Data quality flags in SCADA systems - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Data Quality Flags in SCADA Systems

What is the primary purpose of data quality flags in SCADA systems?

A To encrypt sensor data for secure transmission

B To prioritize which sensors send data first

C To control the frequency of data collection from sensors

D To indicate the reliability or validity of sensor data readings

💡 Hint

Think about how operators know if a sensor reading can be trusted.

Data quality flags mark sensor readings to show if they are valid, suspect, or invalid, helping operators trust the data.

💻 Command Output

intermediate

Interpreting Data Quality Flag Output

Given a SCADA system output showing a data quality flag value of 3 for a sensor reading, what does this typically mean?

A The sensor data is invalid or missing

B The sensor is offline and not sending data

C The sensor data is suspect or questionable

D The sensor data is valid and within normal range

💡 Hint

Flag values often use numbers to represent quality levels; 3 usually means suspect.

In many SCADA systems, a data quality flag of 3 indicates the data is suspect, meaning it may be inaccurate or questionable.

❓ Configuration

advanced

Configuring Data Quality Flags for Sensor Thresholds

Which configuration snippet correctly sets a data quality flag to 'invalid' when a temperature sensor reading exceeds 100°C in a SCADA system?

A

if temperature >= 100:
  data_quality_flag = 'suspect'

B

if temperature > 100:
  data_quality_flag = 'invalid'

C

if temperature > 100:
  data_quality_flag = 'valid'

D

if temperature < 100:
  data_quality_flag = 'invalid'

💡 Hint

Invalid flag should be set when temperature is above 100°C, not below.

The correct configuration sets the flag to 'invalid' when temperature exceeds 100°C, marking the data as unreliable.

❓ Troubleshoot

advanced

Troubleshooting Unexpected Data Quality Flags

A SCADA operator notices that many sensor readings are flagged as 'invalid' even though sensors appear to be working. What is the most likely cause?

A The data quality flag thresholds are set too strict or incorrectly

B The sensors are physically damaged and need replacement

C The network connection is too fast causing data loss

D The SCADA system is not receiving any data from sensors

💡 Hint

Check configuration settings before hardware issues.

Incorrect or overly strict thresholds for data quality flags can cause valid data to be marked invalid.

🔀 Workflow

expert

Data Quality Flag Handling Workflow

Arrange the steps in the correct order for handling sensor data with quality flags in a SCADA system.

A 1,2,3,4

B 2,1,3,4

C 1,3,2,4

D 1,2,4,3

💡 Hint

Think about the natural flow from data collection to usage.

The correct workflow is to first collect data, then evaluate it, assign flags, and finally use the flagged data for monitoring.