLICK the Special registers contain various system related bits and registers These are the SP memory addresses e g SP1 SP2 SP3 etc in the DirectLogic PLC series and the SC and SD memory addresses in the CLICK PLC series file 101878 33 Question 12 Write a PLC program that accepts two discrete input signals from two switches and outputs the following four discrete outputs e Output channel 1 The status of input switch 1 simply repeating input 1 e Output channel 2 The Boolean complement opposite of input switch 1 e Output channel 3 The AND function of switches 1 and 2 e Output channel 4 The OR function of switches 1 and 2 Shown here is a generic RLL listing of such a program Input_switch_1 Output 1 Input_switch_1 Output_2 Input switch Input switch 2 Output 3 m Input_switch_1 Out
38. actor energizing this PLC output starts the mixing motor Write a PLC program performing this function and demonstrate its operation using switches connected to its inputs to simulate the discrete inputs in a real application 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 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 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 Suggestions for Socratic discussion e How can you test your program s basic operation without having to flick a switch 1500 times to simulate the full number of paddle revolutions e Try writing your program so that the number of paddle
39. after the counter has disabled the system from starting Answer 51 Answer 52 Answer 53 Answer 54 Answer 55 Answer 56 123 Answer 57 Answer 58 Answer 59 Answer 60 Answer 61 This is one possible fix for the problem PLC program IN_switch_Start IN_switch_Stop OUT_valve OUT_valve IN_oil_press m Answer 62 Answer 63 Hint the P contact instructions are positive transition instructions activating whenever their respective bits transition from 0 to 1 but returning to an inactive state whenever the bit value holds at either 0 or 1 Answer 64 Answer 65 Answer 66 Hint the contact address C5 0 ACC 13 refers to the 13th bit of the counter s accumulator register which is a 16 bit binary number The 15th bit would be the MSB while the Oth bit is the LSB Answer 67 Answer 68 Answer 69 Answer 70 Answer 71 Answer 72 Answer 73 124 Answer 74 Answer 75 Answer 76 Answer 77 Answer 78 Answer 79 Answer 80 Answer 81 This is a graded question no answers or hints given Answer 82 This is a graded question no answers or hints given Answer 83 This is a graded question no answers or hints given Answer 84 This is a graded question no answers or hints given Answer 85 This is a graded question no answ
40. ake 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 S7 series or an 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 documentation 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 97 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 electric
41. al 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 a 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 circuit 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 Q AAA A OOAOAAAODS n n Terminal strip 000000 2 2 e e e e e e c Power e e e a Run c Fault c Force 0000 Diode
42. and Attendance You are expected to arrive on time and be on task all day just as you would for a job Each student has 12 hours of sick time per quarter applicable to absences not verifiably employment related school related weather related or required by law Each student must confer with the instructor to 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 Instru
43. ansistor sourcing from transistor current to load Switch sourcing current to transistor file 101007 60 Question 39 Choose the right type of bipolar junction transistor for each of these switching applications drawing the correct transistor symbol inside each circle V V Transistor sourcing V 4 current to load Switch sinking current from transistor ee Switch sourcing current Transistor sinking to transistor from load Also explain why resistors are necessary in both these circuits for the transistors to function without being damaged file 101008 61 Question 40 Suppose we have a Siemens S7 200 PLC connected to a pair of momentary contact pushbutton switches and a light bulb as shown in this illustration 24 VDC SIEMENS Q Q SIMATIC im il 00 01 0 2 0 3 0 4 2M 2L 0 5 0 6 0 7 1 0 ven 7 200 L SF DIAG ol 2 eh oh GG By CI RUN CI stop 101 3 2 954 tere AA a aOooooooonooa00 ope 10 3 2 92 4 5 ririr aK CPU 224XP DC DC DC Switch A ale Switch B l Examine the following relay ladder logic RLL program for this Siemens PLC determining the statuses of the two lamps provided both switches are simultaneously pressed by a human operator 10 7 Q0 1 gt T4 2 Q0 1 B E Complete the following truth table showing the status
44. ative which is why your instructor will demand you do for yourself rather than rely on others to do for you Examples include setting up and using your BTC email account to communicate with your instructor s consulting manuals for technical information before asking for help regularly checking the course calendar and 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 equip
45. ble to main office display SIEMENS Q H SIMATIC IM 1l 00 04 02 03 04 2M 2 05 06 07 10 11 J e m L oc 57 200 CPU 224XP e anonooonoooooa00 I SF DIAG Oi A 2S A Be Onion PSDo CI RUN I stop OA 2 4 5 6 7 alll 2 9 5 0100000000 oo00000 1M 0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 2M 1 0 AA 12 1 3 14 15 M L Po Port 0 Drive over pressure switch Key Reset switch Unfortunately there is something wrong with this system Although it worked just fine yesterday today the counter s current value as displayed on the main office computer seems to be stuck at 574 no matter how many more cars drive over the pressure switch and enter the garage Explain how you would go about diagnosing the problem in this system justifying each step you would take Suggestions for Socratic discussion e A useful troubleshooting strategy is to mentally divide this system into three major portions and try to determine which portion the problem lies within 1 the switches and wiring connected to the PLC 2 the PLC itself and 3 the network cable and computer in the main office e How important is the fact that this system worked fine yesterday Does this knowledge help you in your troubleshooting e Are there any LED indicators on the face of the PLC that might be helpful in providing diagnostic data for you to pinp
46. bleshoot Study principles not procedures Don t be satisfied with merely knowing how to compute solutions learn why those solutions work In mathematical problem solving this means being able to identify the practical meaning and units of measurement of every intermediate calculation In other words every step of your solution should make logical sense Sketch a diagram to help visualize the problem When building a real system always prototype it on paper and analyze its function before constructing it Identify what it is you need to solve identify all relevant data identify all units of measurement identify any general principles or formulae linking the given information to the solution and then identify any missing pieces to a solution Annotate all diagrams with this data Perform thought experiments to explore the effects of different conditions for theoretical problems When troubleshooting real systems perform diagnostic tests rather than visually inspecting for faults Simplify the problem and solve that simplified problem to identify strategies applicable to the original problem e g change quantitative to qualitative or visa versa substitute easier numerical values 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
47. bserving its behavior write comments for each rung of your program explaining in your own words what each instruction does file 102245 67 Question 46 Read selected portions of the Allen Bradley Logix5000 Controllers General Instructions reference manual publication 1756 RM0031 EN P January 2007 and answer the following questions Identify the different types of counter instructions offered in the Logix5000 PLC family How high can one of these counter instructions count up to How low can it count down to Based on these values how many bits do you think are used in the register to store a counter instruction s current value Unlike the Siemens S7 family of PLCs the Allen Bradley counter instruction box symbols do not provide a place to connect a reset input How then is it possible to command a counter instruction to reset back to zero Sketch a simple ladder diagram program for an Allen Bradley Logix5000 PLC whereby a high temperature switch input with the tag name High Motor_Temp causes a counter to increment count up every time a motor overheats and then turn on an alarm light output tag name Alarm Lamp when the count reaches a value of 5 Also provide a reset function triggered by a normally open switch contact tag name Alarm_Reset to force the count value back to zero when pressed Suggestions for Socratic discussion e If you have access to your own PLC for experimentation I urge
48. ch team in order they appear on the whiteboard to address these problems 96 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 sketch a prototype diagram showing what you intend to build This usually takes the form of a simple electrical schematic and or loop diagram showing all electrical connections between components as well as any tubing or piping for fluids This prototype sketch need not be exhaustive in detail but it does need to show enough detail for the instructor to determine if all components will be correctly connected for their safe function For example if you intend to connect field devices to a PLC 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 componen
