LO1 Describe the design and operational characteristics of a PLC system

 

Centre No: 04943

Technical Education Centre for Online Learning

Unit 15 Automation, PLCs, Robotics

Assessment Brief (Learner to fill in all parts highlighted in yellow)

Programme Title:	BTEC Level 4/5 Higher National Certificate / Diploma Engineering RQF General / Mechanical / Electrical & Electronic/ Manufacturing, Operations Engineering	Programme No:	HNC: L4E- ZTU 44/45/48, DCWP9/R1 HND: L4E- ZTU 46/47/50, DCWR2/R3
Unit Number and Title:	15: Automation, PLCs, Robotics	Edexcel Unit Code:	K/615/1489
Coursework Title:	Programmable Logic Controllers	Coursework Number:	H15A1
Date downloaded*		Duration (Weeks)	2 form + 3 sum.
Student Name		Assessor

 

LO No	Assessment learning outcomes covered	Formative Submission	Grade / Date Achieved
			Summative Submission	Resubmission
		Y/N?
01	Describe the design and operational characteristics of a PLC system
02	Design a simple PLC program by considering PLC information, programming and communication techniques
Scenario: You have been appointed as the project engineer for your company’s local site. The company’s aims to improve the automation process through the use PLCs and Robotic systems. Your initial focus is to look at automating material handling systems.
Evidence you must produce for this assignment: Answers written in your own words, with evidence such as appropriate written research work, program files and citation referencing.
Sources of information: Unit H15 course notes sections 1 and 2. Bolton, W. (2015) Programmable Logic Controllers Petruzella, F. (2017) Programmable Logic Controllers LOGO! Software | LOGO! Logic Module | Siemens Global - Demosoftware tab
Submission guidelines: Formative submission: Based on further guidance from Pearson; formative feedback will no longer give detailed feedback against each question part. Instead, we will indicate if your work is ‘on track’ and suitable for summative submission. Formative submission is optional; further details can be found in your HN learner handbook. The minimum requirement to obtain formative feedback shall be the submission of work within the duration period indicated above, otherwise the submission will be treated as summative feedback. (No copy of the assessment will be returned for this stage). *The duration period starts from the date of your download from Moodle. 2. Summative submission: Your assessor recommends that you now consider the formative feedback (if provided) as a way to best shape your work in preparation for your summative submission, which is normally 3 weeks after formative feedback has been provided. 3. Resubmission: The assessment board (at the discretion of the assessor) will permit only one opportunity to resubmit your summative submission if required, within 3 weeks of summative submission feedback. Note in this case the assessment grade will be capped at a maximum of pass grade if successful

Coursework Internal Verifier : Sign

Issue date (revision)

2/7/24 (r2024b)

Assessment Record Sheet

1. Learner to fill in on Formative submission:

Ref.	Evidence submitted (e.g. written report, calculation, file name).	Ref.		Evidence submitted (e.g. written report, calculation, file name).
Please carefully read the submission guideline 1, and you can also add additional comments here.
Learner Declaration on formative submission I certify that the evidence submitted for this assignment is my own. I have clearly referenced any sources used in the work. I understand that false declaration is a form of malpractice.			Learner Signature.		Date.
					02/07/2025

1. Assessor to fill in on Formative submission:

Formative feedback:
Has an extension to the deadline been approved by the Assessor due to extenuating circumstances?
Assessor Declaration on formative submission I certify that the evidence submitted for this assignment is the learner’s own. If it is not their own work, then this is clearly explained and detailed in the feedback and comments above	Assessor Signature.		Date.

2. Learner to fill in on Summative submission:

Ref.	Evidence submitted (e.g. written report, calculation, file name).	Ref.		Evidence submitted (e.g. written report, calculation, file name).
Please carefully read the submission guideline2, and you can also add additional comments here.
Learner Declaration on summative submission I certify that the evidence submitted for this assignment is my own. I have clearly referenced any sources used in the work. I understand that false declaration is a form of malpractice.			Learner Signature.		Date.

2. Assessor to fill in on Summative submission:

Ref.	Assessor comment on task(s)	Ref.		Assessor comment on task(s)
General feedback:
Assessor Declaration on summative submission I certify that the evidence submitted for this assignment is the learner’s own. If it is not their own work, then this is clearly explained and detailed in the feedback and comments above			Assessor Signature.		Date.

3. Learner to fill in on Resubmission:

Ref.	Evidence submitted (e.g. written report, calculation, file name).	Ref.		Evidence submitted (e.g. written report, calculation, file name).
Please carefully read the submission guideline 3, and you can also add additional comments here
Learner Declaration on resubmission I certify that the evidence submitted for this assignment is my own. I have clearly referenced any sources used in the work. I understand that false declaration is a form of malpractice.			Learner Signature.		Date.

3. Assessor to fill in on Resubmission:

Ref.	Assessor comment on task(s)	Ref.		Assessor comment on task(s)
General feedback:
Does the learner need to attempt an assessment Retake? Y/N					Date of Retake:
Assessor Declaration on resubmission I certify that the evidence submitted for this assignment is the learner’s own. If it is not their own work, then this is clearly explained and detailed in the feedback and comments above			Assessor Signature.				Date.

