WirelessHART Fieldgate SWG70, Руководство по эксплуатации

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WirelessHART Fieldgate SWG70 3 Function and System Design
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3.3 Connection to host applications
Fieldgate SWG70 also makes wireless communication accessible to HART-capable host systems via
its Ethernet or serial interfaces through the following functions.
3.3.1 Instrument List
WirelessHART devices in the network are made available to host systems via an instrument list. This
list contains one or more I/O cards. Every I/O card has one or more channels. Up to 15 field devices
(for WirelessHART Adapter SWA70 max. four) can be connected in multidrop mode to each
channel, see Fig. 3-3. The list itself can be up and downloaded, see Chapter 10.1.
Fieldgate SWG70 assigns a virtual I/O card to each WirelessHART device. The I/O cards are
assigned to the WirelessHART devices in the order in which they join the network. New
WirelessHART devices in the network are assigned to the next available I/O card, which is added
to the end of the instrument list (First-in-First-Out principle).
Within an I/O card, the WirelessHART device itself as well as status information is assigned to
Channel 0. If the WirelessHART device is an adapter, all field devices connected to it are assigned
to channel 1 (multi-drop mode). The list of the connected field devices is also called sub-device list.
Fig. 3-3: Instrument list
If a WirelessHART device loses communication to the gateway, it stays assigned to the I/O card
initially allocated to it. When communication is established again, the device thus has the same
position in the instrument list that it had before.
The same principle applies to the field devices connected to the WirelessHART adapter. When
communication to the gateway is lost, the long tags of the filed devices are stored. After
communication has been established again, the field devices regain their previous position in the
instrument list.
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WirelessHART Gateway
I/O Card 1
I/O Card 2
Channel 0
WirelessHART Field Device
WirelessHART Adapter
Channel 0
Channel 1
HART Field Device 1
HART Field Device 2
HART Field Device 3
Network Structure I/O Structure Instrument List
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