Echelon OpenLDV - Manual (Page 75)

OpenLDV Programmer’s Guide 67
turnaround
If the turnaround bit is set, the message is a turnaround message, that is, a
message sent from one network variable to another network variable on the
same device.
pool
Set the pool bit should 0 for a downlink message.
response
Set the response bit to 1 for a downlink response message, and 0 otherwise. If
it is set for an uplink message, the message is a response to a previously sent
request.
length
The length field in the message header is distinct from the length field in the
application layer header. The length field the message header indicates the
number of bytes for the message data.
Network Address
The network address specifies the address for network (niCOMM) messages,
which includes application messages as well as network variable messages. The
network address is not used for local (niNETMGMT) messages or for implicitly
addressed downlink messages, but it must be present in the application buffer.
The type definition for ExplicitAddr is a union of three structures, depending on
the type of message buffer. For more information about address modes and the
corresponding structures, see the ISO/IEC 14908-1 protocol specification.
The OpenLDV Developer Example also contains an example definition of the
related structures in the OpenLDVdefinitions.h header file.
SendAddrDtl
This structure is used for a downlink, explicitly addressed message, and contains
the destination address of the downlink message in one of four formats,
depending on the address mode. The address modes for sending explicitly
addressed messages are broadcast, group, subnet/node, Neuron ID, local, and
implicit. The SendAddrDtl formats for downlink messages sent using each of
these address modes are displayed below.