B&B Electronics VFG3000 - Manual - Manual (Page 36)

P ROTOCOL C ONVERSION V LINX F IELDBUS G ATEWAY M ANAGER U SER M ANUAL
P AGE 20
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ROTOCOL
C
ONVERSION
In addition to exposing internal data tags via slave protocols, Gateway Blocks can also be
used to expose data that is obtained from other remote devices, or to move data between two
such master devices. This unique protocol conversion feature allows much tighter integration
between elements of your control system, even when using simple, low-cost devices.
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ASTER AND
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LAVE
Exposing data from other devices over a slave protocol is simply an extension of the mapping
process described above, except this time, instead of dragging a tag from the right-hand pane,
you should expand the appropriate master device, and drag across the icon that represents the
registers that you want to expose. You will then be asked for a start address in the master
device, and the number of registers to map, and the mappings will be created as shown.
In this example, registers N7:0 through N7:7 in an Allen-Bradley controller have been
exposed for access via Modbus TCP/IP as registers 40001 through 40008 . Fieldbus Gateway
Manager will automatically ensure that these data items are read from the Allen-Bradley PLC
so as to fulfill Modbus requests, and will automatically convert writes to the Modbus registers
into writes to the PLC. This mechanism allows even simple PLCs to be connected on an
Ethernet network.
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ASTER AND
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ASTER