Trend Collectors

Trend Collectors allow you to store historic telemetry readings for equipment, sensors, and devices in your building. You can use trend data in equipment plots, reports, and charts to evaluate equipment performance and troubleshoot sequence and operation issues. You can also query trend data using the Green Stack REST API and export historic data for use in other platforms.

Trend Collector Types

Trend Collectors can be configured as one of two types: Edge Polling or Manual Upload

Edge Polling

Edge Polling type collectors are synchronized with an edge device that queries the target point at the desired sample interval and uploads readings to the cloud in real time. To use Edge Polling, the target point must be connected via an active Green Stack edge device with BACnet configured.

Edge Polling collectors store the following data properties with each sample:

  • Present Value (raw integer)

  • Feedback Value (raw integer, if present)

  • Status Flags

  • Event State

  • Priority Array

  • State Text

Manual Upload

Manual Upload type collectors are simple data buckets that accept user-uploaded CSV sample data. These collectors are useful if you are exporting trend data directly from a building automation system and they allow you to add historic reporting when you don't have an active edge device.

Trend Collector Quality

Trend Collector data quality is an indicator of collector and system health. The data quality of a trend collector is determined by calculating the number of data samples that are missing for a given time period and is expressed as a percentage. The higher the percentage, the healthier the collector.

For example, in a two-hour period, a trend collector with a five-minute sample interval should receive 24 data samples. If only 18 samples have been collected, the data quality will be 75% and the collector will be considered unhealthy.

Automatic Quality Monitoring

Green Stack Cloud constantly evaluates the sample quality of polled trend collectors over a rolling two-hour period. When more than 15% of samples are missing over the last two hours, the collector will be marked as UNHEALTHY. When the missing sample rate drops below 15%, the collector will be marked as HEALTHY again.

You can review collector health change events in the System Activity Log.

Note, data quality monitoring is only available for Edge Polling-type collectors

Manage Trend Collectors

Trend Collectors are managed in Building Engineering on a site-by-site basis. To view and manage Trend Collectors in the Green Stack Console:

  1. Log in to the Green Stack Console and navigate to Building Engineering

  2. Select a site from the system tree

  3. Select Trend Collectors

Add a New Trend Collector

To add a new Trend Collector:

  1. Click New Collector

  2. Select the desired Target Point

  3. Select the desired Collection Strategy (see above)

  4. Select the desired Sample Cadence (interval)

  5. Click Add Collector to save the collector

Note, once a trend collector is created, the target point and the sample cadence cannot be changed

Manage Existing Trend Collectors

To manage existing Trend Collectors, select its name from the list.

Viewing Sample Data

You can view the collected sample data for a collector on the Samples tab. Use the Duration dropdown to shift the sample window as desired.

Toggle Data Collection

To disable/enable data collection:

  1. Click Configure Collector

  2. Toggle Data Collection as desired

Data collection can only be disabled for Edge Polling-type collectors

Manual Sample Upload

You can manually upload trend sample data using a prepared CSV with the following columns:

  • timestamp

  • value

  • feedback_value

Note, Status Flags, Event State, and Priority Array are not available for manual upload-type collectors

To manually upload trend collector sample data:

  1. Select a Manual Upload trend collector from the list

  2. Click the Samples tab

  3. Click Upload Samples to open the Sample Upload Wizard

  4. Select the target CSV data file

  5. Adjust the UTC Offset as needed

  6. Click Upload & Review to pre-process the sample data

  7. Review the sample data and click Commit Samples

  8. Click Close to finish the wizard

Duplicate Sample Behavior

When performing a manual data upload, the system discards sample data that already exists. This behavior prevents data from accidentally being overwritten when it has already been uploaded.

Delete a Trend Collector

To delete an existing trend collector:

  1. Select the checkbox next to one or more Trend Collectors in the list

  2. Click the Trash Can icon

  3. Confirm the delete

Trend Collector deletions are irreversible, and all collector samples will be lost forever!

Troubleshooting Trend Collectors

Healthy, well-maintained trend collectors are a crucial component of a holistic building engineering strategy. Ensuring your trend collectors remain healthy is vital for the ongoing health of your building.

When troubleshooting collector quality, ensure:

  • The target edge device is online

  • The target BMS device is online

  • The target BMS point exists in the device database

Edge devices log collector issues as they arise. When troubleshooting collectors, you can check edge device logs to narrow down a polling or device issue on-site.

Transient data quality issues may arise when an edge device loses connection to the internet. In these situations, the edge device continues to poll as normal and accumulated samples are pushed to the cloud when the device is reconnected to the internet.

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