Data Logging
In Settings → Data Logging, create a channel and bind the variables to record. Several variables can share one channel, and values recorded in the same pass are stored with the same timestamp. With Auto logging enabled (the default), variable values are saved to the controller's database at each logging interval (one minute by default). Recorded data is viewed with the Historical Chart and Historical Table widgets.
Independently of interval recording, the Data Logging action records a single entry at a specific moment. To record only at event times, turn off Auto logging and use the action alone.
The retention policy determines how much history is kept. The default is None (unlimited); choosing size (100MB by default), count (100,000 records), or duration (30 days) deletes the oldest records once the limit is exceeded. For channels that run long-term, set a retention policy when creating the channel.
| Field | Description |
|---|---|
| Channel Name | The name that identifies the logging channel. Records are kept separately per channel name in the controller's SQLite database. |
| Logging Variables | The variables to record. Several variables can be selected, and values recorded in one pass are stored with the same timestamp. |
| Max Size (MB) | Applies when the limit type is Size. Once the records exceed this size, the oldest records are deleted first. The minimum is 1MB. |
| Max Records | Applies when the limit type is Count. Once the records exceed this number, the oldest records are deleted first. The minimum is 100. |
| Retention Days | Applies when the limit type is Duration. Records older than this period are deleted automatically. The minimum is 1 day. |