Sample Type: (First or resubmission)

Samples IV Signature:

Date:

 

Learning Outcomes and Assessment Criteria

LO1 Describe the design and operational characteristics of a PLC system

P1 Describe the key differences of PLC construction styles and their typical applications

P2 Determine the types of PLC input and output devices available

P3 Describe the different types of communication links used with PLCs

M1 Explain the different types of PLC programming languages available

D1 Analyse the internal architecture of a typical PLC to determine its operational applications

LO2 Design a simple PLC program by considering PLC information, programming and communication techniques

P4 Design and describe the preparation of a PLC software program

P5 Explain how communication connections are correctly used with the PLC

M2 Examine the methods, and programmed design elements, that have to be considered in the debugging and testing for the hardware used

D2 Produce all elements of a PLC program for a given industrial task and analyse its performance

Assessment Submission Guidelines:

Please follow the instructions listed on Moodle ensuring you avoid plagiarism and include cited referencing as per your HN referencing guide where appropriate. Assessment procedures are also detailed in HN learner handbook. As your study is on-line and is not classroom based, it is recommended that you submit a formative copy of your work after completing at least ‘part a’ of each activity, which will receive formative feedback advice but will not be graded.

Using the formative feedback provided, you can then proceed to submit your assessment for summative feedback and grading.  Part b fully develops the learning outcome and can be submitted at formative or summative stage.

ALL ANSWERS MUST BE YOUR OWN WORK

Part 1a) - Characteristics of a PLC system

A steel company is planning to automate various parts of its factory. One application is a simple automation of specific machines such as bar cutting with up to 10 I/Os, while the other application relates to a material sorting and handling conveyor system, that can support 4 cutting disk stations (1 station is shown below).

Considering unitary, and modular PLCs, you have been asked to select a real commercial PLC of each type that would be suitable each application and describe the following:

i. The construction and application for unitary and modular type of PLC selected for the steel company above (2 PLCs). Also highlight their differences.

ii. Investigate the I/O devices required for the system and provide details for the cutting and material handling applications (include images of theI/O devices). Also support your investigation with a summary table of the field devices including types (e.g proximity sensor, motor), signals (e.g. analogue/digital, voltage/current range) required.

iii. Ensuring the PLCs can be configurated to work together, draw an appropriate real network diagram that connects the 4 cutting disk station PLCs together to an overall conveyor. Also draw the field devices for at least 1 cutting disk PLC and the conveyor PLC and describe the communication links used in both diagrams.

Guidance: The conveyor or material handler PLC will be feeding the machine by sensing a stock of bars, drop them onto the bar cutter, and after cutting, weigh and move full boxes away and replace with empty boxes. The bar cutter starts when it senses a new bar on it bed, then will push and clamp the bar at a pre-set length, cut and push the bar into the box, and repeat a pre-set number of times. 1a(i) 2 PLC types and construction must be different (i.e. unitary – for cutting operations and modular- for moving handling pipes and communication with the 4 unitary PLCs) 1a(ii) provide commercial examples of devices. 1a(iii) ‘block’ diagram should show the physical layout and not the software. 1a(iii) should also include an appropriate commercial network example suitable for the selected PLCs as well as PLC to I/O communications. 1000-word written report with appropriate diagrams, commercial examples and cited references.

See https://new.siemens.com/global/en/products/automation/systems/industrial/plc/logo.html

Part 1b

I.  List the 4 different programming languages identified in IEC 61131-3 and write a short description of the advantages and disadvantages of each. Your answer should include a sample image example of each to highlight how they are presented to the user/programmer.

II. Function Block or Ladder Logic Diagrams were used in Task 2a below. Justify your choice of programming method for this application and use LOGO to display an image of the program in both formats, to aid your discussion.

III. Analyse the internal architecture of a commercial modular PLC (e.g. Siemens S7-1200), to determine its suitability for operational applications such as your example in task T1a(ii). Include analysis on PSU, memory, CPU, bus system, processing instructions, and I/O module types.

Guidance 1200 words written report with appropriate diagrams, commercial examples and cited references.

Part 2a - PLC programming and communication techniques

1. Design and write a program to implement the process illustrated in Figure 2a(i). An up-counter must be programmed as part of a batch-counting operation to sort parts automatically for quality control. The counter is installed to divert 1 part out of every 8 for quality control or inspection purposes.

