Data Logs: Description and Reference Information

Use data logging in Tracer Ensemble to collect historical data from your building control systems. This data can be used for a variety of purposes, from monthly energy usage reporting to equipment troubleshooting. After the data is collected, you can view one or more logs as a graph or a table in Tracer Ensemble or you can export the data for use by other applications for storing or presenting the data.

Types of Data Logs

There are two types of data log: (standard) Tracer Ensemble data logs and Panel data logs:

Tracer Ensemble data logs—This type of data log is initiated by and essentially controlled by Tracer Ensemble. You select a data point of interest and specify details about when the data is sampled, and Tracer Ensemble requests and records the data according to your specification. The data is sampled and collected at the same time.
Panel data logs—A panel data log is a panel trend log being read by Tracer Ensemble. Because the trend log already has a sampling frequency, you only need to specify when the data is collected. And because the data is collected and stored in the panel when it is sampled, Tracer Ensemble does not need to collect each sample one at a time.

Time Zones

With standard Tracer Ensemble data logs, the Tracer Ensemble server applies the time and date information to each data point. Assuming the user's time zone is set correctly, the time and date stamp on each data point will be adjusted to the user's local time. With Panel data logs, the panel applies the time and date information to each data point. All data points shown in Tracer Ensemble will have the panel's local time on them, not the user own time zone.

Snapshot Trends

Some panel trend objects are configured to log data only after an event occurs. These are called snapshot trends. Tracer Ensemble has no way of knowing when that event has occurred. Similarly, trends may be configured to collect data only for part of a day. Tracer Ensemble follows the same algorithm for collection times for these trend types as with the standard trend objects, despite the fact that there may not be any new data in the trend.

Failed Panel Communication

If Tracer Ensemble is unable to retrieve data log information from the building control panel, the data request will be retried two times. When three attempts have failed, Tracer Ensemble stops attempting to perform the scheduled data collection and a failure message is added to the system log with the following information:

Date and time the failure occurred
Name of the building that Tracer Ensemble was requesting data from
Name of the data log that Tracer Ensemble was collecting data for
Any available communications error details

Tracer Ensemble will attempt to collect data from the building controller at the next scheduled data collection time. For panel data logs, it will occur 15 minutes after the failed attempt.

Tracer Ensemble Server Failure

If Tracer Ensemble is not operational at the time it is scheduled to collect data from a panel data log, it will collect the data it missed when it is operational again.

Data Log Staging

To minimize spikes in network traffic, Tracer Ensemble monitors its scheduled communications tasks to warn you of possible bottlenecks. So, when you add new data logs, they system examines the specific collection times compared to the number of data points and buildings involved and evaluates the system performance impact. If the requested collection times would degrade network or system performance, Tracer Ensemble will inform you of these concerns and suggest alternative collection times to alleviate the stress. If you see the warning, your choices will be:

Proceed as specified and accept network risks. The system attempts to honor the data log request, but may limit data collections if the system begins to overload.
Change the parameters of the data log.
Allow the system to stage the requests. The data requests are sent out in smaller batches and the system monitors its performance before releasing each batch. This reduces the spike of network traffic. In this case the data log may show data and time stamps that start several minutes later than expected.

Collection Notification

Some building control panels have an option to communicate with the workstation to request that the workstation collect the data in its data log. Tracer Ensemble supports this notification for all building control panel types. If the user-specified or algorithmic intervals selected for the data log are scheduled to collect the data before a collection notification is received, Tracer Ensemble collects the data log information at that time rather than waiting for the collection notification. When you create a panel data log, Tracer Ensemble subscribes to this service automatically when applicable.