Echelon OpenLDV - Manual (Page 11)

OpenLDV Programmer’s Guide 3
Client Applications
OpenLDV applications, such as the LNS Server and the LonScanner Protocol
Analyzer, use the OpenLDV application programming interface (API) to
communicate with L ON W ORKS network interfaces.
Echelon’s LNS software provides a high-level interface to L ON W ORKS networks
that simplifies managing network interfaces. The LNS software is a powerful,
flexible network management platform you can use with high-performance
Layer-2 or Layer-5 network interfaces, as well as with IP-852 routers (such as
the i.LON 600 or SmartServer). The LNS Server provides a wide variety of
network management and monitor and control services, and allows multiple
client access to the same network interface.
For most customers, choosing the LNS software platform will result in a high-
quality application that can be developed more quickly, requiring less knowledge
of low-level details, than with other network management platforms, including
the OpenLDV platform. However, the OpenLDV API provides a low-level
interface for writing Windows based L ON W ORKS software for use with
L ON W ORKS network interfaces.
You can use the OpenLDV API to write your own application that sends and
receives messages through L ON W ORKS network interfaces, using either a
LonTalk Layer 2 or Layer 5 interface. These messages can initialize and
terminate communications with the network interface, retrieve incoming
messages, or transmit outgoing messages. See Chapter 2, Using the OpenLDV
API, on page 9, and Chapter 3, Sending and Receiving Messages with the
OpenLDV API, on page 57, for information about these topics.
OpenLDV Driver
You can use the OpenLDV runtime with network management or monitoring and
control applications. For example, for a self-installed system with fixed network
addresses, you can use the OpenLDV API to create an application that sends
messages to test the devices on your network. This diagnostic application could
periodically send request messages to devices in the system to check their status.
You can also use the OpenLDV API to create a data logging application to
monitor and retrieve network variable values from the various devices on your
network.
The OpenLDV 4.0 driver and API are backward-compatible with previous
versions of the driver and the API (but see Hardware and Software Requirements
on page 5 for the OpenLDV 4.0 requirements, which differ from those of prior
releases).
To develop an OpenLDV application, you must understand LonTalk message
formats and network interface state management. You also need to be able to
manage low-level LonTalk messaging details, such as LonTalk reference IDs.
Chapters 3 and 4 of this document describe some of the LonTalk message formats
that you can use with the OpenLDV API. In addition, the section Message
Header on page 62 includes some discussion of LonTalk reference IDs. See the
ISO/IEC 14908 Control Network Protocol specification for detailed information
about the LonTalk protocol.