PLC program documentation standards in PLC Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a comment describing the purpose of the PLC program.

PLC Programming

// [1]: Controls the conveyor belt speed

Drag options to blanks, or click blank then click option'

AInitialize variables

BStart the motor

CProgram description

DMain control loop

Attempts:

3 left

💡 Hint

Common Mistakes

Using a comment that describes an action instead of the program purpose.

The comment should describe the program's purpose, so 'Program description' is correct.

2fill in blank

medium

Complete the code to add a header comment with the author's name.

PLC Programming

/* Author: [1] */

Drag options to blanks, or click blank then click option'

AJohn Doe

BVersion 1.0

CConveyor Control

D2024-01-01

Attempts:

3 left

💡 Hint

Common Mistakes

Putting a date or version number instead of the author's name.

The author's name should be placed after 'Author:' in the comment header.

3fill in blank

hard

Fix the error in the comment syntax to properly document the program version.

PLC Programming

// Version [1]

Drag options to blanks, or click blank then click option'

A"1.0"

Bv1

Cversion 1.0

D1.0

Attempts:

3 left

💡 Hint

Common Mistakes

Adding quotes or extra words inside the comment.

The version number should be a simple string without quotes in the comment.

4fill in blank

hard

Fill both blanks to document the input and output variables in the PLC program.

PLC Programming

// Input variable: [1]
// Output variable: [2]

Drag options to blanks, or click blank then click option'

AStartButton

BMotorSpeed

CConveyorBelt

DStopButton

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing input and output variables.

StartButton is an input, and MotorSpeed is an output variable in typical PLC programs.

5fill in blank

hard

Fill all three blanks to complete the documentation block with date, author, and description.

PLC Programming

/*
Date: [1]
Author: [2]
Description: [3]
*/

Drag options to blanks, or click blank then click option'

A2024-06-01

BAlice Smith

CControls the packaging line

DVersion 2.0

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the order of date, author, and description.

The date, author, and description should be placed in the respective fields in the comment block.

Practice

1. Why is it important to include documentation in a PLC program?

easy

A. It automatically fixes errors in the program.

B. It makes the program run faster.

C. It reduces the size of the program file.

D. It helps others understand and maintain the program easily.

Solution

1. Step 1: Understand the purpose of documentation

   Documentation explains the program's purpose and logic to others.

2. Step 2: Identify benefits of documentation

   It helps maintain and update the program without confusion.

3. Final Answer:

   It helps others understand and maintain the program easily. -> Option D

4. Quick Check:

   Documentation improves understanding = A [OK]

Hint: Documentation = easier understanding and maintenance [OK]

Common Mistakes:

• Thinking documentation speeds up program execution
• Assuming documentation reduces program size
• Believing documentation fixes errors automatically

2. Which of the following is the correct way to add a comment in a PLC program?

easy

A. (* This is a comment *)

B. # This is a comment

C. // This is a comment

D.

Solution

1. Step 1: Identify comment syntax in PLC programming

   Many PLC languages use (* ... *) for comments.

2. Step 2: Compare options

   // is for C-like languages, # for scripting, for HTML, so only (* ... *) fits PLC.

3. Final Answer:

   (* This is a comment *) -> Option A

4. Quick Check:

   PLC comments use (* ... *) = C [OK]

Hint: PLC comments use (* and *) symbols [OK]

Common Mistakes:

• Using // or # which are not standard in PLC
• Confusing HTML comments with PLC comments
• Leaving out comment delimiters

3. Given this comment in a PLC program: (* Input: Start button, Output: Motor *), what is the main purpose of this comment?

medium

A. To optimize the motor control logic.

B. To execute the motor when the start button is pressed.

C. To describe the program's inputs and outputs clearly.

D. To declare variables for the start button and motor.

Solution

1. Step 1: Read the comment content

   The comment states inputs and outputs: Start button and Motor.

2. Step 2: Understand comment purpose

   Comments explain code parts, not execute or declare variables.

3. Final Answer:

   To describe the program's inputs and outputs clearly. -> Option C

4. Quick Check:

   Comments explain inputs/outputs = D [OK]

Hint: Comments explain, not execute or declare [OK]

Common Mistakes:

• Thinking comments run code
• Confusing comments with variable declarations
• Assuming comments optimize logic

4. A PLC program has this comment: (* Author: John Doe Purpose: Control conveyor speed *) but it is missing input and output details. What is the best fix?

medium

A. Remove the author name to save space.

B. Add comments describing inputs and outputs clearly.

C. Delete the comment because it is incomplete.

D. Add code to automatically generate comments.

Solution

1. Step 1: Identify missing documentation parts

   The comment lacks input and output descriptions which are important.

2. Step 2: Choose the best way to improve documentation

   Adding clear input/output comments improves understanding and maintenance.

3. Final Answer:

   Add comments describing inputs and outputs clearly. -> Option B

4. Quick Check:

   Complete comments include inputs/outputs = B [OK]

Hint: Complete comments include inputs and outputs [OK]

Common Mistakes:

• Removing author info unnecessarily
• Deleting useful comments
• Expecting code to auto-generate comments

5. You need to document a complex PLC program controlling multiple machines. Which approach best follows PLC program documentation standards?

hard

A. Write clear comments for each machine's inputs, outputs, logic, and author info.

B. Write one long comment at the start describing the whole program.

C. Skip comments to avoid clutter and rely on variable names only.

D. Use technical jargon to impress other engineers.

Solution

1. Step 1: Understand documentation needs for complex programs

   Complex programs need clear, organized comments for each part.

2. Step 2: Evaluate options for clarity and standards

   Clear comments per machine with inputs, outputs, logic, and author info follow best practices.

3. Final Answer:

   Write clear comments for each machine's inputs, outputs, logic, and author info. -> Option A

4. Quick Check:

   Clear, organized comments = A [OK]

Hint: Document each part clearly with inputs, outputs, logic [OK]

Common Mistakes:

• Writing only one big comment
• Skipping comments entirely
• Using confusing technical jargon