Conveyor sorting system in PLC Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the conveyor motor when the start button is pressed.

PLC Programming

IF StartButton = TRUE THEN
    ConveyorMotor := [1];
END_IF;

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

AON

BOFF

CSTOP

DRESET

Attempts:

3 left

💡 Hint

Common Mistakes

Using OFF instead of ON to start the motor.

Confusing STOP with turning the motor ON.

The conveyor motor should be turned ON when the start button is pressed.

2fill in blank

medium

Complete the code to stop the conveyor motor when the stop button is pressed.

PLC Programming

IF StopButton = TRUE THEN
    ConveyorMotor := [1];
END_IF;

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

ASTART

BRESET

CRUN

DOFF

Attempts:

3 left

💡 Hint

Common Mistakes

Using START or RUN instead of OFF to stop the motor.

Confusing RESET with stopping the motor.

The conveyor motor should be turned OFF when the stop button is pressed.

3fill in blank

hard

Fix the error in the code to activate the sorting arm when an item is detected.

PLC Programming

IF ItemSensor = TRUE THEN
    SortingArm := [1];
END_IF;

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

ADEACTIVATE

BACTIVATE

COFF

DSTOP

Attempts:

3 left

💡 Hint

Common Mistakes

Using OFF or DEACTIVATE instead of ACTIVATE.

Confusing STOP with activating the arm.

The sorting arm should be ACTIVATED when an item is detected by the sensor.

4fill in blank

hard

Fill both blanks to check if the conveyor is running and the emergency stop is not pressed.

PLC Programming

IF ConveyorMotor = [1] AND EmergencyStop = [2] THEN
    SystemStatus := 'Running';
END_IF;

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

AON

BFALSE

CTRUE

DOFF

Attempts:

3 left

💡 Hint

Common Mistakes

Checking if EmergencyStop is TRUE instead of FALSE.

Using OFF for ConveyorMotor when it should be ON.

The conveyor motor should be ON and the emergency stop should be FALSE (not pressed) for the system to be running.

5fill in blank

hard

Fill all three blanks to create a dictionary that maps item colors to sorting bin numbers, only for bins greater than 0.

PLC Programming

SortingBins = { [1]: [2] for [1], [2] in ItemColors if [2] [3] 0 }

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

Acolor

Bbin_number

C>

Ditem

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'item' instead of 'color' as the key.

Using '<' instead of '>' in the condition.

The dictionary maps each color to its bin number, but only includes bins with numbers greater than 0.

Practice

1. In a conveyor sorting system, what is the main role of sensors?

easy

A. To power the entire system

B. To move the conveyor belt forward

C. To detect items and send signals for sorting decisions

D. To clean the conveyor belt automatically

Solution

1. Step 1: Understand sensor function in sorting

   Sensors detect the presence or type of items on the conveyor.

2. Step 2: Connect sensor signals to sorting

   The system uses sensor signals to decide where to send each item.

3. Final Answer:

   To detect items and send signals for sorting decisions -> Option C

4. Quick Check:

   Sensors detect items = C [OK]

Hint: Sensors detect items to guide sorting [OK]

Common Mistakes:

• Confusing sensors with motors
• Thinking sensors power the system
• Assuming sensors clean the belt

2. Which of the following is the correct syntax for a simple IF statement in PLC ladder logic to check if a sensor is ON?

easy

A. IF Sensor1 = TRUE THEN Conveyor := ON;

B. IF (Sensor1 == ON) { Conveyor = ON }

C. IF Sensor1 THEN Conveyor ON;

D. IF Sensor1 = ON THEN Conveyor := ON;

Solution

1. Step 1: Identify correct PLC syntax

   PLC languages often use ':=' for assignment and 'THEN' for conditions.

2. Step 2: Check sensor condition and assignment

   IF Sensor1 = TRUE THEN Conveyor := ON; uses 'Sensor1 = TRUE' and 'Conveyor := ON;' which matches PLC style.

3. Final Answer:

   IF Sensor1 = TRUE THEN Conveyor := ON; -> Option A

4. Quick Check:

   Correct PLC IF syntax = A [OK]

Hint: Look for ':=' assignment and 'THEN' keyword [OK]

Common Mistakes:

• Using '==' instead of '='
• Missing ':=' for assignment
• Using curly braces which are not PLC style

3. Given the following PLC code snippet for a conveyor sorting system:

IF SensorA = TRUE THEN
  Diverter := LEFT;
ELSE
  Diverter := RIGHT;
END_IF;

What will be the value of Diverter if SensorA is FALSE?

medium

A. LEFT

B. FALSE

C. TRUE

D. RIGHT

Solution

1. Step 1: Analyze the IF condition

   The code sets Diverter to LEFT if SensorA is TRUE.

