An Internal Cache Memory is a memory of this Driver that stores both data received from a device and data sent to a device.

Cache Memory of Received Data

The ASDUs of data received from a device are stored on the internal cache memory, grouped by type and address. To read data stored on the cache memory, declare a Tag for Reading Events from Cache Memory, informing the type of ASDU and the object's address.

Cache Memory of Sent Data

To handle data to send, this Driver in Slave mode keeps the following memory areas:

•Cache: Keeps the current value of an object

•Queue of events with high priority: Contains a list of events to send to a Master with high priority

•Queue of events with low priority: Contains a list of events to send to a Master with low priority

•Queue of events with responses from Commands: Contains a list of results of Commands to send to a Master

When a connection to a Master is lost, a Slave clears the event queues and keeps only the cache memory with the current value of each object.

This Driver in Slave mode can be configured to keep in memory the event queues with high and low priority even in case of disconnection. To enable and configure the size of these queues, configure the Offline Buffers option of the Slave group on the Properties tab of this Driver's configuration window according to the next values:

•Offline Class 1 buffering and Offline Class 1 Buffer size (events): Enables keeping n events with high priority (Class 1) while the Slave is disconnected from a Master

•Offline Class 2 buffering and Offline Class 2 Buffer size (events): Enables keeping n events with low priority (Class 2) while the Slave is disconnected from a Master