Would like part A and part B of plc assignment completed please
School of Engineering
300044 Microcontrollers and PLCs
2020 PLC Major Assignment
Due: 11pm Sunday 1/11/2020, week 15
Find below the take home major assignment. It will count for 80% of your final assessment in the PLCs half of this unit.
The assignment can be done either individually or with a partner. If you are choosing a partner, make sure that you choose someone who will do a similar amount of work as you do. If you can’t find a suitable partner, you are better to do the assignment on your own than to choose an unsuitable partner.
Once you have chosen a partner, you should email me and I will give you a unique step-action diagram to follow.
Your assignment includes a place to record how much of the work each person contributed.
Being a major assignment, your submission must be your own/ your team’s own work. I have ways to detect copying, and any evidence of copying may result in complete failure for the unit.
Make sure that you dont leave any copies of your program on the computers or in the memory of the PLC. Download a blank program into the PLC before leaving the room, or the following person might be able to steal your work. In such situations there is no way for me to establish that you were not guilty of copying.
The tutor and I won’t be able to give you any help with writing or debugging your programs; we can however still answer questions about the tutorial exercises.
You may consult books, lecture notes and computer help files if you want.
Read the instructions carefully and ask me about anything you don’t understand.
Consult vUWS and your email regularly as I may need to inform you of clarification to these instructions.
Submitting your Assignment
Details of how to submit your assignment will be advised on vUWS.
Marking:
Your mark will be primarily based on:
• Whether your program performs the required tasks (most important).
• How well your program is written.
• How easy to follow your ladder diagram is.
• How well your report is written and presented.
This task has four different parts, plus a report:
• Part A, Compulsory (out of 50 marks)
• Part B, Optional (out of 15 marks)
• Part C, Optional (out of 15 marks)
• Part D, Optional (out of 15 marks)
• The Report, Compulsory (out of 10 marks)
Parts B, C and D all build on Part A, and any one or more can be completed independently – for example you can do Part A plus Part C plus Part D, and skip part B. All parts use different combinations of button presses, so all parts you have attempted must be combined into a single program, and submitted as a single (.cxp) file.
The minimum requirement to pass, is a Part A program that runs well and is well written, plus a well written report.
However, I suggest that you do more parts as programs rarely run as well as you think they will, and this will give you a buffer. You should also aim for more than just a pass.
Even if you attempt everything and it is all perfect, the maximum mark will be capped at 100.
Be sure to indicate clearly which parts you have attempted, on the cover of your report and on your signed declaration sheet.
In previous years I have had people hand in programs that do nothing when downloaded and the start button is pressed. I don’t want to be forced to give such people zero, so keep an eye on your student email – I need to be able to contact you if your program does nothing.
If you are in this situation, you will be given one opportunity of a couple of hours to come in and fix your program. If you are able to fix it, I will mark it, but will deduct a mark penalty.
To prevent this from happening to you,
1. If you have something that runs, and decide to modify or improve it, save the working version under a different name first.
2. Before handing in your submission, find the best program which runs, double check it and make sure you submit that part only.
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The Task Part A, Compulsory (out of 50 marks)
1. Program the PLC to execute the attached Step Action Diagram.
2. When the program is first downloaded, the machine should wait for the green button to be pressed.
3. Once the green button is pressed, the machine should start from step number 1 and then proceed through steps 2,3,4,etc.
4. Make the program cycle through repeatedly, with a 1-second pause between each cycle.
5. If the black button is pressed and released while the machine is running, the machine winds down to stop at the end of the cycle it is on as the button is released.
6. If the red button is pressed while the machine is running or winding down, the machine undergoes an emergency stop at the end of its current step.
7. If the yellow button is pressed during an emergency stop, as it is released the machine gets reset and any extended cylinders are retracted in the order: cylinder 4, cylinder 3, cylinder 2, cylinder 1.
8. After being reset or wound down as described above (in points 7 and 5), if the green button is pressed, the machine restarts from step number 1, and behaves as described in point 3.
9. If the green button is pressed during an emergency stop, the machine returns to the mode it was in when the emergency stop was activated and resumes from the step it was up to.
10. Any button or combination of buttons not assigned a function, must do nothing if pressed.
Part B, Optional (out of 15 marks)
A part B submission must do everything a part A submission does.
