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The BT710 is designed to log data from other compatible tracer devices it observes during its BLE scan operations. The
logging functionality can be disabled through the Log Interval parameter (set Log Interval to 0).
The following diagram (
Figure 5 ) shows the data logging timeline and how various parameters affect each logging phase.
Figure 5 - Data logging timeline
As a tracer detects remote tracer
s (“remotes”) in each BLE scan, the discovery database is updated and the remote steps
through three phases of logging throughout a single Contact Period.
▪
Discovery Phase
– Remote tracers are tracked in a RAM-only discovery database for each scan they are detected.
Once the total detection time is greater than the configured Discovery Duration, the records for the remote are committed
to a Flash-based log and the remote enters Tracking Phase. If a remote is only detected fewer scan intervals than the
configured Discovery Duration within a given Contact Period, the remote is not logged to Flash. This is useful for
situations where tracers are in proximity for very brief periods of time and do not warrant storage to the Flash-based log.
Discovery Phase stores a maximum of 10 records per remote before automatically moving into Tracking Phase.
▪
Tracking Phase
– Remote tracers in the Tracking Phase get an additional record in the Flash-based log for every scan
interval they are detected, up to the maximum records that can be recorded for the duration of the Tracking Phase (set
with the Tracking Duration parameter).
▪
Untracked Phase
– If a remote tracer has been detected for the entirety of the Tracking Phase, no more records are
made for that remote until the Contact Period expires or that entry is collected by a gateway. This limits the maximum
number of Flash log records that are used by a single remote per Contact Period, allowing remaining Flash space to be
used for detection and logging of other remote devices during the Contact Period.
The number of unique remote tracers that can be logged is a function of the Scan Interval and Tracking Duration parameters.
For example, with Scan Interval of 30 seconds, Tracking Duration of 15 minutes and Contact Period of 24 hours, up to 50
remote tracers can be logged for 1 week before the log is full. Once the log is full, the oldest entries are overwritten with new
entries in first-in first-out order. The following data is logged at each scan interval from a remote tracer
’s advertisement:
Figure 6 - Data logged for each remote tracer detected in BLE scans
0 TIME
(SECONDS)
30 60 90 120 330 270 300
REMOTE TRACKER
DETECTED IN SCAN
Scan Interval
30 Seconds
Discovery Duration
300 Seconds
Tracking Phase
Starts
(Flash-based Logging)
1770 1800
Tracking Duration
1800 Seconds
1830 1860
Logging Timeline for Each Remote
Tracker Starts on First Detection
(RAM-only Logging)
1890 1920 1950
Untracked Phase Starts
(No Logs Recorded for This Remote
Tracker Until Next Contact Period)
86,370 86,400
Contact Period
86,400 Seconds (1 Day)
Logging Timeline Resets
After Contact Period Expires
Scan Duration
2 Seconds
DISCOVERY PHASE TRACKING PHASE UNTRACKED PHASE
Device ID Timestamp Status RSSI Motion Status TX Power