Navigation and screen hierarchy in SCADA systems - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the main screen in the SCADA system.

SCADA systems

main_screen = Screen(name=[1])

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

AmainScreen

BMainScreen

C'main_screen'

D"MainScreen"

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put quotes around the screen name

Using variable names without quotes

The screen name must be a string, so it needs to be enclosed in quotes.

2fill in blank

medium

Complete the code to add a child screen to the main screen.

SCADA systems

main_screen.add_child([1])

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

AchildScreen

B'childScreen'

Cchild_screen

D"ChildScreen"

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the screen name as a string instead of the screen object

Using quotes around the variable name

The add_child method expects a Screen object, so the variable name without quotes is correct.

3fill in blank

hard

Fix the error in the code to navigate to a screen by its name.

SCADA systems

navigate_to_screen([1])

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

A"screen_name"

Bscreen_name

CscreenName

D'screenName'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing variable names without quotes

Using single quotes instead of double quotes if the system requires double quotes

The function expects the screen name as a string, so it must be in quotes.

4fill in blank

hard

Fill both blanks to create a screen hierarchy with a parent and child screen.

SCADA systems

parent_screen = Screen(name=[1])
parent_screen.add_child([2])

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

A"ParentScreen"

Bchild_screen

C"ChildScreen"

DparentScreen

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names without quotes for screen names

Putting quotes around the child screen variable

The parent screen name must be a string, and the child screen is a variable passed without quotes.

5fill in blank

hard

Fill all three blanks to define a screen dictionary with screen names as keys and screen objects as values, filtering only active screens.

SCADA systems

active_screens = { [1]: [2] for [1] in screens if screens[[1]].[3] }

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

Ascreen_name

Bscreens[screen_name]

Cis_active

Dscreen

Attempts:

3 left

💡 Hint

Common Mistakes

Using inconsistent variable names for keys and values

Checking wrong attribute for active status

Use 'screen_name' as the key variable, 'screens[screen_name]' as the value, and check the 'is_active' attribute.

Practice

1. What is the main purpose of navigation and screen hierarchy in SCADA systems?

easy

A. To organize screens in a clear tree structure for easy access

B. To increase the number of screens in the system

C. To make screens load slower for security

D. To hide all screens from the user

Solution

1. Step 1: Understand navigation purpose

   Navigation helps users find screens quickly by organizing them logically.

2. Step 2: Understand screen hierarchy role

   Hierarchy arranges screens as parents and children, creating a clear structure.

3. Final Answer:

   To organize screens in a clear tree structure for easy access -> Option A

4. Quick Check:

   Navigation = Organize screens clearly [OK]

Hint: Think of folders organizing files for easy finding [OK]

Common Mistakes:

• Confusing more screens with better navigation
• Thinking navigation slows system
• Believing screens should be hidden

2. Which of the following is the correct way to define a parent-child relationship between screens in a SCADA configuration file?

easy

A. "ScreenA": { "children": ["ScreenB", "ScreenC"] }

B. "ScreenA": { "parent": ["ScreenB", "ScreenC"] }

C. "ScreenA": { "siblings": ["ScreenB", "ScreenC"] }

D. "ScreenA": { "children": "ScreenB", "ScreenC" }

Solution

1. Step 1: Identify correct syntax for children

   Children are listed as an array under the key "children" for a parent screen.

2. Step 2: Check options for correct JSON structure

   "ScreenA": { "children": ["ScreenB", "ScreenC"] } uses an array correctly; others misuse keys or syntax.

3. Final Answer:

   "ScreenA": { "children": ["ScreenB", "ScreenC"] } -> Option A

4. Quick Check:

   Children = array under "children" key [OK]

Hint: Children screens go inside a list under "children" [OK]

Common Mistakes:

• Using "parent" key to list children
• Listing children without brackets
• Using "siblings" key incorrectly

3. Given this screen hierarchy configuration snippet:

{
  "MainScreen": { "children": ["AlarmScreen"] },
  "AlarmScreen": { "children": ["DetailScreen"] },
  "DetailScreen": {}
}

What is the correct navigation path to reach DetailScreen starting from MainScreen?

medium

A. MainScreen > DetailScreen > AlarmScreen

B. DetailScreen > AlarmScreen > MainScreen

C. AlarmScreen > MainScreen > DetailScreen

D. MainScreen > AlarmScreen > DetailScreen

Solution

1. Step 1: Read the hierarchy from the configuration

   MainScreen has AlarmScreen as child; AlarmScreen has DetailScreen as child.