49. cumulated value back to zero 1 0 2 C5 0 Fl n 109 Demonstration program showing an on delay timer instruction in an Allen Bradley MicroLogix PLC The TON instruction is a timer Its Accum value starts at 0 and counts up 1 2 3 4 whenever the input contact is colored When the Accum value reaches 5 the DN coil becomes colored The Time Base value of 1 0 means that each count of the Accum is 1 0 seconds worth of time If make the Time Base something different the timer will count faster T 0 0 TON Timer On Delay T4 0 1 0 Preset 5 EN Timer DN Time Base Accum When the timer T4 0 reaches the done condition the contact T4 0 DN becomes colored passing color to the coil O 0 0 to turn on a light bulb connected to output 0 T4 0 DN O 0 0 r Answer 11 Answer 12 Answer 13 Bit statuses e I 0 0 1 e 1 0 1 0 e 1 0 2 1 Answer 14 Bit statuses e 10 2 1 e 11 1 0 Answer 15 L gt 3 feet P gt 37 PSI and T lt 88 F 110 Answer 16 e 10 2 0 e 10 5 1 e 11 1 lt e Q0 1 1 e Q0 6 0 Answer 17 Switch statuses e Switch released e Switch B pressed e Switch C released The lamp will be energized Answer 18 All currents shown using conventional flow notation 111 Answer 19 Circuit 1 This will work Circuit 2 This will work Circuit3 This circuit i
50. d updates the output registers to actually turn its output channels on or off This is why it is a bad idea to assign the same address to multiple coils in a PLC program the only exception to this rule being when the coils in question are retentive i e Set and Reset or Latch and Unlatch coils in which case complementary coil pairs bearing the same address is proper Regular non retentive coil instructions however will conflict with one another in a PLC program if they bear the same bit address Answer 41 Hint to identify whether an I O point is sourcing or sinking sketch arrows showing the direction of electric current using conventional flow notation where wires connect to the I O channel terminals If the arrow shows current exiting the PLC channel and headed toward an external device then that I O channel is sourcing current to that device If the arrow shows current entering the PLC channel from an external device then that I O channel is sinking current from that device Answer 42 Partial answer e Temperature switch cooler than 150 deg F Answer 43 Answer 44 Each wasteful program uses an output bit as the intermediary bit between the AND and NOT functions when there is no need Answer 45 Partial answer Each of the S7 200 counter instructions can count as high as 32767 and as low as 32768 This equates to 16 bits signed integer 2 s complement notation where
51. dard is a simplified clone of AutoCAD and is freely available at http www cadstd com CAMPUS EMERGENCIES If an emergency arises your instructor may inform you of actions to follow You are responsible for knowing emergency evacuation routes from your classroom If police or university officials order you to evacuate do so calmly and assist those needing help You may receive emergency information alerts via the building enunciation system text message email or BTC s webpage http www btc ctc edu Facebook or Twitter Refer to the emergency flipchart in the lab room located on the main control panel for more information on specific types of emergencies ACCOMMODATIONS If you think you could benefit from classroom accommodations for a disability physical mental emotional or learning please contact our Accessibility Resources office Call 360 752 8345 email ar btc ctc edu or stop by the AR Office in the Admissions and Student Resource Center ASRC Room 106 College Services Building file 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 1 week of Fall Winter and Spring quarters The particular
52. 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 diagnostic skills Feedback questions sets of practice problems at the end of each course section challenge your knowledge and problem solving ability in current as as well as first year Electronics subjects These are optional assignments counting neither for nor against your grade Their purpose is to provide you and your instructor with direct feedback on what you have learned 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 cri
53. 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 a high temperature alarm file 102342 56 Question 34 Programming Challenge and Comparison Conveyor start stop control with safety switch Suppose we wish to control the starting and stopping of a large conveyor belt at a factory using a PLC This control system will use a Start pushbutton a Stop pushbutton and an emergency shut down pull cable allowing anyone along the conveyor s length to stop the belt simply by tugging on a steel cable this is akin to the stop cable used on public buses for passengers to signal to the driver their intent to get off at the next stop Inputs e Start pushbutton momentary NO pushing this button closes the switch to energize the PLC input e Stop pushbutton momentary NC pushing this button opens the switch to de energize the PLC input e Emergency stop cable latching NC tugging on the cable opens the switch to de energize the PLC input Outputs e Motor contactor energizing this PLC output starts the conveyor belt motor Write a PLC program performing this function and demonstrate its operation using switches connected to its inputs to simula
54. e connecting your PC to your PLC with any necessary drivers installed on your PC to allow it to communicate Like all serial based communications the PC needs to be properly configured with regard to bit rate number of data bits number of stop bits and parity in order to communicate with the PLC The software you will be using should have an auto detect feature which will sequentially try various combinations of these parameters until it finds one combination that works Note on Allen Bradley PLCs you must first install and run software called RSLinz which manages communications between your PC and PLC before you start up the programming software RSLogiz After that your next step is to use programming software installed in a personal computer to program your PLC with some simple function consisting of contact and coil instructions The purpose of a virtual contact in a PLC program is to read data bits from memory while the purpose of a virtual coil in a PLC program is to write data bits to memory Thus you will create programs for the PLC using virtual contacts to read the states of real world switches connected to inputs on the PLC and using virtual coils to control real world outputs on the PLC to energize loads such as lamps and solenoids The interconnections and arrangements of these virtual contacts and coils determine the logic implemented by the PLC specifying the conditions necessary to energize real world dev
55. e if you were tasked with solving this problem e A helpful problem solving tip is to annotate each contact in the PLC program to show what its real world function is For example contact I1 0 3 may be labeled OL because that is the real world switch status it senses Annotate all contacts in this program and explain how this annotation is helpful in analyzing the program e Describe the purpose of the contact labeled 0 0 2 in this program explaining why it is often referred to as a seal in contact 47 file i04662 48 Question 26 Two technicians Jill and Bob work on programming Siemens S7 200 PLCs to control the starting and stopping of electric motors Both PLCs are wired identically as shown 120 VAC 480 VAC 3 0 supply supply SIEMENS Q QQ Q Q Q Q 0Q0QQQQQQQQ ton SIMATIC iL 00 O 02 03 2 o4 05 06 3 07 10 14 S7 200 eormanannannnaonn CI SF DIAG eee ar aie ge RB Sa AC DC Relay C RUN E stor Og 2 3 ey Og ees NEG 2 EDID EJ El EJ ie E E EJ ED iM 00 04 02 03 04 05 06 07 2M 10 14 12 13 14 15 kapas Q Q Q Q oQ Q Q b QQbQ oQ b o0 o oe Start Stop However despite being wired identically the two technicians PLC programs are quite different Jill s program uses retentive coil instructions Set and Reset coils while Bob s uses
56. e of this PLC control is to start and stop a water pump drawing water from a well to maintain a minimum water level in a storage tank The level switch measures the water level in the storage tank to control the pump The problem is the pump will overheat if run continuously so a high temperature cutout switch is installed at the motor to sense motor temperature and shut off the pump if the motor gets too hot The PLC will immediately shut off the motor if it senses a high temperature and refuse to re start the motor for at least 5 minutes after the temperature has fallen below the temperature switch s trip point Someone else has already written the program for this PLC leaving you to figure out which contact on each switch NO or NC must be connected to which terminal on the input card Sketch wires for all connections to complete this system based on this pre written Ladder Diagram program I 1 4 TOF Timer Off Delay EN Timer T4 1 DN 1 0 300 Time Base Preset file 102253 90 Question 86 Calculate all voltages currents and total power in this balanced Y Y system Eline Liine Eyhase source Iphase source Ephase load Iphase load Protal file 102421 91 Question 87 The following circuit senses temperature using a thermistor with a positive temperature coefficient i e resistance increases as temperature increases phi 10 VDC Cable 1
57. e somehow added value Nothing in the License prohibits the application of a more restrictive license or no license at all to derivative works This means you can add your own content to that which I have made and then exercise full copyright restriction over the new derivative work choosing not to release your additions under the same free and open terms An example of where you might wish to do this is if you are a teacher who desires to add a detailed answer key for your own benefit but not to make this answer key available to anyone else e g students Note the text on this page is not a license It is simply a handy reference for understanding the Legal Code the full license it is a human readable expression of some of its key terms Think of it as the user friendly interface to the Legal Code beneath This simple explanation itself has no legal value and its contents do not appear in the actual license file license 20 Questions Question 1 Read and outline the introduction and PLC Examples sections of the Programmable Logic Controllers chapter in your Lessons In Industrial Instrumentation textbook Note the page numbers where important illustrations photographs equations tables and other relevant details are found Prepare to thoughtfully discuss with your instructor and classmates the concepts and examples explored in this reading file i00460 Question 2 Read selected portions of the Sieme
