Siemens SIMATIC TIWAY 1 - Manual (Page 37)

OPERATION AND APPLICATION
UNILINK HOST ADAPTER 2–27
USER MANUAL
The BROADCAST NETWORK DATA TRANSFER command will send the
Primitive to all logically connected secondary devices on the network and is
provided for backward compatibility with the original TIWAY I Host Adapter.
The Broadcast/Poll sequence is more efficiently handled with macros discussed
in Paragraph 2.10. Unlike the SEND NETWORK DATA command, the
responses from the secondaries do not automatically return. If the command is
accepted, the command code will be returned, then your applications software
MUST issue a POLL command to each secondary to collect the Primitive
response.
CAUTION
You should not issue the BROADCAST
NETWORK DATA TRANSFER command if your
network contains Intelligent Tank
Transmitters (ITTs) as secondary devices or
you could loose responses. Also, sending a
BROADCAST NETWORK DATA TRANSFER
command when your adapter is configured as
either an MHIU or an HIU will cause an
network HDLC error to be logged even though
the information was received. This error will
be included in the statistics from the READ
SECONDARY DIAGNOSTICS, REPORT HIU
STATUS, REPORT NETWORK MANAGER
SECONDARY STATISTICS and the REPORT
NETWORK MANAGER NETWORK
STATISTICS commands.
The POLL command can only be used by an adapter configured as an
MHIU/EHA, however, the broadcast/poll sequence can be implemented in other
operating modes with macros. Example 2–1 is a typical sequence for the
broadcast/poll commands.