💡 Extending the concept of hourly averages to shorter time intervals
📎 Related post: Calculations of hourly average consumption values

📌 Background

In process industries, consumption monitoring of resources such as steam, water, electricity, and compressed air is key to ensuring energy efficiency and sustainable operations. While hourly averages provide a solid overview, shorter intervals like 30 minutes can deliver even more granular insights—especially for fast-changing processes or detailed performance analysis.

👉 In some cases, half-hourly averages are required for regulatory reporting, for example to comply with environmental or energy-related limits imposed by authorities. Having these values available ensures transparency and compliance.

🎯 Challenge

How can we calculate average consumption values for fixed 30-minute intervals and distinguish them from rolling values? And how can we ensure the values are visualized cleanly as stepwise changes in the trend?

🛠️ Solution

✅ Rolling 30-minute average

This can be done easily using the Aggregation in the Tag Builder:

• Select your consumption signal (e.g., flow or energy).

• Choose the average operator.

• Set the direction to backward.

• Define a 30-minute aggregation window.

• Save the new tag.

This tag will always reflect the average of the past 30 minutes at any given time — ideal for real-time monitoring.

⏱️ Fixed 30-minute average

To represent fixed 30-minute average consumption values in a stepwise format (e.g., for regulatory reporting purposes), a custom formula is used in the Tag Builder. This ensures a new value appears precisely at the half-hour mark and remains constant for the next 30 minutes.

The logic builds upon shifted versions of the TM_hour_time zone tag to identify the exact transition points between 30-minute intervals.

🧮 Formula:

if(and(a<>c, a=b), AGGREGATION_1,
  if(and(a<>d, a=c, a<>f), AGGREGATION_2,
    if(and(a<>e, a=c, a<>g), AGGREGATION_1,
      if(and(a<>b, a=c), AGGREGATION_2, sqrt(-1)))))

🔄 Variable Mapping:

• a = TM_hour_time zone
• b = a shifted by +1s
• c = a shifted by -1s
• d = a shifted by +30m 1s
• e = a shifted by +30m
• f = a shifted by -30m
• g = a shifted by -30m 1s
• AGGREGATION_1 = aggregation above
• AGGREGATION_2 = AGGREGATION_1 shifted by -29m 59s

The sqrt(-1) trick is used to enforce interpolation between steps where no fixed value should be shown. The result is a new tag that shows a constant average value for each 30-minute interval, updating exactly at the boundaries.

✅ Value

These new 30-minute tags—both rolling and fixed—offer a powerful way to:

• Monitor short-term fluctuations.

• Detect inefficiencies faster.

• Provide more detailed insights for shift handovers or rapid diagnostics.

• Integrate into energy dashboards or set smart alerts.

Would you like to try it out? ✨
👉 Share your experiences or ask questions in the comments!