58. ens S7 200 PLC connected to a pair of momentary contact pushbutton switches and light bulbs as shown in this illustration 24 VDC a j SIEMENS o S7 200 DC CPU 224XP Q0 El El El El El EU ET PT QtET El DC DC DC L SF DIAG O A 2 8 4 5 6 7 DT CI RUN 1 stop LOW 2 3 4 5 0 7 Ana 2 3 4 5 WOOOOOOO00 nogooon000 mua ian 1M 0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 2M 1 0 A ers 1 3 1 4 is L i i Switch A Examine the following relay ladder logic RLL program for this Siemens PLC determining the statuses of the two lamps provided both switches are simultaneously pressed by a human operator 10 7 Q0 1 j IQ 7 I1 2 Q0 3 Finally draw color highlighting showing how these contact instructions will appear in an online editor program given the stated input conditions file 104664 51 Question 29 Suppose we have a Koyo CLICK PLC connected to three momentary contact pushbutton switches as shown in this illustration CLICK C0 02DD1 D Koyo PWR D RUN D ERR D RUN PORT 1 1 CO RX1 D Tx2 D RX2 D PORT 2 PORT 3 RS 485 1x3 O RX3 1 LG 24 VDC Determine the necessary switch actuation statuses i e pressed versus unpressed to turn the lamp on given the following program running in the PLC pS Suggestio
59. ermine the switch stimuli i e required pressure temperature and level given the live display of the ladder logic program shown here x1 ails Also determine the status of the lamp connected to the PLC s Y1 output Suggestions for Socratic discussion e Identify how you could override the PLC program to force the lamp to energize if your only tool at hand was a screwdriver file 104667 64 Question 43 Suppose we have an Allen Bradley SLC 500 controller connected to a pair of momentary contact pushbutton switches and contactor controlling power to an electric motor as shown in this illustration 480 VAC Overload block This motor control system has a problem though the motor refuses to start when the Start pushbutton is pressed Closely examine the pictorial diagram including the status LEDs on the PLC s I O cards then identify at least two faults that could account for the motor s refusal to start Suggestions for Socratic discussion e A helpful problem solving tip is to note the PLC s I O states by examining the LED indicators on each input and output card on the PLC rack What do the LED states tell you in this particular example file 104069 65 Question 44 A NAND logic function may be built up from a regula
60. ers or hints given Answer 86 This is a graded question no answers or hints given Answer 87 This is a graded question no answers or hints given Answer 88 This is a graded question no answers or hints given Answer 89 This is a graded question no answers or hints given Answer 90 This is a graded question no answers or hints given Answer 91 Answer 92 Your loop diagram will be validated when the instructor inspects the loop with you and the rest of your team 125
61. f these counter instructions count up to How low can it count down to Based on these values how many bits do you think are used in the register to store a counter instruction s current value Sketch a simple ladder diagram program for a Siemens 7 200 PLC whereby a switch connected to input I0 5 causes a counter to increment count up and then turn on an alarm light output Q0 3 when the count reaches a value of 5 Also provide a reset function triggered by a normally open switch contact at input 10 0 to force the count value back to zero when pressed 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 o
62. he system works without any problems whatsoever and then one day management decides to scrap a run of product mid shift and start over This is when they discover the system integrator they contracted to build and program the PLC system provided no way to reset the shift production counter except to wait until the shift is over An operations manager summons you to reset the counter for them Identify at least two different ways you could reset the counter to meet their needs as quickly as possible file 100182 80 Question 66 An important pump in a chemical process is turned by an electric motor and operators want to have visual indication in the control room that the pump is indeed turning There is no way to attach a speed switch to the pump shaft that would be too easy Instead someone has installed a proximity switch near the pump shaft situated to pick up the passing of a keyway in the shaft with each rotation Thus the proximity switch will output a pulse signal when the pump shaft is spinning Pump A Proximity switch Signal cable to PLC input LLLLULI 3 2 Pulse signal when pump is running Operators wanted the indicator light in the control room to blink when the pump is running for an indication of shaft motion The problem is the shaft turns much too fast approximately 1750 RPM to directly drive the indicator with the proximity switch signal and so an Allen Bradley PLC was programmed to
63. his course you must have your own PLC trainer consisting of a working PLC and input switches all wired and ready to use Input switches i les es E peels 2 2 Indicator lamps All components should be securely mounted to a wood board or some other structure making it easy to transport and use You must have a terminal block in between the switches indicators and PLC I O terminals to allow for easy connection and disconnection of external devices to your PLC without wearing out the screws on the PLC s terminal block prematurely Separate terminal blocks are easily replaced whereas the terminal block on your PLC is likely much more expensive and inconvenient to replace Consult the user s manual for your PLC in order to determine how all devices should be wired to the input and output I O terminals Note that often there are different types of I O AC DC sourcing sinking available for the same or similar model of PLC Most PLC user s manuals give detailed diagrams showing how to connect devices to discrete I O points so be sure to follow the proper diagram for your specific PLC model Once you have your PLC wired the next step is to install and run the software used to program your programmable logic controller PLC and try to get the two devices communicating with each other This of course requires you have a special cabl
64. ic syntax of the instruction which you may copy verbatim as an example Once this simple program is loaded into your PLC s memory you can play with it to see its live behavior while viewing the program online Once you have directly observed how the instruction works your next step is to add comments to the program describing how that instruction works in your own words Be as detailed as possible here treating this activity as though you were asked to explain everything to someone who knew absolutely nothing about the instruction These comments will serve as notes to yourself later when you need to refresh your memory on how a particular instruction functions or what it is used for Do not be surprised if your instructor asks you to show your demonstration program s for particular instructions in the future If you experience difficulty using a particular instruction in a programming assignment your instructor may check to see if you have created and run a demonstration program to learn how that instruction is supposed to function Refer to the Answer section of this question to see some examples of what such a demonstration program might look like Suggestions for Socratic discussion e A helpful tip when writing your own demonstration programs is to save each one with a filename that makes it easy to locate on your personal computer For example you might wish to name each of your demonstration programs beginning
65. ices based on input conditions You will find step by step instructional tutorials for both Allen Bradley MicroLogix and Koyo CLICK PLCs in your Instrumentation Reference provided by the instructor Follow these tutorials to establish communication between your PC and your PLC and to write a simple contact and coil ladder diagram program before attempting the exercises that follow You will also find much pertinent information for programming Allen Bradley MicroLogix PLCs in the RSLogiz 500 Getting Results Guide since the SLC 500 23 line of Allen Bradley PLCs program so similarly to the MicroLogix line This example shows an Allen Bradley MicroLogix 1000 series PLC model 1761 L10BWA wired to two toggle switches and one LED indicator lamp complete with a demonstration program Note that line power 120 VAC wire connections to power the PLC have been omitted so the focus is solely on the I O wiring 1 0 1 1 1 2 3 DC 1 4 1 5 COM L CHONG Oa 1 Power Allen Bradley Ct Run c Fault MicroLogix C Force 1009 r r r VAC VAC VAC voc O1 vpc 22 vpo Of Q LED with dropping resistor Ladder Diagram program written to PLC T T0 Note how Allen Bradley I O is labeled in the program input bits designated by the letter I and output bits designated by the letter 0 Based on the wiring and program you see for this PLC identify the switch state combinations resul
66. ifferent contact instruction types offered on your PLC Describe how each of them functions e Identify the different coil instruction types offered on your PLC Describe how each of them functions e What happens when two contact instructions are linked to the same bit address in the PLC s memory Do these contact instructions operated differently or identically e What happens when two coil instructions are linked to the same bit address in the PLC s memory but driven to different states e g one energized and the other de energized e Does your PLC offer a special type of contact or other bit level instruction to detect the transistion of a bit from one state to another If so how is this instruction used e Where in the PLC s memory are the single bit registers e g input registers output registers and internal bit registers located What symbol s are used to address each one e Where in the PLC programming editor can you view the live status of contact and coil bits e Experiment with using the force utility in your PLC to force certain bits to fixed values regardless of program operation How will the operation of your program be affected if a particular input bit is forced How will the operation of your program be affected if a particular output bit is forced How can you tell from the live program display that bits have been forced to fixed values file 103354 50 Question 28 Suppose we have a Siem