2. Step 2: Determine ELSE action when SensorA is FALSE

   When SensorA is FALSE, Diverter is set to RIGHT.

3. Final Answer:

   RIGHT -> Option D

4. Quick Check:

   SensorA FALSE leads to Diverter RIGHT [OK]

Hint: FALSE condition triggers ELSE branch [OK]

Common Mistakes:

• Assuming Diverter stays unchanged
• Confusing TRUE and FALSE branches
• Mixing variable names

4. Identify the error in this PLC code snippet for sorting items:

IF Sensor1 = TRUE THEN
  Conveyor := ON
ELSE
  Conveyor := OFF;
END_IF;

medium

A. Missing semicolon after 'Conveyor := ON'

B. Incorrect use of ELSE statement

C. Sensor1 should be compared with FALSE

D. Assignment operator ':=' is invalid

Solution

1. Step 1: Check statement endings

   Each assignment line in PLC code must end with a semicolon.

2. Step 2: Locate missing semicolon

   The line 'Conveyor := ON' lacks a semicolon at the end.

3. Final Answer:

   Missing semicolon after 'Conveyor := ON' -> Option A

4. Quick Check:

   Semicolon missing = D [OK]

Hint: Check each line ends with semicolon [OK]

Common Mistakes:

• Ignoring semicolon errors
• Misreading ELSE syntax
• Thinking ':=' is wrong assignment

5. You want to program a conveyor sorting system that directs items to three paths: LEFT, CENTER, or RIGHT based on two sensors: SensorX and SensorY.

If SensorX is TRUE and SensorY is FALSE, send to LEFT.
If SensorX is FALSE and SensorY is TRUE, send to RIGHT.
Otherwise, send to CENTER.

Which PLC code snippet correctly implements this logic?

hard

A. IF SensorX = TRUE OR SensorY = FALSE THEN
Diverter := LEFT;
ELSEIF SensorX = FALSE OR SensorY = TRUE THEN
Diverter := RIGHT;
ELSE
Diverter := CENTER;
END_IF;

B. IF SensorX = TRUE AND SensorY = FALSE THEN
Diverter := LEFT;
ELSIF SensorX = FALSE AND SensorY = TRUE THEN
Diverter := RIGHT;
ELSE
Diverter := CENTER;
END_IF;

C. CASE
WHEN SensorX = TRUE AND SensorY = FALSE THEN Diverter := LEFT;
WHEN SensorX = FALSE AND SensorY = TRUE THEN Diverter := RIGHT;
ELSE Diverter := CENTER;
END_CASE;

D. IF SensorX = TRUE THEN
Diverter := LEFT;
ELSEIF SensorY = TRUE THEN
Diverter := RIGHT;
ELSE
Diverter := CENTER;
END_IF;

Solution

1. Step 1: Match conditions to logic

   IF SensorX = TRUE AND SensorY = FALSE THEN
     Diverter := LEFT;
   ELSIF SensorX = FALSE AND SensorY = TRUE THEN
     Diverter := RIGHT;
   ELSE
     Diverter := CENTER;
   END_IF;

   uses AND to check both sensors exactly as required.

2. Step 2: Verify ELSEIF and ELSE branches

   IF SensorX = TRUE AND SensorY = FALSE THEN
     Diverter := LEFT;
   ELSIF SensorX = FALSE AND SensorY = TRUE THEN
     Diverter := RIGHT;
   ELSE
     Diverter := CENTER;
   END_IF;

   correctly uses ELSIF for second condition and ELSE for default.

3. Step 3: Check other options for errors

   IF SensorX = TRUE OR SensorY = FALSE THEN
     Diverter := LEFT;
   ELSEIF SensorX = FALSE OR SensorY = TRUE THEN
     Diverter := RIGHT;
   ELSE
     Diverter := CENTER;
   END_IF;

   uses OR incorrectly, C uses CASE but syntax is not standard PLC, D misses combined conditions.

4. Final Answer:

   The code snippet with AND conditions -> Option B

5. Quick Check:

   Correct AND conditions and ELSIF = A [OK]

Hint: Use AND for combined sensor checks, ELSIF for second condition [OK]

Common Mistakes:

• Using OR instead of AND for combined conditions
• Incorrect CASE syntax in PLC
• Missing combined sensor checks