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.
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:
Log in to the Green Stack Console and navigate to Building Engineering
Select a site from the system tree
Select Trend Collectors
Add a New Trend Collector
To add a new Trend Collector:
Click New Collector
Select the desired Target Point
Select the desired Collection Strategy (see above)
Select the desired Sample Cadence (interval)
Click Add Collector to save the collector
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:
Click Configure Collector
Toggle Data Collection as desired
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:
Select a Manual Upload trend collector from the list
Click the Samples tab
Click Upload Samples to open the Sample Upload Wizard
Select the target CSV data file
Adjust the UTC Offset as needed
Click Upload & Review to pre-process the sample data
Review the sample data and click Commit Samples
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:
Select the checkbox next to one or more Trend Collectors in the list
Click the Trash Can icon
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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