Campbell Scientific RF450 Spread Spectrum Radio - Manual (Page 9)

RF450 Spread Spectrum Radio
Master
Slave
Slave
Slave
FIGURE 3.1-1. Simplest Form of a Multi-Point Network
In a multi-point network, outbound packets from the Master or repeater to
Slaves or other repeaters are sent a set number of times determined by the user.
The receiving transceiver, Slave or repeater, will accept the first packet
received with the correct signature (32 bit CRC). However, the packet is not
acknowledged. On the return trip to the Master, all packets sent are
acknowledged or retransmitted until they are acknowledged. Therefore, the
return link in a multi-point network is generally very robust.
Traditionally, a multi-point network is used in applications where data is
collected from one to many dataloggers and reported back to one central site.
The central site is typically a PC running LoggerNet, but could be a datalogger.
Refer to Appendix A for different installation scenarios.
Though the radios may be setup in a point-to-point mode, this manual will only
address multi-point applications, as this is the only way to take advantage of
the low-power mode of the Slave radios at the datalogger site. This reduces the
required power at remote sites from about 75mA to less than 10mA in most
applications.
3.2 PakBus Graph
PakBus Graph is a LoggerNet utility that graphically depicts the devices and
connections in a PakBus datalogger network. In PakBus graph, the LoggerNet
server is typically represented by PakBus address 4094, and each of the
PakBus dataloggers that have been configured in Setup will be shown by the
PakBus address in brackets followed by its name assigned through LoggerNet
setup.
Because RF450 networking protocols are used to direct packets, not PakBus
protocols, the network's representation in PakBus Graph may be significantly
different than one would expect. Figure 3.2-1 depicts the physical network of
six dataloggers and one LoggerNet server. Dataloggers numbered 1 and 2
route packets to other dataloggers from the LoggerNet server.
3