Data conversion instructions in PLC Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to convert an integer to a real number.

PLC Programming

REAL_Value := [1](INT_Value);

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

AINT_TO_REAL

BREAL_TO_INT

CTO_STRING

DBOOL_TO_INT

Attempts:

3 left

💡 Hint

Common Mistakes

Using REAL_TO_INT which converts in the opposite direction.

Using TO_STRING which converts to text, not numbers.

Use INT_TO_REAL to convert an integer value to a real (floating point) value.

2fill in blank

medium

Complete the code to convert a real number to an integer.

PLC Programming

INT_Value := [1](REAL_Value);

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

AREAL_TO_INT

BINT_TO_REAL

CSTRING_TO_INT

DBOOL_TO_REAL

Attempts:

3 left

💡 Hint

Common Mistakes

Using INT_TO_REAL which converts in the wrong direction.

Using STRING_TO_INT which expects a string input.

Use REAL_TO_INT to convert a real number to an integer by truncating the decimal part.

3fill in blank

hard

Fix the error in the code to convert a boolean to an integer.

PLC Programming

INT_Value := [1](BOOL_Value);

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

AREAL_TO_INT

BINT_TO_BOOL

CBOOL_TO_INT

DSTRING_TO_BOOL

Attempts:

3 left

💡 Hint

Common Mistakes

Using INT_TO_BOOL which converts in the opposite direction.

Using STRING_TO_BOOL which is unrelated here.

Use BOOL_TO_INT to convert a boolean value (TRUE/FALSE) to integer (1/0).

4fill in blank

hard

Fill both blanks to convert a string to a real number and then to an integer.

PLC Programming

REAL_Value := [1](String_Value);
INT_Value := [2](REAL_Value);

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

ASTRING_TO_REAL

BREAL_TO_INT

CINT_TO_REAL

DSTRING_TO_INT

Attempts:

3 left

💡 Hint

Common Mistakes

Using STRING_TO_INT directly which may fail if string is not integer format.

Using INT_TO_REAL which converts in the wrong direction.

First convert string to real with STRING_TO_REAL, then convert real to int with REAL_TO_INT.

5fill in blank

hard

Fill all three blanks to create a dictionary mapping string keys to integer values, filtering only keys with length greater than 3.

PLC Programming

Dict_Result := { [1]: [2] for [3] in String_List if LEN([3]) > 3 };

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

Akey

BSTRING_TO_INT(key)

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'value' as loop variable which is undefined.

Not converting string to int for dictionary values.

Use 'key' as dictionary key, convert it to int for value, and iterate with 'key' over String_List.

Practice

1. What is the main purpose of data conversion instructions in PLC programming?

easy

A. To create new variables automatically

B. To speed up the PLC scan time

C. To change data types so PLCs can process them correctly

D. To reset the PLC program

Solution

1. Step 1: Understand data conversion instructions

   Data conversion instructions change one data type to another so the PLC can handle the data properly.

2. Step 2: Identify the main purpose

   The main goal is to ensure data compatibility during processing or display.

3. Final Answer:

   To change data types so PLCs can process them correctly -> Option C

4. Quick Check:

   Data conversion = change data types [OK]

Hint: Data conversion = changing data types for compatibility [OK]

Common Mistakes:

• Thinking it speeds up the PLC scan
• Confusing with variable creation
• Assuming it resets the program

2. Which of the following is the correct syntax to convert an integer to a real number in a typical PLC program?

easy

A. INT_TO_REAL(value)

B. REAL(value)

C. TO_REAL(value)

D. CONVERT_REAL(value)

Solution

1. Step 1: Recall standard PLC conversion functions

   Most PLCs use functions like INT_TO_REAL to convert integers to real numbers.

2. Step 2: Match syntax options

   INT_TO_REAL(value) is the standard and correct syntax for this conversion.

3. Final Answer:

   INT_TO_REAL(value) -> Option A

4. Quick Check:

   Integer to real = INT_TO_REAL() [OK]

Hint: Look for function names starting with source type + _TO_ + target type [OK]

Common Mistakes:

• Using generic names like REAL(value)
• Assuming TO_REAL is standard
• Using CONVERT_REAL which is not typical

3. Given the following PLC code snippet:

INT_VAR := 1234;
REAL_VAR := INT_TO_REAL(INT_VAR);
INT_CONV := REAL_TO_INT(REAL_VAR);

What is the value of INT_CONV after execution?

medium

A. 1235

B. 1234

C. 1233

D. 0

Solution

1. Step 1: Convert INT_VAR to REAL_VAR

   INT_VAR is 1234, converted to real: REAL_VAR = 1234.0 (no change in value, just type).

2. Step 2: Convert REAL_VAR back to INT_CONV

   REAL_TO_INT(1234.0) converts back to integer 1234 without loss.

3. Final Answer:

   1234 -> Option B

4. Quick Check:

   Conversion back and forth keeps value same [OK]

Hint: Converting int to real and back keeps original integer value [OK]

Common Mistakes:

• Assuming rounding changes value
• Thinking conversion truncates incorrectly
• Confusing data types with values

4. Identify the error in this PLC code snippet:

REAL_VAR := 12.7;
INT_VAR := REAL_TO_INT(REAL_VAR);
BOOL_VAR := INT_TO_BOOL(REAL_VAR);

medium

A. REAL_VAR should be integer type

B. REAL_TO_INT cannot convert real to int

C. Missing semicolon after first line

D. INT_TO_BOOL cannot convert REAL directly

Solution

1. Step 1: Check each conversion

   REAL_TO_INT(REAL_VAR) is valid to convert real to int.

2. Step 2: Check INT_TO_BOOL(REAL_VAR)

   INT_TO_BOOL expects an integer input, but REAL_VAR is real type, causing an error.

3. Final Answer:

   INT_TO_BOOL cannot convert REAL directly -> Option D

4. Quick Check:

   Conversion functions require correct input types [OK]

Hint: Check input type matches conversion function parameter [OK]

Common Mistakes:

• Assuming all conversions accept any type
• Ignoring type mismatch errors
• Thinking missing semicolon causes conversion error

5. You have a PLC program that reads a sensor value as a 16-bit integer but needs to display it as a floating-point number with two decimal places. Which sequence of data conversion instructions is best to achieve this?

hard

A. INT_TO_REAL(sensor_value) then multiply by 0.01

B. REAL_TO_INT(sensor_value) then divide by 100

C. INT_TO_BOOL(sensor_value) then convert to REAL

D. BOOL_TO_INT(sensor_value) then multiply by 100

Solution

1. Step 1: Convert integer sensor value to real

   Use INT_TO_REAL to convert the 16-bit integer to a floating-point number.

2. Step 2: Adjust scale for decimal places

   Multiply the real number by 0.01 to shift decimal two places for display.

3. Final Answer:

   INT_TO_REAL(sensor_value) then multiply by 0.01 -> Option A

4. Quick Check:

   Convert int to real, then scale for decimals [OK]

Hint: Convert int to real first, then scale for decimals [OK]

Common Mistakes:

• Trying to convert real to int first
• Using boolean conversions incorrectly
• Multiplying before converting data type