2. Step 2: Trace the path from MainScreen to DetailScreen

   Navigate MainScreen to AlarmScreen, then AlarmScreen to DetailScreen.

3. Final Answer:

   MainScreen > AlarmScreen > DetailScreen -> Option D

4. Quick Check:

   Parent to child order = MainScreen > AlarmScreen > DetailScreen [OK]

Hint: Follow children arrays step-by-step [OK]

Common Mistakes:

• Reading hierarchy backwards
• Skipping intermediate screens
• Mixing order of screens

4. You have this incorrect screen hierarchy configuration:

{
  "MainScreen": { "children": "AlarmScreen" },
  "AlarmScreen": { "children": ["DetailScreen"] }
}

What is the main error and how to fix it?

medium

A. DetailScreen should be a child of MainScreen directly

B. Children key should be "parent" instead

C. Children must be a list; change "children": "AlarmScreen" to "children": ["AlarmScreen"]

D. Remove the children key from AlarmScreen

Solution

1. Step 1: Identify data type error in children key

   Children must be a list (array), but "AlarmScreen" is a string here.

2. Step 2: Correct the children value to a list

   Wrap "AlarmScreen" in brackets to make it a list: ["AlarmScreen"].

3. Final Answer:

   Children must be a list; change "children": "AlarmScreen" to "children": ["AlarmScreen"] -> Option C

4. Quick Check:

   Children = list, not string [OK]

Hint: Children always use square brackets [] [OK]

Common Mistakes:

• Using string instead of list for children
• Confusing children with parent key
• Changing unrelated keys

5. You want to design a SCADA screen hierarchy where MainScreen has two children: AlarmScreen and StatusScreen. AlarmScreen further has a child DetailScreen. Which JSON configuration correctly represents this hierarchy?

hard

A. {
"MainScreen": { "children": ["DetailScreen"] },
"AlarmScreen": { "children": ["StatusScreen"] },
"StatusScreen": {},
"DetailScreen": {}
}

B. {
"MainScreen": { "children": ["AlarmScreen", "StatusScreen"] },
"AlarmScreen": { "children": ["DetailScreen"] },
"StatusScreen": {},
"DetailScreen": {}
}

C. {
"MainScreen": { "children": ["AlarmScreen"] },
"AlarmScreen": { "children": ["StatusScreen", "DetailScreen"] },
"StatusScreen": {}
}

D. {
"MainScreen": { "children": ["StatusScreen"] },
"AlarmScreen": { "children": ["DetailScreen"] },
"StatusScreen": {},
"DetailScreen": {}
}

Solution

1. Step 1: Check MainScreen children

   MainScreen must have AlarmScreen and StatusScreen as children; only { "MainScreen": { "children": ["AlarmScreen", "StatusScreen"] }, "AlarmScreen": { "children": ["DetailScreen"] }, "StatusScreen": {}, "DetailScreen": {} } matches this.

2. Step 2: Check AlarmScreen children

   AlarmScreen must have DetailScreen as child; { "MainScreen": { "children": ["AlarmScreen", "StatusScreen"] }, "AlarmScreen": { "children": ["DetailScreen"] }, "StatusScreen": {}, "DetailScreen": {} } correctly shows this.

3. Step 3: Verify other screens

   StatusScreen and DetailScreen have empty children, which is correct.

4. Final Answer:

   { "MainScreen": { "children": ["AlarmScreen", "StatusScreen"] }, "AlarmScreen": { "children": ["DetailScreen"] }, "StatusScreen": {}, "DetailScreen": {} } -> Option B

5. Quick Check:

   MainScreen children = AlarmScreen, StatusScreen; AlarmScreen child = DetailScreen [OK]

Hint: Match parent children exactly as arrays in JSON [OK]

Common Mistakes:

• Mixing children between screens
• Omitting children arrays
• Assigning wrong children to parents