Can I access the accelerometer data in the BT510 sensor?

The Sentrius™ BT510 advertises events. An event can be a temperature measurement, an alarm ,a battery measurement, a button press, a door opening/closing, or movement. The configuration of a sensor determines what kind of events it generates.

Access to accelerometer values is not possible but it is possible to configure the accelerometer sensitivity. You can configure a sensor using a Bluetooth connection and the Laird virtual serial port (VSP) service. The protocol sent over the virtual serial port is JSON-RPC version 2. This allows you to add new commands and features without changing the Bluetooth interface. The BT510 accelerometer creates a movement event.
More details can be found in the BT510 user guide.