The circuit operates as follows:

• When the Start ‘push to make’ (not toggle) switch (I1) is pressed/released, and gets latched on (B1: RS latch), the main conveyor line (Q1) will be energised, and parts will start to pass the proximity switch (B2) every 2 s
• The pulses generated by the proximity switch (B2: pulse generator) should be used to increment the quality check counter (B3). When the B3 = 4, the conveyor gate solenoid (Q2) will then activate for 1.5 s and the quality line conveyor (Q3) will run for 4 s to take a sample object
• The gate Q2 returns to its normal position when the 1.5 s time period ends, and the counter also resets back from 4 to 0. The main line Q1 does not stop (unless the stop is pressed)
• The process is repeated with a sample taken at every 4 object counts
• A reset ‘push to make’ (not toggle) switch (I2) is provided to reset the counter manually but not to stop the process.
• A stop ‘push to make’ (not toggle) switch (I3) is provided to stop the process at any time.
• The process should automatically reset and repeat until the stop switch is pressed

The design should include a flowchart of the process, and program written in LOGO using LLD or FBD

Fig 2a(i)

Guidance 2a(i):

• a commentary/label list of inputs, functions and outputs
• flow chart against the task’s circuit operation above and
• print-screens/image snips of key stages, showing the program operating correctly in the PLC simulator
• a separate copy of the LOGO program (do not embed)

1. With the aid of diagrams and examples, such as a conveyor system explain:

• the communication connections for Device-net and Profibus.
• how a distributive control differs from the supervisory control of a SCADA system?

Guidance 2a(ii): 600 word written report with appropriate diagrams, examples and cited references

Part 2b

1. Examine the methods, and programmed design elements, that have to be considered in the debugging and testing prior to hardware use.

2. Discuss the general steps should be followed when commissioning a PLC system.

Guidance T2b(i-ii) – 600 word written report (introduction, main body, conclusion) with appropriate cited references, diagrams and examples

Consider a chemical mixing application in a paint factory. Use LOGO to design and build the above system, using function block or ladder logic, which will control the operation as follows:

• When the ‘push to make’ Start (not toggle) switch (I1) is pressed/released, and gets latched on (B1: RS latch), the start ‘fill’ solenoid A (Q1) will be energised and the tank will start to fill.
• A flow meter 1 (B2: 1s pulse generator) can be used to increment the counter (B3: Up/down).
• Tank level full sensor switch indicator (Q2) can be activated when the counter function on = 8 (e.g. use on/off flag: M1) causing the fill solenoid A (Q1) to be shut-off
• When the tank is full, start the mixer motor (Q3) and run for 12 seconds (B4: off-delay timer).
• When the 12 seconds has expired, stop the mixer (Q3) and energise ‘empty’ solenoid B (Q4) until the tank is empty
• To monitor the tank emptying, pulses generated by a flow meter 2 (B5: 1s pulse generator) should be used to decrement the counter (B3: Up/down). 
• Tank empty can be detected using the empty sensor switch indicator (Q4) when the tank low level counter B3 function off = 1. (e.g. use on/off flag: M1)
• When the ‘push to make’ Stop button (I2) is operated, the process must stop immediately (Q5), but can continue from where it left off, when restarted (I1).
• The process should automatically reset and repeat until the stop switch is pressed

Test your LOGO build and comment on your testing using LOGO simulation mode. This requires at least 3 print-screens of testing the system using the LOGO simulator below at the filling, mixing and emptying stages.

Guidance T2b(iii) -print-screens/image snips of 3 key stages, showing with comments, the program operating correctly in the PLC simulator by including the simulator indicators as above. A copy of the LOGO program.

All ABout Unit 15 Automation, PLCs, Robotics

Unit 15 Automation, PLCs, Robotics focuses on the key principles of automation, Programmable Logic Controllers (PLCs), and robotic systems used in modern industries. This unit is designed to give students a hands-on understanding of how machines and systems can be automated to improve efficiency, safety, and accuracy in processes such as manufacturing, assembly, packaging, and more.

In this assignment, students are expected to learn how automation works, program and test PLCs, and understand how robots function in a real industrial environment. The goal is to develop both technical skills and a practical understanding of these technologies.

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Main Focus Areas of the Assignment

1. Automation Basics

You will begin by studying the concept of automation, which means using machines and systems to do tasks with little or no human input. This includes:

• Types of automation: fixed, programmable, and flexible

• Benefits of automation (e.g. faster production, cost savings, fewer errors)

• Real-life applications in sectors like automotive, food production, and logistics

2. Programmable Logic Controllers (PLCs)

A major part of this unit is focused on PLCs, which are small computers used to control machines. In this section of the assignment, you’ll learn:

• What a PLC is and how it works

• Different types of PLCs

• How to design, write, and test simple PLC programmes

• How PLCs are used to control lights, motors, sensors, etc.

• Using ladder logic diagrams (the standard way to program a PLC)

You might also be asked to create and explain your own PLC program, for example, to control a traffic light system or a bottle-filling machine.

3. Robotics in Automation

This part introduces you to robots used in automated systems, such as:

• Types of robots (e.g. arm robots, mobile robots, pick-and-place robots)

• Parts of a robot (sensors, actuators, joints, grippers)

• How robots are programmed

• Safety in robotic systems

• Typical tasks done by robots (e.g. welding, painting, assembling)

In the assignment, you may be required to:

• Study a robotic system used in a factory

• Explain how it works and what benefits it offers

• Compare robotic systems to manual or semi-automatic alternatives