In addition:
11. If on the most recent occasion that the green button was used to start the machine from step 1, a double click was used rather than a single click; steps 6, 7, 8, 9, 10, 11 and 12 are repeated twice during every cycle
12. This continues until the machine is next restarted from step 1, as described in points 3 and 8.
13. During this repeating steps operation, the buttons all function as described for regular running, in part A.
14. A double click is defined as the button being pressed twice in 0.5 seconds.
Part C, Optional (out of 15 marks)
A part C submission must do everything a part A submission does.
In addition:
15. If the black button is given a double click while the machine is running, the machine pauses and enters a counting mode at the end of the step it is on as the button is given the second click.
16. A double click is defined as the button being pressed twice in 0.5 seconds.
17. It is only possible to enter counting mode during regular running – not while winding down, or doing a repeat step operation.
18. This counting mode is indicated by cylinders 1, 2 and 4 being extended and cylinder 3 being retracted.
19. While in this counting mode, the machine counts the number of times the green, yellow, black and red buttons are pressed.
20. The counting mode ends and the machine resumes from the next step when any two buttons are pressed simultaneously. Upon leaving counting mode, the PLC should return to the mode it was in.
21. Simultaneously means that, after one button is pressed, a second button is pressed before the first is released. (Neither of these deactivating button presses is counted in the totals).
22. As the buttons used to cancel the counting mode are released, they should not perform any other function.
23. A value for a variable D, is calculated according to the formula on the page with your step action diagram.
24. If the counting mode has been used during the current cycle (and resulted in an even value for D), the machine pauses immediately after step 18.
25. During this pause, cylinder 1 is used to indicate the value of D. This is achieved by pulsing cylinder 1 in a 1-second cycle (0.5 sec extended and 0.5 sec retracted).
26. If pulsing is used, the 1 second pause between cycles (point 4) is replaced by a 1 second pause before the pulsing and another 1 second pause after the pulsing.
27. Counting mode must only be entered once during each cycle. Any subsequent attempts to active the counting mode during the same cycle must be ignored.
28. The black, yellow and green buttons do nothing during the pulsing period.
29. If the red button, is pressed during the pulsing, an emergency stop is executed, the pulsing is cancelled, all cylinders are retracted, and the machine is reset (ready to be restarted as described in point 3).
Part D, Optional (out of 15 marks)
A part D submission must do everything a part C submission does.
In addition:
30. If part C has also been attempted, rather than point 29 under part C, the red button should activate a regular emergency stop if pressed during the extending and retracting period. This should happen at the end of the current extend or retract stroke. During such an emergency stop, the green, yellow and black buttons should behave as was described under part A.
31. In particular, if the green button is used to resume running, the extend/retract cycling should resume from where it was up to.
32. If the machine is running or winding down, and the yellow and black buttons are pressed simultaneously, the machine enters backward-wind-down mode.
33. Simultaneously means that, after one button is pressed, a second button is pressed before the first is released.
34. Backward-wind-down should not be activated if the machine is in repeat-steps mode as described in part B.
35. In backward-wind-down mode, the machine stops immediately at the end of the step it is on (as the second button is pressed), and then executes its steps in reverse, back to the start of the cycle, where it stops with all the cylinders retracted.
36. In addition, during backward-wind-down, the operation is delayed so that every step takes at least 0.5 seconds to complete:
for example, the time between the start of one step and the start of the following step must be:
? 0.5 seconds .
Time = the maximum of ??the time the step takes to complete
37. After a backward-wind-down is completed, if the green button is pressed, the machine restarts in the forward direction from step number 1 (as in point 3).
38. The green button, yellow buttons and the black buttons do nothing during backward-wind-down mode. Unless an emergency stop is activated.
39. If the red button is pressed while the machine is in the backward-wind- down mode, the machine undergoes an emergency stop as described under part A. The black, green and yellow buttons now behave as for other emergency stops (see part A).
40. As this cycle can never reach step 18 during backward-wind-down mode, the extend/retract cycling described in part C can never happen in this mode.
The Report, Compulsory (out of 10 marks):
Your report should include the following features:
* A description of what your program does.
* A print out of your ladder diagram.
* A table listing each input bit, output bit and work area bit, and what they are used for.
* A step action diagram as described in the lectures. Showing:
the PLC inputs, the PLC outputs, the essential inputs, and the bit addresses corresponding to each step.
• A mode table, as was described in the lectures.
