Echelon OpenLDV - Manual (Page 20)

12 Using the OpenLDV API
Application Layer
OpenLDV API
Presentation Layer
OpenLDV Application
OpenLDV Driver (Ldv32.dll)
SLTA
Link Layer
PCLTA
Link Layer
PCC
Link Layer
USB
Link Layer
SLTA-10
PCLTA-10
PCLTA-20
PCC-10
U10
U20
L
ON
W
ORKS
Network
xDriver
Link Layer
SmartServer
i.LON
Interfaces
Compatible
with
OpenLDV
API
OpenLDV
Interface
and Driver
Software
OpenLDV
Application
Figure 4. OpenLDV Application Architecture
An OpenLDV application implements the application and presentation layers,
and uses the OpenLDV API (with the OpenLDV driver, Ldv32.dll) as an
interface layer to communicate with a network interface. The network interfaces
communicate with the L
ON
W
ORKS
network. Although the figure shows Echelon
network interfaces, most third-party network interfaces can also use the
OpenLDV driver.
An OpenLDV application that uses the OpenLDV API can establish downlink
connections (session initiation from the application to the local or remote network
interface), and it can accept uplink session requests (session initiation from the
remote network interface, using the xDriver Broker service, to the application).
Application Layer
The application layer is responsible for sending data to the L ON W ORKS network
through output network variables and outgoing application messages, and
receiving L ON W ORKS network data through input network variables and
incoming application messages. Typically, the bulk of an OpenLDV application’s
code is at the application layer.