67. ify the counter instruction in the program shown its input connections and also how the result of the counter reaching its pre set limit forces the motor to stop Also determine the maximum number of times the motor may be started up assuming the counter s current value goes to zero when the Reset button is pressed Finally determine how to modify this PLC program so that the counter may be manually reset by the operator without requiring a separate pushbutton labeled Reset Suggestions for Socratic discussion e If an operator presses the Start button multiple times while the motor is already running do these button presses get counted by the counter instruction or do only the real motor start up events get counted e What do you suppose the label CTD1 represents inside the counter instruction e Note the number of times the bit Y1 is referenced inside this PLC program once in a coil instruction and twice in contact instructions Is there any limit to how many times a bit address may be used in a PLC program e Describe the purpose of the first contact instruction labeled Y1 in this program explaining why it is often referred to as a seal in contact file 103589 72 Question 51 Programming Challenge Parking garage counter Suppose we wish to count the number of cars inside a parking garage at any given time by incrementing a counter each time a car enters the garage through the entry
68. ile instructional 14 Distance delivery methods Sometimes the demands of life prevent students from attending college 6 hours per day In such cases there exist alternatives to the normal 8 00 AM to 3 00 PM class lab schedule allowing students to complete coursework in non traditional ways at a distance from the college campus proper For such distance students the same worksheets lab activities exams and academic standards still apply Instead of working in small groups and in teams to complete theory and lab sections though students participating in an alternative fashion must do all the work themselves Participation via teleconferencing video or audio recorded small group sessions and such is encouraged and supported There is no recording of hours attended or tardiness for students participating in this manner The pace of the course is likewise determined by the distance student Experience has shown that it is a benefit for distance students to maintain the same pace as their on campus classmates whenever possible In lieu of small group activities and class discussions comprehension of the theory portion of each course will be ensured by completing and submitting detailed 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 question
69. ing 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 contact and coil instructions where discrete inputs on your PLC control discrete outputs on your PLC An acceptable demonstration program must meet these three criteria e Simple nothing extra included in the program to detract from the fundamental behavior of the instruction s being explored e Complete nothing missing from the program relevant to the fundamental behavior of the instruction s being explored For a contact and coil demonstration program this includes normally open and normally closed contact instructions as well as regular and retentive coil instructions e 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 e Identify the d
70. ions where they are required to research and think independently In all portions of the curriculum the goal is to avoid a passive learning environment favoring instead active engagement of the learner through reading reflection problem solving and experimental activities The curriculum may be roughly divided into two portions theory and practical Theory In the theory portion of each course students independently research subjects prior to entering the classroom for discussion This means working through all the day s assigned questions as completely as possible This usually requires a fair amount of technical reading and may also require setting up and running simple experiments At the start of the classroom session the instructor will check each student s preparation with a quiz Students then spend the rest of the classroom time working in groups and directly with the instructor to thoroughly answer all questions assigned for that day articulate problem solving strategies and to approach the questions from multiple perspectives To put it simply fact gathering happens outside of class and is the individual responsibility of each student so that class time may be devoted to the more complex tasks of 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
71. is 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 counter instructions where discrete inputs on your PLC control discrete 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 counter demonstration program this includes up counters down counters and up down counters all with provision for re setting 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 counter instruction types offered on your PLC What does each one of them do How can you make a single counter both increment count up and decrement count down Where in the PLC programming editor can you view the live status of a counter instruction Where in the PLC s memory are the counter variables e g accumulated value set
72. ith switch 1 and switch 2 The lamp energizes when switch 1 is on and switch 2 is off or when switch 1 is off and switch 2 is on Answer 5 Answer 6 Answer 7 Answer 8 A good problem solving technique to apply in both diagrams is annotation where you indicate the presence of continuity and power versus non continuity unpowered In PLC programs this usually appears in the form of color highlighting surrounding each instruction symbol virtual contact or virtual coil Answer 9 107 Answer 10 Demonstration program showing some basic bit instructions in an Allen Bradley MicroLogix PLC When the switch connected to input 0 is turned on the input bit l 0 0 goes from 0 to 1 and this contact becomes colored on my laptop PC s screen That color is sent to the coil instruction where it turns on output bit O 0 1 This makes output channel 1 turn on energizing the light bulb wired to that output When I turn off input switch 0 the contact un colors and so does the output coil O 0 1 This program rung makes output O 0 1 be the same state as input 0 0 T4070 O 0 1 S When the same switch on input 0 is turned on the input bit l 0 0 goes from 0 to 1 and this contact becomes un colored This makes the output bit O 0 2 turn off so that O 0 2 is always the opposite state of 1 0 0 I 0 0 O 0 2 Placing these two contact instruction in series with each other makes it so the coil o
73. k pliers e Diagonal wire cutters sometimes called dikes Screwdrivers e Slotted 1 8 and 1 4 shaft e Phillips 1 and 2 e Jeweler s screwdriver set e Optional Magnetic multi bit screwdriver e g Klein Tools model 70035 Electrical e Multimeter Fluke model 87 IV or better e Alligator clip jumper wires e Soldering iron 10 to 40 watt and rosin core solder e Resistor potentiometer diode assortments from first year lab kits e Package of insulated compression style fork terminals 14 to 18 AWG wire size 10 stud size e Wire strippers terminal crimpers for 10 AWG to 18 AWG wire and insulated terminals e Optional ratcheting terminal crimp tool e g Paladin 1305 Ferrules Direct FDT10011 or equivalent Safety e Safety glasses or goggles available at BTC bookstore e Earplugs available at BTC bookstore Miscellaneous e Simple scientific calculator non programmable non graphing no conversions TI 30Xa or TI 30XIIS recommended Required for some exams Masking tape for making temporary labels Permanent marker pen Teflon pipe tape Utility knife Tape measure 12 feet minimum Flashlight An inexpensive source of tools is your local pawn shop Look for tools with unlimited 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 situat
74. l 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 7 104 iagram D iring Sample Input W A dd Ova 02 S oane Y 01S Buus OGArZ 1 ndul 8 319S1q Sdl 97Z1 yauiqed O1d p nett uoe dwe yoojg snd 8z gr xoq uonounf p 9 4 Bulsu ISd S sdup Ol HSd Pie 105 Sample Output Wiring Diagram L g OWA Oct yoes dwe 1 yoo q snd 0Z HYd 81929 due uup v Oz HYd L 01S OVIHL OVA Or2 001 indino 9jaJ9SIq 8VO 9PZ1 7 Ad Ad 21029 veal plougjos du JaUIged O1d 8z ar xoq uonoun pals pial file 101880 106 Answers Answer 1 Answer 2 Input register byte 1 bit 4 11 4 Output register byte 0 bit 2 QO 2 Variable memory double word starting at byte 105 VD105 a double word consisting of 4 bytes or 32 bits Answer 3 Input file element 1 bit 4 1 1 4 Output file element 0 bit 2 0 0 2 Timer 6 accumulator word T4 6 ACC Answer 4 For the Allen Bradley MicroLogix example the lamp will energize only when switch 0 is turned off and switch 1 is turned on For the Siemens 7 200 example the lamp will energize when switch 0 is turned on or if switch 1 is turned off or both conditions occur simultaneously For the Koyo example the lamp will energize according to the Exclusive OR function w
75. lane and decrementing the same counter each time a car leaves the garage through the exit lane One discrete input of the PLC will connect to a switch detecting the passing of each car through the garage entry and another discrete input of the PLC will connect to a switch detecting cars passing out the garage exit The PLC must be equipped with a way to for the garage attendant to manually reset the counter to zero Write a PLC program to perform this function and demonstrate its operation using switches connected to its inputs to simulate the discrete inputs in a real application Suggestions for Socratic discussion e What type of switches would you recommend to detect cars driving into the parking garage e How are you able to view the counter instruction s current count value as the program runs e s there any way to fool this system so that it does not hold an accurate count of cars inside the garage PLC comparison e Allen Bradley Logix 5000 CTUD count up down instruction e Allen Bradley SLC 500 CTU and CTD instructions e Siemens S7 200 CTUD count up down instruction e Koyo Automation Direct DirectLogic UDC counter instruction file 103684 73 Question 52 Question 53 Question 54 Question 55 Question 56 Question 57 Question 58 Question 59 Question 60 74 Question 61 A PLC is being used to monitor the oil pressure for a steam turbine drivi
