The data link layer manages the logical
link between sender and receiver. Its primary tasks are station
addressing and error detection.
The DNP3 driver uses the FT3 format. This
means that every octet is enlarged by a start bit and a stop bit
(a 16 bit CRC is used), by what a asynchronous data communication
is possible.
In addition, the data link layer uses only
the balanced (symmetrical) communication.
Requests and responses in a multidrop topology
may cause a certain time delay.
Using the multidrop topology the "Collision
Avoidance" is realized through different access times on
the bus. |