Trend analysis and reporting in SCADA systems - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Identify the output of a trend data query command

You run the command to fetch temperature trends for the last hour in a SCADA system:

scada-cli get-trend --tag temperature --duration 1h --format json

What is the expected output format?

SCADA systems

scada-cli get-trend --tag temperature --duration 1h --format json

A Error: Unknown command 'get-trend'

B temperature=22.5;22.7;22.9

C [{"timestamp": "2024-06-01T10:00:00Z", "value": 22.5}, {"timestamp": "2024-06-01T10:05:00Z", "value": 22.7}]

D <trend><point time="10:00">22.5</point></trend>

💡 Hint

The command requests JSON format output for trend data.

The command uses --format json, so the output is a JSON array of timestamped values.

🧠 Conceptual

intermediate

Understanding trend data aggregation intervals

In SCADA trend reporting, what does setting an aggregation interval to 15 minutes mean?

A The system collects data only once every 15 minutes.

B Data points are averaged or summarized every 15 minutes before reporting.

C The trend report shows exactly 15 data points regardless of duration.

D Data older than 15 minutes is automatically deleted.

💡 Hint

Aggregation means combining data over time periods.

Aggregation interval defines how raw data is grouped and summarized for reports.

🔀 Workflow

advanced

Order the steps to configure a new trend report in a SCADA system

Arrange these steps in the correct order to create a new trend report for pressure data:

A 3,1,2,4

B 2,1,3,4

C 1,3,2,4

D 1,2,3,4

💡 Hint

Start by selecting the data, then set time and aggregation before saving.

First select the tag, then time range, then aggregation, finally save and generate.

❓ Troubleshoot

advanced

Diagnose why a trend report shows no data

A trend report for flow rate shows no data for the last 24 hours. Which is the most likely cause?

A The flow rate tag is not configured to record historical data.

B The aggregation interval is set too low (e.g., 1 second).

C The report time range is set to future dates.

D The SCADA system is offline but still shows old data.

💡 Hint

Check if data is being recorded before reporting.

If the tag does not record history, no trend data will be available.

✅ Best Practice

expert

Choose the best practice for trend data retention policy

What is the best practice for setting a trend data retention policy in a SCADA system?

A Keep detailed raw data for a short period and aggregated summaries for longer periods.

B Store all raw data indefinitely without aggregation.

C Delete all trend data after 7 days to save storage.

D Only keep aggregated data and discard raw data immediately.

💡 Hint

Balance storage use and data detail over time.

Keeping raw data short-term and summaries long-term balances detail and storage.

Practice

1. What is the main purpose of trend analysis in SCADA systems?

easy

A. To configure hardware devices

B. To track changes in data over time

C. To write code for automation

D. To backup system files

Solution

1. Step 1: Understand trend analysis concept

   Trend analysis means observing how data changes over a period.

2. Step 2: Match purpose with options

   Only tracking data changes over time fits the definition of trend analysis.

3. Final Answer:

   To track changes in data over time -> Option B

4. Quick Check:

   Trend analysis = track data changes [OK]

Hint: Trend analysis = watching data over time [OK]

Common Mistakes:

• Confusing trend analysis with system backup
• Thinking it configures devices
• Mixing it with coding tasks

2. Which of the following is the correct command to generate a trend report in a SCADA system CLI?

easy

A. generate_trend_report --start 2024-01-01 --end 2024-01-31

B. trend report create start=2024-01-01 end=2024-01-31

C. create report trend from 2024-01-01 to 2024-01-31

D. report --trend --from 2024-01-01 --to 2024-01-31

Solution

1. Step 1: Identify correct command syntax

   SCADA CLI commands usually follow verb_action --option value format.

2. Step 2: Compare options

   generate_trend_report --start 2024-01-01 --end 2024-01-31 matches the expected syntax with clear flags and dates.

3. Final Answer:

   generate_trend_report --start 2024-01-01 --end 2024-01-31 -> Option A

4. Quick Check:

   Correct CLI syntax = generate_trend_report --start 2024-01-01 --end 2024-01-31 [OK]

Hint: Look for commands with clear flags and date ranges [OK]

Common Mistakes:

• Using incorrect command order
• Missing dashes before options
• Using natural language instead of CLI syntax

3. Given this snippet of a SCADA trend report script:

data = [10, 15, 20, 25, 30]
trend = []
for i in range(1, len(data)):
    trend.append(data[i] - data[i-1])
print(trend)

What is the output?

medium

A. [10, 5, 5, 5]

B. [10, 15, 20, 25, 30]

C. [5, 10, 15, 20]

D. [5, 5, 5, 5]

Solution

1. Step 1: Calculate differences between consecutive data points

   Subtract each previous value from current: 15-10=5, 20-15=5, 25-20=5, 30-25=5.

2. Step 2: Collect results in trend list and print

   The trend list is [5, 5, 5, 5], which is printed.

3. Final Answer:

   [5, 5, 5, 5] -> Option D

4. Quick Check:

   Differences between data points = [5,5,5,5] [OK]

Hint: Subtract previous from current values to find trend [OK]

Common Mistakes:

• Printing original data instead of differences
• Off-by-one errors in loop range
• Appending wrong values to trend list

4. You run this SCADA report command but get an error:

generate_trend_report --start 2024-02-30 --end 2024-03-01

What is the likely cause?

medium

A. End date is before start date

B. Missing required --format option

C. Invalid date: February 30 does not exist

D. Command syntax is incorrect

Solution

1. Step 1: Check date validity

   February has at most 29 days; 30 is invalid.

2. Step 2: Confirm error cause

   Invalid date causes command to fail before other checks.

3. Final Answer:

   Invalid date: February 30 does not exist -> Option C

4. Quick Check:

   Invalid date causes error [OK]

Hint: Verify dates exist on calendar before running commands [OK]

Common Mistakes:

• Assuming syntax error without checking dates
• Ignoring invalid date and blaming options
• Confusing start and end date order

5. You want to create a report showing average temperature trends per day from hourly SCADA data. Which approach is best?

hard

A. Aggregate hourly data by day, then calculate daily averages and plot trend

B. Plot hourly data directly without aggregation

C. Calculate weekly averages ignoring daily details

D. Use raw data without any calculations for reporting

Solution

1. Step 1: Understand goal of daily average trends

   We need daily summaries from hourly data to see daily trends clearly.

2. Step 2: Choose method to aggregate and analyze data

   Aggregating hourly data by day and calculating averages fits the goal best.

3. Final Answer:

   Aggregate hourly data by day, then calculate daily averages and plot trend -> Option A

4. Quick Check:

   Daily average trend needs daily aggregation [OK]

Hint: Group data by day before averaging for daily trends [OK]

Common Mistakes:

• Using raw hourly data without aggregation
• Skipping daily grouping and using weekly averages
• Ignoring calculations and plotting raw data