76. les 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 92 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 system 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 termina
77. ley MicroLogix 1000 Programmable Controllers Bulletin 1761 Controllers user manual document 1761 6 3 July 1998 and answer the following questions Locate the section discussing the PLC s operating cycle otherwise known as a scan cycle and describe the sequence of operations conducted by the PLC on an ongoing basis Locate the section discussing the PLC s memory types EEPROM and RAM and describe the functions of each A very important aspect to learn about any PLC is how to specify various locations within its memory Each manufacturer and model of PLC has its own way of addressing memory locations analogous to the different ways each postal system within each country of the world specifies its mailing addresses Locate the section of the manual discussing addressing conventions Addressing Data Files and then answer these questions Identify the proper address notation for a particular bit in the Allen Bradley PLC s memory bit number 4 of element 1 within the input file Identify the proper address notation for a particular bit in the Allen Bradley PLC s memory bit number 2 of element 0 within the output file Identify the proper address notation for a word of data in the Allen Bradley PLC s memory the accumulator word ACC of timer number 6 within data file T4 file 103604 22 Question 4 In order to learn PLC programming and perform the exercises necessary for exams in t
78. ment in the lab label that equipment with a detailed description of its symptoms Teamwork You will work in instructor assigned teams to complete lab assignments just as you will work in teams to complete complex assignments on the job As part of a team you must keep your teammates informed of your whereabouts in the 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 f
79. mentation courses follow an inverted model where lecture is replaced by independent study and class time is devoted to addressing your questions and demonstrating your learning Most students require a minimum of 3 hours daily study time outside of school Arriving unprepared e g homework incomplete is 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 initi
80. 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 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 100 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
81. n 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 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
82. nction 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 responsibilities 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
83. ng an electrical generator shutting steam off to the turbine if ever the oil pressure drops below a 10 PSI limit The turbine s lubrication oil pump is driven by the turbine shaft itself supplying itself with pressurized lubricating oil to keep all the turbine bearings properly lubricated and cooled Start O t Stop O s Oil pump Generator 20 PSI 2 H air supply vent Steam supply Another technician programmed the PLC for the start stop function but this program has a problem Real world I O wiring Discrete input Discrete output Start pushbutton card card SR IN_switch_Start Solenoid coil Stop pushbutton OUT_valve IN_switch_Stop Low oil pressure AS IN_oil_press PLC program IN_switch_Start IN_switch_Stop IN_oil_press OUT_valve OUT_valve Identify what this problem is and fix it Hint the oil pump is driven by the turbine and as such cannot generate any oil pressure until the turbine begins to spin file 100189 75 Question 62 This Siemens S7 200 PLC is supposed to count the number of cars entering a parking garage using a pressure sensitive switch that the cars drive over when entering the garage The car count value is sent to a computer in the main office via a network cable plugged into the PLC The parking attendant is able to reset the count to 0 at the end of his shift using a key switch Network ca
84. nly gets colored if both of the contacts become colored O 0 3 turns on only if switch 4 is on and switch 5 is off 1 0 4 T2075 04073 oar e 108 Demonstration program showing up and down counter instructions in an Allen Bradley MicroLogix PLC The CTU instruction is a counter that counts in the up direction when its input is toggled When the Preset count value reached the Done bit DN activates 1 0 0 CTU Count Up CU Counter C5 0 Preset 12 Accum 5 DN The CTD instruction is a counter that counts in the down direction when its input is toggled When the Preset count value reached the Done bit DN activates Note how both the CTU and CTD counter instructions reference the exact same counter structure in memory C5 0 Thus the two instructions both act on the same accumulated value I 0 1 CTD Count Down CD Counter C5 0 Preset 12 Accum 5 DN When the counter C5 0 accumulator value equals or exceeds the Preset value contact C5 0 DN becomes colored passing color to the coil O 0 0 to turn on a light bulb connected to output channel 0 C5 0 DN O 0 0 C a x l Allen Bradley counter instructions can only be reset by external commands in this case a special coil instruction sharing the same address as the counter instruction C5 0 Activating the I 0 1 input causes the RES coil to become colored which then resets the CTU instruction s Ac
85. ns SIMATIC S7 200 Programmable Controller System Manual document A5E00307987 04 August 2008 and answer the following questions Locate the section discussing the PLC s scan cycle and describe the sequence of operations conducted by the PLC on an ongoing basis Locate the section discussing the PLC s memory types Permanent Memory versus Retentive Data Memory and such and describe the functions of each A very important aspect to learn about any PLC is how to specify various locations within its memory Each manufacturer and model of PLC has its own way of addressing memory locations analogous to the different ways each postal system within each country of the world specifies its mailing addresses Locate the section of the manual discussing addressing conventions Accessing the Data of the 7 200 and then answer these questions Identify the proper address notation for a particular bit in the Siemens PLC s memory bit number 4 of byte 1 within the process image input register Identify the proper address notation for a particular bit in the Siemens PLC s memory bit number 2 of byte 0 within the process image output register Identify the proper address notation for a double word of data in the Siemens PLC s memory beginning at byte 105 within the variable memory area How many bits are contained in a double word file 103605 21 Question 3 Read selected portions of the Allen Brad
86. ns for Socratic discussion e Identify the significance of the labels X and Y for this PLC s bits What do you suppose X signifies What do you suppose Y signifies file 104638 52 Question 30 Suppose we have an Allen Bradley MicroLogix 1000 PLC connected to three momentary contact pushbutton switches as shown in this illustration ENT 1 0 Val 1 2 1 3 DC 1 4 1 5 L J COM con L 000g00g C Power C Run 1 Fault C Force 000g p gt Lo 85 264 VAC r 1 vac vc l vc ve mi aN E LOOM ypo Ol ype OA ige O8 Determine the bit statuses of I 0 0 I 0 1 and I 0 3 when switch A is pressed switch B is unpressed released and switch C is pressed file i04685 53 Question 31 Suppose we have a Siemens S7 200 PLC connected to two process switches as shown in this illustration 24 VDC SIEMENS Q Q Q Q Q SIMATIC AM 1L 00 01 02 03 04 2M 2 05 06 07 10 i1 e m L pc 57 200 CPU 224XP aonmnmm000004 00 C SFIDIAG ON ee sey DA PEPE C RUN C STOP _ I Q 4 2 9 4 5 7 J 2 8 5 W OOOOOO000 1000000 Port 1 Port 0 Determine the bit statuses of 10 2 and 11 1 when the temperature switch senses 122 F and the flow switches senses 15 GPM file 104686 54 Question 32 Suppose we have an Allen Bradley SLC 500 PLC connected to
87. of gravity free fall Earth standard 9 806650 meters per second per second m s 32 1740 feet per second per second ft s 17 Physical constants Speed of light in a vacuum c 2 9979 x 10 meters per second m s 186 281 miles per second mi s Avogadro s number Na 6 022 x 1023 per mole mol 1 Electronic charge e 1 602 x 10 19 Coulomb C Boltzmann s constant k 1 38 x 1023 Joules per Kelvin J K Stefan Boltzmann constant o 5 67 x 1078 Watts per square meter Kelvin W m K Molar gas constant R 8 314 Joules per mole Kelvin J mol K Properties of Water Freezing point at sea level 32 F 0 C Boiling point at sea level 212 F 100 C Density of water at 4 C 1000 kg m 1 g cm 1 kg liter 62 428 lb ft 1 94 slugs ft Specific heat of water at 14 C 1 00002 calories g C 1 BTU Ib F 4 1869 Joules g C Specific heat of ice 0 5 calories g C Specific heat of steam 0 48 calories g C Absolute viscosity of water at 20 C 1 0019 centipoise cp 0 0010019 Pascal seconds Pa s Surface tension of water in contact with air at 18 C 73 05 dynes cm pH of pure water at 25 C 7 0 pH scale 0 to 14 Properties of Dry Air at sea 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 1075 Pascal seconds Pa s file c
88. of the light bulb given all possible switch status combinations Switch A Switch B Light Bulb Unpressed Unpressed Unpressed Pressed Pressed Unpressed Pressed Pressed 62 file i03360 Question 41 Suppose we have a Siemens S7 200 PLC connected to a pair of momentary contact pushbutton switches and light bulbs as shown in this illustration 24 VDC SIEMENS Q Q Q Q Q tm L SIMATIC 1M 1L 0 0 0 1 0 2 0 3 0 4 2M 2L 05 0 6 07 10 14 S7 200 oc CPU 224XP oq DC DC DC CI SF DIAG O 4 2 39 4 5 amp 7 O LJ RUN 4 STOP Port 1 Port 0 OA ARBAB 2 0 q 252 s W QOOOOO0OO000 1 oo0000 Switch B ale Examine the following relay ladder logic RLL program for this Siemens PLC determining the statuses of the two lamps provided switch A is pressed by a human operator and switch B is unpressed 10 7 Q0 1 yH H IO 7 Ilaz Q0 3 Furthermore determine whether the inputs and outputs of this particular PLC as shown are sourcing or sinking file 104170 63 Question 42 Suppose we have a Koyo CLICK PLC connected to three process switches as shown in this illustration CLICK C0 02DD1 D Koyo PWR D RUN 7 ERR CJ RUN STOP PORT 1 CO RX1 D Tx2 D Rx2 CI PORT 2 PORT 3 RS 485 x O RX3 d Le 24 VDC Det
