Varec RS-232, Installation And Operation Manual

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Introduction
2 Installation and Operations Manual
1.2 Function and System Design
The 8410 WFT provides wireless 900 MHz RS-232 and RS-485 data communications.
Figure 1-1: Example of Point-to-Point and Multipoint Systems
Varec’s wireless products are able to function over point-to-point or multipoint systems.
Traditionally, a multipoint network is used in applications where data is collected from many
instruments and reported back to one central site.
Note It is important to note the differences between point-to-point and point-to-multi-
point systems. In a point-to-point system all data communications are acknowledged,
whether sent from the master to the slave or from the slave to the master. In a point-to-
multipoint system outbound communications from the master are sent a user-defined
number of times. The receiving unit, slave or repeater, will accept the first packet received
that meets security requirements. A point-to-point system is limited to one master and one
slave transceiver. Repeaters may be added to extend the reach of the network, but no other
master or slave may be added. In a point-to-multipoint system, the transceiver—desig-
nated as a master— is able to communicate with numerous slaves. In its simplest form, a
tank gauge multipoint network functions with the master (8420 WBT) broadcasting its mes-
sages to all slaves (8410 WFT) and the slaves responding to the master when given data by
the connected tank gauge transmitter.
FuelsManager
Software
8130 RTU
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Star Communcations e.g. Mark/Space
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