89. oint the location of the problem file 103683 76 Question 63 This Siemens S7 200 PLC has been programmed to count the number of people in a room by incrementing a counter every time a person enters through the doorway and decrementing that same counter whenever someone exits through the same doorway The two optical switches activate whenever their respective light beams are broken by someone passing through Their horizontal separation is just a couple of inches much less than the girth of a person s torso The operating status of each switch is that it energizes the PLC input when the light beam is broken Light sources Entering AW Photo switche PLC SIEMENS AAAI ee Examine the program in this PLC for counting people and determine how it is able to differentiate between a person entering the room and a person leaving the room 11 0 11 3 P J CU CTUD 11 3 I1 0 P J CD QU R qQp LD Pv cvH Suggestions for Socratic discussion e Explain how a timing diagram of the switch states would be helpful in analyzing the operation of this PLC program e Transition edge detecting functions are implemented in Allen Bradley PLCs using the one shot rising OSR instruction Research how the OSR instruction is used and how it differs from the P and N contacts shown in this
90. onversion_constants 18 Question 0 How to get the most out of academic reading Articulate your thoughts as you read i e have a conversation with the author This will develop metacognition active supervision of your own thoughts Write your thoughts as you read noting points of agreement disagreement confusion epiphanies and connections between different concepts or applications These notes should also document important math formulae explaining in your own words what each formula means and the proper units of measurement used Outline don t highlight Writing your own summary or outline is a far more effective way to comprehend a text than simply underlining and highlighting key words A suggested ratio is one sentence of your own thoughts per paragraph of text read Note points of disagreement or confusion to explore later Work through all mathematical exercises shown within the text to ensure you understand all the steps Imagine explaining concepts you ve just learned to someone else Teaching forces you to distill concepts to their essence thereby clarifying those concepts revealing assumptions and exposing misconceptions Your goal is to create the simplest 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 trou
91. or them Grades Employers prize trustworthy hard working knowledgeable resourceful problem solvers The grade you receive in any course is but a partial measure of these traits What matters most are the traits themselves which is why your instructor maintains detailed student records including individual exam scores 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 i
92. point value located What symbol s are used to address each one How far up can a counter count How far down Note that this will be related to the number of bits the counter instruction uses to track its current accumulated value What happens when a counter reaches its preset value How do you use this event to trigger something else to happen in the program What happens to the counter s current value when it reaches its preset value Does the counter stop counting or does it continue counting past this threshold e When a counter is reset does its current value begin at zero or one e Is it possible to preload a counter instruction so that it doesn t have to begin at the starting value when the PLC program runs anew What happens to the counter s current value when it reaches its maximum value Does the counter instruction stop counting or does it do something else file 103353 69 Question 48 Suppose we have a Koyo CLICK PLC connected to three process switches as shown in this illustration CLICK C0 02DD1 D Koyo Trip 135 F PWR D RUN D ERR D RUN Trip 23 inches STOP PORT 1 Trip 17 PSI O Rx1 D Tx2 D Rx2 J PORT 2 PORT 3 RS 485 xXx O RX3 L LG Determine the process conditions i e temperature level and pressure values given the live display of the ladder logic program shown here X1 X2 X3 Y1
93. put_4 Input_switch_2 Turn on status highlighting within the programming software environment so that you may see the virtual power flow through the conductive contacts as you test the program Suggestions for Socratic discussion How are discrete input and output points associated with contacts and coils in the ladder logic program e How do you draw vertical connecting lines in the ladder logic program e How do you assign alias names to inputs and outputs for easier program readability For example how do you assign an English name to the input I 2 4 Input channel 4 on card 2 on an Allen Bradley SLC 500 PLC so that it reads as Input_switch_4 in the program instead of I 2 4 in the programming software s display e Where is the software function pull down menu option button hot key etc located that allows you to turn on contact status highlighting in the PLC programming software file 103667 34 Question 13 Suppose we have an Allen Bradley MicroLogix 1000 PLC connected to three momentary contact pushbutton switches as shown in this illustration Q O O OGDOOOOOS 24y 1 0 1 1 1 2 la DC 1 4 1 5 COM L J CC DCOUT COM L UOUUO00 C Power C Run 1 Fault C Force 000g P gt Lo 85 264 VAC r 1 vac vc l vac ve mi wns OO va io ivu OA wna OF Determine the bit statuses of I 0 0 I 0 1 and
94. r AND function plus an inverter function a NOT gate on the output AND NOT NAND H gt s equivalent to gt The same strategy of building a NAND gate may be done in PLC ladder diagram programming by combining a normally closed contact instruction with two contacts in series Examine these two Allen Bradley PLC programs and explain why the left hand program is wasteful while the right hand program makes more efficient use of available bits Allen Bradley MicroLogix SLC Wasteful Efficient I 0 7 O 2 0 I 0 7 B3 0 0 x O 52 71 O 2 1 Examine these two Siemens S7 PLC programs and explain why the left hand program is wasteful while the right hand program makes more efficient use of available bits in the same ways the Allen Bradley example programs were wasteful efficient Siemens Step 7 S7 Wasteful Efficient 10 4 10 7 Q2 0 10 4 10 7 M0 0 Q2 0 Q2 1 MO 0 Q2 1 x x Note many novice PLC programmers commit this error of wasting valuable I O as they write their programs file 104092 66 Question 45 Read selected portions of the Siemens SIMATIC S7 200 Programmable Controller System Manual document A5E00307987 04 August 2008 and answer the following questions Identify the different types of SIMATIC counter instructions Identify a practical application for a counter instruction programmed into a PLC How high can one o
95. r 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 99 Lab Exercise wiring the system The Instrumentation lab is set up to facilitate the construction of working systems with over a dozen junction 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
96. s bad Circuit 4 This circuit is bad 112 Answer 20 Circuit 1 This circuit is bad Circuit 2 This will work O PP rE Circuit3 This circuit is bad Circuit 4 This will work 113 Answer 21 Demonstration program showing some basic bit instructions in an Allen Bradley MicroLogix PLC When the switch connected to input 0 is turned on the input bit l 0 0 goes from 0 to 1 and this contact becomes colored on my laptop PC s screen That color is sent to the coil instruction where it turns on output bit O 0 1 This makes output channel 1 turn on energizing the light bulb wired to that output When I turn off input switch 0 the contact un colors and so does the output coil O 0 1 This program rung makes output O 0 1 be the same state as input 0 0 T4070 O 0 1 S When the same switch on input 0 is turned on the input bit l 0 0 goes from 0 to 1 and this contact becomes un colored This makes the output bit O 0 2 turn off so that O 0 2 is always the opposite state of 1 0 0 I 0 0 O 0 2 Placing these two contact instruction in series with each other makes it so the coil only gets colored if both of the contacts become colored O 0 3 turns on only if switch 4 is on and switch 5 is off I 0 4 I 0 5 0 0 3 H m Note your own demonstration program should contain some retentive coil instruction as well in order for you to be able to observe what these instructions do
97. s be re answered by the student to correct any misunderstandings before moving on Labwork is perhaps the most difficult portion of the curriculum for a distance student to complete since the equipment used in Instrumentation is typically too large and expensive to leave the school lab facility Distance students must find a way to complete the required lab activities either by arranging time in the school lab facility and or completing activities on equivalent equipment outside of school e g at their place of employment if applicable Labwork completed outside of school must be validated by a supervisor and or documented via photograph or videorecording Conventional students may opt to switch to distance mode at any time This has proven to be a benefit to students whose lives are disrupted by catastrophic events Likewise distance students may switch back to conventional mode if and when their schedules permit Although the existence of alternative modes of student participation is a great benefit for students with challenging schedules it requires a greater investment of time and a greater level of self discipline than the traditional mode where the student attends school for 6 hours every 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 exi
98. 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 102 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 Correctly 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 a 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
99. sor Tony Kuphaldt permits others to copy distribute display and otherwise use this work In return licensees must give the original author s credit For the full license text please visit http creativecommons org licenses by 1 0 on the internet More detailed explanation of Attribution License Under the terms and conditions of the Creative Commons Attribution License you may make freely use make copies and even modify these worksheets and the individual source files comprising them without having to ask me the author and licensor for permission The one thing you must do is properly credit my original authorship Basically this protects my efforts against plagiarism without hindering the end user as would normally be the case under full copyright protection This gives educators a great deal of freedom in how they might adapt my learning materials to their unique needs removing all financial and legal barriers which would normally hinder if not prevent creative use Nothing in the License prohibits the sale of original or adapted materials by others You are free to copy what I have created modify them if you please or not and then sell them at any price Once again the only catch is that you 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 hav
100. stion 70 Question 71 Question 72 Question 73 Question 74 Question 75 Question 76 Question 77 Question 78 Question 79 Question 80 85 Question 81 Suppose we have an Allen Bradley MicroLogix 1000 PLC connected to a temperature switch and a flow switch A Trip 15 GPM E D s 5 G 1 BEN 1 0 1 1 1 2 1 3 DC 1 4 V5 L J COM DC OUT L 00000 Co Power o Trip 200 F lun Fault Force i VAC VAC VAC OO ypg O1 vpe O 2 ypc 3 Q Q We wish for the lamp to come on when the temperature is below 200 degrees F and when the flow rate is below 15 GPM Write a RLL program for the PLC complete with correct address labels for each of the virtual contacts to fulfill this function 0 0 file 102375 86 Question 82 Analyze this Allen Bradley PLC program and explain what it is supposed to do Motor ae CTU Count Up Counter C5e2 Preset 17 0 CU DN Accum Start Stop Motor Jes I 0 C542 O 1 0 1 DN 0 Motor O 1 0 Reset I 0 C5 2 c o 2 file 102377 87 Question 83 In relay ladder logic RLL programming it is considered bad practice to have multiple instances of an identical standard relay coil in a program Timer_01 Level_low Pump_run Switch_hand Identical coils OL_contact Sump_wet Pump_run A A Explain why this is considered
101. stor switch circuits are properly configured and some are not Identify which of these circuits will function properly i e turn on the load when the switch closes and which of these circuits are mis wired Circuit 1 Circuit 2 Circuit 3 Circuit 4 Circuit 5 Circuit 6 file 101004 58 Question 36 In each of the following circuits the light bulb will energize when the pushbutton switch is actuated Assume that the supply voltage in each case is somewhere between 5 and 30 volts DC with lamps and resistors appropriately sized Circuit 1 Circuit 2 Circuit 3 _ HI Circuit 4 Circuit 5 Circuit 6 However not all of these circuits are properly designed Some of them will function perfectly but others will function only once or twice before their transistors fail Identify the faulty circuits and explain why they are flawed file i01005 59 Question 37 Draw the necessary wire connections so that bridging the two contact points with your finger creating a high resistance connection between those points will turn the light bulb on Contact points _ T file i01006 Question 38 Choose the right type of bipolar junction transistor for each of these switching applications drawing the correct transistor symbol inside each circle V V V Transistor sinking L from load Switch sinking current Tr
102. sts 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 1021 Symbol Y Zeta 1021 Symbol Z Exa 10 8 Symbol E Peta 1015 Symbol P Tera 1012 Symbol T Giga 10 Symbol G Mega 10 Symbol M Kilo 10 Symbol k Hecto 102 Symbol h Deca 10 Symbol da Deci 107 Symbol d Centi 107 Symbol c Milli 107 Symbol m Micro 106 Symbol p Nano 107 Symbol n Pico 10 12 Symbol p Femto 1071 Symbol f Atto 107 8 Symbol a Zepto 107 Symbol z Yocto 10 24 Symbol y METRIC PREFIX SCALE T G M k m u n p tera giga mega kilo none milli micro nano pico POE 102 OP Ao TOP MO OTe TOT 0S 0 27 IOIO 302 hecto deca deci centi h da d c Conversion formulae for temperature F C 9 5 32 C F 32 5 9 R F 459 67 K C 273 15 Conversion equivalencies for distance 1 inch in 2 540000 centimeter cm 1 foot ft 12 inches in 1 yard yd 3 feet ft 1 mile mi 5280 feet ft 16 Conversion equivalencies for volume 1 gallon gal 231 0 cubic inches in3 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
103. t you fix it Non negotiable terms disciplinary action up to and including immediate failure of a course will result from academic dishonesty e g cheating plagiarism willful safety violations theft harassment intoxication destruction of property or willful disruption of the learning work environment Such 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 loc
104. te comments for each rung of your program explaining in your own words what each instruction does file 104517 43 Question 22 Suppose a Siemens 545 PLC has the following input bit states e X1 0 e X2 1 e X3 0 Sketch color highlighting for the contacts and coils in the PLC s program given these bit statuses also determining the status of output bit Y1 Suggestions for Socratic discussion e PLC training expert Ron Beaufort teaches students to think of a normally open PLC program contact instruction as a command to the PLC s processor to Go look for a 1 Conversely he teaches students to think of a normally closed instruction as a command to Go look for a 0 Explain what Mr Beaufort means by these phrases and how this wisdom relates to this particular problem Incidentally Mr Beaufort s excellent instructional videos available freely on YouTube are quite valuable to watch e Identify the significance of the labels X and Y for this PLC s bits What do you suppose X signifies What do you suppose Y signifies e Sketch a logic gate diagram implementing the same function as this PLC program file 104688 44 Question 23 Examine this live display of a Siemens S7 300 PLC s program and from this determine all bit statuses represented by the color highlighting in this ladder logic program TO 17 Q0 1 m e I0 7
105. te the discrete inputs in a real application 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 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 Suggestions for Socratic discussion e How do you keep the motor latched on when the momentary Start switch is released e Which is simpler implementing this function using normal program coils or implementing this function using retentive coils set and reset or latch and unlatch file 102340 57 Question 35 Some of the following transi
106. ted input conditions Suggestions for Socratic discussion e Identify the significance of the labels I and O for this PLC s bits e Identify the significance of the first and second numbers in each bit label e g the numbers 1 and 2 in the bit address I 1 2 for example What pattern do you see as you compare the I O connections with the respective contact instructions in the PLC program file 104628 46 Question 25 Suppose we have an Allen Bradley MicroLogix 1000 controller connected to a pair of momentary contact pushbutton switches and contactor controlling power to an electric motor as shown in this illustration Start switch Il 2 8 DC M4 I5 L OOOUUU0 Ca Power Stop switch Ct Run C Fault C Force 000g r 85 264 VAC VAG VAG VAG VAG i an E e 90 yoo oi liee O2 yoo 08 Contactor coil This motor control system has a problem though the motor refuses to start when the Start pushbutton is pressed Examine the live display of the ladder logic program inside this Allen Bradley PLC to determine what the problem is assuming an operator is continuously pressing the Start pushbutton as you examine the program I 0 3 I 0 2 T 00 0 0 2 0 0 2 Identify at least two causes that could account for all you see here Suggestions for Socratic discussion e Identify what your next troubleshooting step would b
107. terion referenced i e no grading on a curve 100 gt A gt 95 95 gt A gt 90 90 gt B gt 86 86 gt B gt 83 83 gt B gt 80 80 gt C gt 76 76 gt C gt 73 73 gt C gt 70 minimum passing course grade 70 gt D gt 66 66 gt D gt 63 63 gt D gt 60 60 gt F A graded preparatory quiz at the start of each classroom session gauges your independent learning prior to the session A graded summary quiz at the conclusion of each classroom session gauges your comprehension of important concepts covered during that session If absent during part or all of a classroom session you may receive credit by passing comparable quizzes afterward or by having your preparatory work reading outlines work done answering questions thoroughly reviewed prior to the absence Absence on a scheduled exam day will result in a 0 score for the proportional exam unless you provide documented evidence of an unavoidable emergency If you fail a mastery exam you must re take a different version of that mastery exam on a different day Multiple re tries are allowed on a different version of the exam each re try There is no penalty levied on your course grade for re taking mastery exams but failure to successfully pass a mastery exam by the due date i e by the date of the nezt exam in the course sequence will result in a failing grade F for the course If any other mastery objectives are
108. the MSB has a negative place weight value of 32768 Answer 46 Answer 47 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 122 Answer 48 Temperature below 135 F Leve above 23 inches Pressure below 17 PSI Answer 49 If the lamp is energized we know that the top two virtual contacts X1 and X2 are colored and or the bottom two virtual contacts X3 and X2 are colored For the top two virtual contacts to be colored X1 must be 0 and X2 must be 1 This equates to a pressure less than 32 PSI and a level less than 10 inches For the bottom two virtual contacts to be colored X3 must be 1 and X2 must be 0 This equates to a temperature greater than 99 F and a level greater than 10 inches Answer 50 This PLC program allows the motor to start up 7times If you thought the correct number of start ups was eight consider the fact that the counter s output bit CT1 gets set when the counter s current value equals the SetPoint value not when it exceeds the SetPoint value Here is a solution for an alternative Reset function Program inside PLC X X2 CTi Y1 Y y Counter CT1 CT1 SetPoint 8 O CTl x2 Current CTD1 In order to reset the counter the operator must press the Stop button
109. ting in an energized lamp Try duplicating this program in your own PLC even if it is a different brand or model and see how it functions Be sure to activate the color highlighting feature of your programming editor so you may see the live status of the program s virtual contacts and coil 24 This example shows a Siemens S7 200 series PLC model 224XP wired to two toggle switches and one LED indicator lamp complete with a demonstration program LED with dropping resistor CHTO SIEMENS EAE ERE EELE j SIMATIC AM 1L 00 O41 02 03 04 2M a 05 06 07 10 14 e m L D 7 200 CPU 224XP on0000000400 DC DC DC CI SF DIAG LOM t 92 Gaede Sh Gus 7a N L RUN L stop ROG 3 2 9 4 5 7 Ao al 22 9 eh 5 W OOOOOO00 10o00000 0 0 0 1 02 03 0 05 06 07 2M 10 11 12 13 14 15 M L Q Port 1 Port 0 Ladder Diagram program written to PLC TOTO Q0 0 END Note how Siemens I O is labeled in the program input bits designated by the letter I and output bits designated by the letter Q Based on the wiring and program you see for this PLC identify the switch state combinations resulting in an energized lamp Try duplicating this program in your own PLC even if it is a different brand or model and see how it functions Be sure to activate the color highlighting feature of your programming editor so you may see the live sta
110. 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 for 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 Duh 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 02DD1 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
111. tration of working system mastery Final PLC program inspection mastery o Lab question Wiring connections proportional Lab question Commissioning proportional u Lab question Mental math proportional S55 Lab question Diagnostics proportional eS 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 on a single day It is essential that your team plans ahead what to accomplish each day A short 10 minute team meeting at the beginning of each lab session is a good way to do this reviewing what s already been done what s left to do and what assessments you should be ready for There is a lot of work involved with building documenting and troubleshooting these working instrument systems As you and your team work on this system you will invariably encounter problems You should always attempt to solve these problems as a team before requesting instructor assistance If you still require instructor assistance write your team s color on the lab whiteboard with a brief description of what you need help on The instructor will meet with ea
112. ts such as terminal blocks in junction boxes between the field device and the controller You should practice good problem solving techniques when creating your prototype sketch such as consulting equipment manuals for information on component functions and marking directions of electric current voltage polarities and identifying electrical sources loads Use this task as an opportunity to strengthen your analytical skills Remember that you will be challenged in this program to do all of this on your own during capstone assessments so do not make the mistake of relying on your teammates to figure this out for you instead treat this as a problem you must solve and compare your results with those of your teammates Your team s prototype sketch is so important that the instructor will demand you provide this plan before any construction on your team s working system begins Any team found constructing their system without a verified plan will be ordered to cease construction and not resume until a prototype plan has been drafted and approved Similarly you should not deviate from the prototype design without instructor approval to ensure nothing will be done to harm equipment by 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 t
113. tus of the program s virtual contacts and coil 25 This example shows a Koyo CLICK PLC model C0 02DD1 D wired to two toggle switches and one LED indicator lamp complete with a demonstration program CLICK C0 02DD1 D Koyo PWR J RUN J ERR J LED with dropping resistor RUN PORT 1 1 CO RX1 LI TX2 LI RX2 LI PORT 2 PORT3 RS 485 T 3 LI RX3 CI LG S SS amp SSSSSSSSSSSSSS 24 VDC Ladder Diagram program written to PLC Wal KI 2 x2 7 END Note how Koyo I O is labeled in the program input bits designated by the letter X and output bits designated by the letter Y Based on the wiring and program you see for this PLC identify the switch state combinations resulting in an energized lamp Try duplicating this program in your own PLC even if it is a different brand or model and see how it functions Be sure to activate the color highlighting feature of your programming editor so you may see the live status of the program s virtual contacts and coil file 104513 26 Question 5 The most basic type of real world input to a PLC is a discrete on off input Each discrete input channel on a PLC is associated with a single bit in the PLC s memory Use the PLC programming software on your personal computer to connect to your PLC then locate the facility within this software that allows you to monitor the status of your PL
114. two process switches as shown in this illustration Slot 0 Slot 1 Slot 2 Slot 3 processor discrete input discrete input discrete output 120 VAC power Determine the bit statuses of I 1 3 and I 1 5 when the level switch senses 3 feet and the pressure switch senses 14 PSI file i04687 55 Question 33 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 instead 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 UL LL Warning siren Acknowledge pushbutton Alarm_input Blink Light k Latch Blink Latch Siren He H 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
115. ude the proper unit of measurement e g VA VAR or W with each answer P file 102422 94 Question 90 In this 480 volt AC induction motor control circuit sometimes referred to as a bucket a three pole relay typically called a contactor is used to switch power on and off to the motor The contactor itself is controlled by a smaller switch which receives 120 volts AC from a step down transformer to energize the contactor s magnetic coil Although this motor control circuit used to work just fine today the motor refuses to start To 3 480 volt power source Schematic diagram Transformer Transformer e Contactor Fuse Using your AC voltmeter you measure 476 volts AC between L1 and L2 477 volts AC between L2 and L3 and 475 volts AC between L1 and L3 You also measure 477 volts between transformer terminals H1 and H4 With the switch in the on position you measure 0 5 volts AC between terminals X1 and X2 on the transformer From this information identify the following e Two components or wires in the circuit that you know cannot be failed either open or shorted besides the 480 volt AC source which is obviously operational e Two different component or wire failures in the circuit either one of which could account for the problem and all measured values and the types of failures they would be either open or shorted file 103174 95 Question 91 Lab Exercise
116. with the word Demo and using underscore characters to separate descriptive words or instruction names in the rest of the filename Some examples are shown here Demo_contacts_coils Demo_upcounter Demo_downcounter Demo_TOF_timer Demo_TON_timer Demo_ADD_instruction file 100120 1141141 32 Question 11 All PLCs provide special locations in memory holding values useful to the programmer such as status warnings real time clock settings calendar dates etc Use the PLC programming software on your personal computer to connect to your PLC then locate the facility within this software that allows you to explore some of these locations in memory Identify some of the specific status related and special memory locations in your PLC and comment on those you think might be useful to use in the future Note the following memory types you may find associated with these addresses e Boolean discrete simply on or off 1 or 0 e Integer whole numbered values e Floating point real fractional values Suggestions for Socratic discussion e Describe some of the special memory locations you find in your search and comment on how some of them might be useful e One of the useful bits provided by many PLCs is a flashing bit that simply turns on and off at regular intervals How many of these bits can you find in your PLC s memory and how rapidly does each one oscillate
117. within the PLC s memory and enabling the user to force the values of those addresses Discrete outputs are the Q memory addresses e g Q0 4 Q1 2 etc e Koyo Automation Direct DirectLogic and CLICK the Override View window allows the user to force variables within the PLC s memory Discrete outputs are the Y memory addresses e g Y1 Y2 etc file 101877 28 Question 7 Read and outline the Relating I O Status to Virtual Elements subsection of the Logic Programming section of the Programmable Logic Controllers chapter in your Lessons In Industrial Instrumentation textbook Note the page numbers where important illustrations photographs equations tables and other relevant details are found Prepare to thoughtfully discuss with your instructor and classmates the concepts and examples explored in this reading The fundamental concept of relating I O status to program elements is not necessarily easy to grasp For this reason a Process Switches and PLC Circuits worksheet has been placed in the Socratic Instrumentation practice worksheet collection Feel free to use this practice worksheet to supplement your studies on this critically important topic file 104516 Question 8 Analyze the status of all relay contacts and lamps in this hard wired relay ladder logic control circuit Li IOVAC PBNO A CRI l Pressure switch Selector switch A Right e e CR2
118. 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 file 102664 68 Question 47 Demonstration Program counter 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 Th
119. zed 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 insert 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 101 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 i

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